CPU2006 Flag Description
Fujitsu PRIMEQUEST 1800E(Intel Xeon X7560)
Copyright © 2006 Intel Corporation. All Rights Reserved.
Base Portability Flags
-
- -DSPEC_CPU_LP64
![[suite]](http://www.spec.org/auto/cpu2006/flags/suite.png)
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -nofor_main
![[user]](http://www.spec.org/auto/cpu2006/flags/user.png)
- LDPORTABILITY
-
This option specifies that the main program is not written in Fortran.
It is a link-time option that prevents the compiler from linking for_main.o
into applications.
For example, if the main program is written in C and calls a Fortran subprogram,
specify -nofor-main when compiling the program with the ifort command.
If you omit this option, the main program must be a Fortran program.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -nofor_main
- LDPORTABILITY
-
This option specifies that the main program is not written in Fortran.
It is a link-time option that prevents the compiler from linking for_main.o
into applications.
For example, if the main program is written in C and calls a Fortran subprogram,
specify -nofor-main when compiling the program with the ifort command.
If you omit this option, the main program must be a Fortran program.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -nofor_main
- LDPORTABILITY
-
This option specifies that the main program is not written in Fortran.
It is a link-time option that prevents the compiler from linking for_main.o
into applications.
For example, if the main program is written in C and calls a Fortran subprogram,
specify -nofor-main when compiling the program with the ifort command.
If you omit this option, the main program must be a Fortran program.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
Peak Portability Flags
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -nofor_main
- LDPORTABILITY
-
This option specifies that the main program is not written in Fortran.
It is a link-time option that prevents the compiler from linking for_main.o
into applications.
For example, if the main program is written in C and calls a Fortran subprogram,
specify -nofor-main when compiling the program with the ifort command.
If you omit this option, the main program must be a Fortran program.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -nofor_main
- LDPORTABILITY
-
This option specifies that the main program is not written in Fortran.
It is a link-time option that prevents the compiler from linking for_main.o
into applications.
For example, if the main program is written in C and calls a Fortran subprogram,
specify -nofor-main when compiling the program with the ifort command.
If you omit this option, the main program must be a Fortran program.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -nofor_main
- LDPORTABILITY
-
This option specifies that the main program is not written in Fortran.
It is a link-time option that prevents the compiler from linking for_main.o
into applications.
For example, if the main program is written in C and calls a Fortran subprogram,
specify -nofor-main when compiling the program with the ifort command.
If you omit this option, the main program must be a Fortran program.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
-
- -DSPEC_CPU_LP64
- PORTABILITY
-
This option is used to indicate that the host system's integers are 32-bits
wide, and longs and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
Base Optimization Flags
-
- -xSSE4.2
- OPTIMIZE
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- OPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- OPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -xSSE4.2
- OPTIMIZE
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- OPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- OPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -xSSE4.2
- OPTIMIZE
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- OPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- OPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -xSSE4.2
- OPTIMIZE
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- OPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- OPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
Peak Optimization Flags
-
- -xSSE4.2
- PASS2_CFLAGS, PASS2_LDFLAGS
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_CFLAGS, PASS2_LDFLAGS
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- PASS2_CFLAGS, PASS2_LDFLAGS
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -prof-use
- PASS2_CFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
-
-
- -xSSE4.2
- PASS2_CFLAGS, PASS2_LDFLAGS
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_CFLAGS, PASS2_LDFLAGS
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- PASS2_CFLAGS, PASS2_LDFLAGS
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -prof-use
- PASS2_CFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
- -opt-malloc-options=3
- OPTIMIZE
-
The compiler adds setup code in the C/C++/Fortran main function to enable optimal malloc algorithms:
- n=0: Default, no changes to the malloc options. No call to mallopt() is made.
- n=1: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x10000000. Call mallopt with the two settings.
- n=2: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x40000000. Call mallopt with these two settings.
- n=3: M_MMAP_MAX=0 and M_TRIM_THRESHOLD=-1. Call mallopt with these two settings. This
will cause use of sbrk() calls instead of mmap() calls to get memory from the system.
The two parameters, M_MMAP_MAX and M_TRIM_THRESHOLD, are described below
Function: int mallopt (int param, int value) When calling mallopt, the param argument
specifies the parameter to be set, and value the new value to be set. Possible choices
for param, as defined in malloc.h, are:
- M_TRIM_THRESHOLD This is the minimum size (in bytes) of the top-most, releasable chunk
that will cause sbrk to be called with a negative argument in order to return memory
to the system.
- M_TOP_PAD This parameter determines the amount of extra memory to obtain from the system
when a call to sbrk is required. It also specifies the number of bytes to retain when
shrinking the heap by calling sbrk with a negative argument. This provides the necessary
hysteresis in heap size such that excessive amounts of system calls can be avoided.
- M_MMAP_THRESHOLD All chunks larger than this value are allocated outside the normal heap,
using the mmap system call. This way it is guaranteed that the memory for these chunks
can be returned to the system on free. Note that requests smaller than this threshold
might still be allocated via mmap.
- M_MMAP_MAX The maximum number of chunks to allocate
with mmap. Setting this to zero disables all use of mmap.
-
- -ansi-alias
- OPTIMIZE
-
Enable use of ANSI aliasing rules in optimizations. This option tells the compiler to assume that the program
adheres to ISO C Standard aliasability rules.
If your program adheres to these rules, then this option allows the compiler to optimize more aggressively.
If it doesn't adhere to these rules, then it can cause the compiler to generate incorrect code.
-
- -auto-ilp32
- COPTIMIZE
-
This option instructs the compiler to analyze and transform the program so that
64-bit pointers are shrunk to 32-bit pointers, and 64-bit longs (on Linux) are
shrunk into 32-bit longs wherever it is legal and safe to do so.
In order for this option to be effective the compiler must be able to optimize using
the -ipo/-Qipo option and must be able to analyze all library/external calls the program makes.
This option requires that the size of the program executable never exceeds 2^32 bytes and all
data values can be represented within 32 bits. If the program can run correctly in a 32-bit system,
these requirements are implicitly satisfied. If the program violates these size restrictions,
unpredictable behavior might occur.
-
- -xSSE4.2
- OPTIMIZE
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- OPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- OPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
- -xSSE4.2
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -prof-use
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
-
- -auto-ilp32
- CXXOPTIMIZE
-
This option instructs the compiler to analyze and transform the program so that
64-bit pointers are shrunk to 32-bit pointers, and 64-bit longs (on Linux) are
shrunk into 32-bit longs wherever it is legal and safe to do so.
In order for this option to be effective the compiler must be able to optimize using
the -ipo/-Qipo option and must be able to analyze all library/external calls the program makes.
This option requires that the size of the program executable never exceeds 2^32 bytes and all
data values can be represented within 32 bits. If the program can run correctly in a 32-bit system,
these requirements are implicitly satisfied. If the program violates these size restrictions,
unpredictable behavior might occur.
-
- -xSSE4.2
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -prof-use
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
-
- -ansi-alias
- CXXOPTIMIZE
-
Enable use of ANSI aliasing rules in optimizations. This option tells the compiler to assume that the program
adheres to ISO C Standard aliasability rules.
If your program adheres to these rules, then this option allows the compiler to optimize more aggressively.
If it doesn't adhere to these rules, then it can cause the compiler to generate incorrect code.
-
-
- -xSSE4.2
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -prof-use
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
- -opt-malloc-options=3
- OPTIMIZE
-
The compiler adds setup code in the C/C++/Fortran main function to enable optimal malloc algorithms:
- n=0: Default, no changes to the malloc options. No call to mallopt() is made.
- n=1: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x10000000. Call mallopt with the two settings.
- n=2: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x40000000. Call mallopt with these two settings.
- n=3: M_MMAP_MAX=0 and M_TRIM_THRESHOLD=-1. Call mallopt with these two settings. This
will cause use of sbrk() calls instead of mmap() calls to get memory from the system.
The two parameters, M_MMAP_MAX and M_TRIM_THRESHOLD, are described below
Function: int mallopt (int param, int value) When calling mallopt, the param argument
specifies the parameter to be set, and value the new value to be set. Possible choices
for param, as defined in malloc.h, are:
- M_TRIM_THRESHOLD This is the minimum size (in bytes) of the top-most, releasable chunk
that will cause sbrk to be called with a negative argument in order to return memory
to the system.
- M_TOP_PAD This parameter determines the amount of extra memory to obtain from the system
when a call to sbrk is required. It also specifies the number of bytes to retain when
shrinking the heap by calling sbrk with a negative argument. This provides the necessary
hysteresis in heap size such that excessive amounts of system calls can be avoided.
- M_MMAP_THRESHOLD All chunks larger than this value are allocated outside the normal heap,
using the mmap system call. This way it is guaranteed that the memory for these chunks
can be returned to the system on free. Note that requests smaller than this threshold
might still be allocated via mmap.
- M_MMAP_MAX The maximum number of chunks to allocate
with mmap. Setting this to zero disables all use of mmap.
-
- -xSSE4.2
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -prof-use
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
-
- -ansi-alias
- CXXOPTIMIZE
-
Enable use of ANSI aliasing rules in optimizations. This option tells the compiler to assume that the program
adheres to ISO C Standard aliasability rules.
If your program adheres to these rules, then this option allows the compiler to optimize more aggressively.
If it doesn't adhere to these rules, then it can cause the compiler to generate incorrect code.
-
- -xSSE4.2
- OPTIMIZE
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- OPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- OPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
- -xSSE4.2
- PASS2_FFLAGS, PASS2_LDFLAGS
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_FFLAGS, PASS2_LDFLAGS
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- PASS2_FFLAGS, PASS2_LDFLAGS
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -prof-use
- PASS2_FFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
-
- -Ob0
- OPTIMIZE
-
Specifies the level of inline function expansion.
Ob0 - Disables inlining of user-defined functions. Note that
statement functions are always inlined.
Ob1 - Enables inlining when an inline keyword or an inline
attribute is specified. Also enables inlining according
to the C++ language.
Ob2 - Enables inlining of any function at the compiler's
discretion.
-
- -ansi-alias
- OPTIMIZE
-
Enable use of ANSI aliasing rules in optimizations. This option tells the compiler to assume that the program
adheres to ISO C Standard aliasability rules.
If your program adheres to these rules, then this option allows the compiler to optimize more aggressively.
If it doesn't adhere to these rules, then it can cause the compiler to generate incorrect code.
-
-
- -xSSE4.2
- OPTIMIZE
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- OPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- OPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -xSSE4.2
- PASS2_FFLAGS, PASS2_LDFLAGS
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_FFLAGS, PASS2_LDFLAGS
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- PASS2_FFLAGS, PASS2_LDFLAGS
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -prof-use
- PASS2_FFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
-
- -Ob0
- OPTIMIZE
-
Specifies the level of inline function expansion.
Ob0 - Disables inlining of user-defined functions. Note that
statement functions are always inlined.
Ob1 - Enables inlining when an inline keyword or an inline
attribute is specified. Also enables inlining according
to the C++ language.
Ob2 - Enables inlining of any function at the compiler's
discretion.
-
- -xSSE4.2
- PASS2_FFLAGS, PASS2_LDFLAGS
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_FFLAGS, PASS2_LDFLAGS
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- PASS2_FFLAGS, PASS2_LDFLAGS
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -prof-use
- PASS2_FFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
-
-
-
- -opt-malloc-options=3
- OPTIMIZE
-
The compiler adds setup code in the C/C++/Fortran main function to enable optimal malloc algorithms:
- n=0: Default, no changes to the malloc options. No call to mallopt() is made.
- n=1: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x10000000. Call mallopt with the two settings.
- n=2: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x40000000. Call mallopt with these two settings.
- n=3: M_MMAP_MAX=0 and M_TRIM_THRESHOLD=-1. Call mallopt with these two settings. This
will cause use of sbrk() calls instead of mmap() calls to get memory from the system.
The two parameters, M_MMAP_MAX and M_TRIM_THRESHOLD, are described below
Function: int mallopt (int param, int value) When calling mallopt, the param argument
specifies the parameter to be set, and value the new value to be set. Possible choices
for param, as defined in malloc.h, are:
- M_TRIM_THRESHOLD This is the minimum size (in bytes) of the top-most, releasable chunk
that will cause sbrk to be called with a negative argument in order to return memory
to the system.
- M_TOP_PAD This parameter determines the amount of extra memory to obtain from the system
when a call to sbrk is required. It also specifies the number of bytes to retain when
shrinking the heap by calling sbrk with a negative argument. This provides the necessary
hysteresis in heap size such that excessive amounts of system calls can be avoided.
- M_MMAP_THRESHOLD All chunks larger than this value are allocated outside the normal heap,
using the mmap system call. This way it is guaranteed that the memory for these chunks
can be returned to the system on free. Note that requests smaller than this threshold
might still be allocated via mmap.
- M_MMAP_MAX The maximum number of chunks to allocate
with mmap. Setting this to zero disables all use of mmap.
-
- -xSSE4.2
- PASS2_CFLAGS, PASS2_FFLAGS, PASS2_LDFLAGS
-
Code is optimized for Intel(R) processors with support for SSE 4.2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_CFLAGS, PASS2_FFLAGS, PASS2_LDFLAGS
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- PASS2_CFLAGS, PASS2_FFLAGS, PASS2_LDFLAGS
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
- -prof-use
- PASS2_CFLAGS, PASS2_FFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
-
- -auto-ilp32
- COPTIMIZE
-
This option instructs the compiler to analyze and transform the program so that
64-bit pointers are shrunk to 32-bit pointers, and 64-bit longs (on Linux) are
shrunk into 32-bit longs wherever it is legal and safe to do so.
In order for this option to be effective the compiler must be able to optimize using
the -ipo/-Qipo option and must be able to analyze all library/external calls the program makes.
This option requires that the size of the program executable never exceeds 2^32 bytes and all
data values can be represented within 32 bits. If the program can run correctly in a 32-bit system,
these requirements are implicitly satisfied. If the program violates these size restrictions,
unpredictable behavior might occur.
Implicitly Included Flags
This section contains descriptions of flags that were included implicitly
by other flags, but which do not have a permanent home at SPEC.
-
- -O2
-
Enables optimizations for speed. This is the generally recommended
optimization level. This option also enables:
- Inlining of intrinsics
- Intra-file interprocedural optimizations, which include:
- inlining
- constant propagation
- forward substitution
- routine attribute propagation
- variable address-taken analysis
- dead static function elimination
- removal of unreferenced variables
- The following capabilities for performance gain:
- constant propagation
- copy propagation
- dead-code elimination
- global register allocation
- global instruction scheduling and control speculation
- loop unrolling
- optimized code selection
- partial redundancy elimination
- strength reduction/induction variable simplification
- variable renaming
- exception handling optimizations
- tail recursions
- peephole optimizations
- structure assignment lowering and optimizations
- dead store elimination
- Includes:
-
- -O1
-
Enables optimizations for speed and disables some optimizations that increase code size and affect speed.
To limit code size, this option:
- Enables global optimization; this includes data-flow analysis,
code motion, strength reduction and test replacement, split-lifetime
analysis, and instruction scheduling.
- Disables intrinsic recognition and intrinsics inlining.
The O1 option may improve performance for applications with very large
code size, many branches, and execution time not dominated by code within loops.
-O1 sets the following options:
-funroll-loops0, -fno-builtin, -mno-ieee-fp, -fomit-framepointer, -ffunction-sections, -ftz
- Includes:
-
-
-
-
-
-
Platform settings
One or more of the following settings may have been set. If so, the "General Notes" section of the
report will say so; and you can read below to find out more about what these settings mean.
KMP_STACKSIZE
Specify stack size to be allocated for each thread.
KMP_AFFINITY
KMP_AFFINITY = < physical | logical >, starting-core-id
specifies the static mapping of user threads to physical cores. For example,
if you have a system configured with 8 cores, OMP_NUM_THREADS=8 and
KMP_AFFINITY=physical,0 then thread 0 will mapped to core 0, thread 1 will be mapped to core 1, and
so on in a round-robin fashion.
KMP_AFFINITY = granularity=fine,scatter
The value for the environment variable KMP_AFFINITY affects how the threads from an auto-parallelized program are scheduled across processors.
Specifying granularity=fine selects the finest granularity level, causes each OpenMP thread to be bound to a single thread context.
This ensures that there is only one thread per core on cores supporting HyperThreading Technology
Specifying scatter distributes the threads as evenly as possible across the entire system.
Hence a combination of these two options, will spread the threads evenly across sockets, with one thread per physical core.
OMP_NUM_THREADS
Sets the maximum number of threads to use for OpenMP* parallel regions if no
other value is specified in the application. This environment variable
applies to both -openmp and -parallel (Linux and Mac OS X) or /Qopenmp and /Qparallel (Windows).
Example syntax on a Linux system with 8 cores:
export OMP_NUM_THREADS=8
Hardware Prefetch:
This BIOS option allows the enabling/disabling of a processor mechanism to
prefetch data into the cache according to a pattern-recognition algorithm.
In some cases, setting this option to Disabled may improve
performance. Users should only disable this option
after performing application benchmarking to verify improved
performance in their environment.
Adjacent Sector Prefetch:
This BIOS option allows the enabling/disabling of a processor mechanism to
fetch the adjacent cache line within a 128-byte sector that contains
the data needed due to a cache line miss.
In some cases, setting this option to Disabled may improve
performance. Users should only disable this option
after performing application benchmarking to verify improved
performance in their environment.
ulimit -s <n>
Sets the stack size to n kbytes, or unlimited to allow the stack size
to grow without limit.
mkdir /dev/cpuset; mount -t cpuset none /dev/cpuset; echo 1 > /dev/cpuset/memory_spread_page
There are two boolean flag files per cpuset that control where the
kernel allocates pages for the file system buffers and related in
kernel data structures. They are called 'memory_spread_page' and
'memory_spread_slab'.
If the per-cpuset boolean flag file 'memory_spread_page' is set, then
the kernel will spread the file system buffers (page cache) evenly
over all the nodes that the faulting task is allowed to use, instead
of preferring to put those pages on the node where the task is running.
If the per-cpuset boolean flag file 'memory_spread_slab' is set,
then the kernel will spread some file system related slab caches,
such as for inodes and dentries evenly over all the nodes that the
faulting task is allowed to use, instead of preferring to put those
pages on the node where the task is running.
The setting of these flags does not affect anonymous data segment or
stack segment pages of a task.
By default, both kinds of memory spreading are off, and memory
pages are allocated on the node local to where the task is running,
except perhaps as modified by the tasks NUMA mempolicy or cpuset
configuration, so long as sufficient free memory pages are available.
When new cpusets are created, they inherit the memory spread settings
of their parent.
Setting memory spreading causes allocations for the affected page
or slab caches to ignore the tasks NUMA mempolicy and be spread
instead. Tasks using mbind() or set_mempolicy() calls to set NUMA
mempolicies will not notice any change in these calls as a result of
their containing tasks memory spread settings. If memory spreading
is turned off, then the currently specified NUMA mempolicy once again
applies to memory page allocations.
Both 'memory_spread_page' and 'memory_spread_slab' are boolean flag
files. By default they contain "0", meaning that the feature is off
for that cpuset. If a "1" is written to that file, then that turns
the named feature on.
Using numactl to bind processes and memory to cores
For multi-copy runs or single copy runs on systems with multiple sockets, it is advantageous to bind a process to a particular core. Otherwise, the OS may arbitrarily move your process from one core to another. This can affect performance. To help, SPEC allows the use of a "submit" command where users can specify a utility to use to bind processes. We have found the utility 'numactl' to be the best choice.
numactl runs processes with a specific NUMA scheduling or memory placement policy. The policy is set for a command and inherited by all of its children. The numactl flag "--physcpubind" specifies which core(s) to bind the process. "-l" instructs numactl to keep a process memory on the local node while "-m" specifies which node(s) to place a process memory. For full details on using numactl, please refer to your Linux documentation, 'man numactl'
For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact webmaster@spec.org
Copyright 2006-2014 Standard Performance Evaluation Corporation
Tested with SPEC CPU2006 v1.1.
Report generated on Wed Jul 23 09:50:13 2014 by SPEC CPU2006 flags formatter v6906.
![[benchmark]](http://www.spec.org/auto/cpu2006/flags/benchmark.png)