EM64T_Intel111_flags.xml
SPEC CPU2006 Flag Description for the Intel(R) C++ Compiler 11.1
for IA32 and Intel 64 applications and Intel(R) Fortran Compiler 11.1 for IA32 and Intel 64
applications
Copyright © 2006 Intel Corporation. All Rights Reserved.
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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.
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 an 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
Sets the stack size to n kbytes, or unlimited to allow the stack size
to grow without limit.
submit= MYMASK=`printf '0x%x' \$((1<<\$SPECCOPYNUM))`; /usr/bin/taskset \$MYMASK $command
When running multiple copies of benchmarks, the SPEC config file feature
submit is sometimes used to cause individual jobs to be bound to
specific processors. This specific submit command is used for Linux.
The description of the elements of the command are:
- /usr/bin/taskset [options] [mask] [pid | command [arg] ... ]:
taskset is used to set or retreive the CPU affinity of a running
process given its PID or to launch a new COMMAND with a given CPU
affinity. The CPU affinity is represented as a bitmask, with the
lowest order bit corresponding to the first logical CPU and highest
order bit corresponding to the last logical CPU. When the taskset
returns, it is guaranteed that the given program has been scheduled
to a legal CPU.
The default behaviour of taskset is to run a new command with a
given affinity mask:
taskset [mask] [command] [arguments]
- $MYMASK: The bitmask (in hexadecimal) corresponding to a specific
SPECCOPYNUM. For example, $MYMASK value for the first copy of a
rate run will be 0x00000001, for the second copy of the rate will
be 0x00000002 etc. Thus, the first copy of the rate run will have a
CPU affinity of CPU0, the second copy will have the affinity CPU1
etc.
- $command: Program to be started, in this case, the benchmark instance
to be started.
Intel(R) MPI Library 3.2 for Linux* options and environment variables
Job startup command flags
-perhost <# of processes>
Use this option to place the indicated number of consecutive
MPI processes on every host in group round robin fashion. The number
of processes to start is controlled by the option -n as usual.
-n <# of processes> or -np <# of processes>
Use this option to set the number of MPI processes to run the current arg-set.
-genv <ENVVAR> <value>
Use this option to set the <ENVVAR> environment variable
to the specified <value> for all MPI processes.
Environment variables
I_MPI_DEVICE=<device>[:<provider>]
Select the particular network fabric to be used.
sock - Sockets
shm - Shared-memory only (no sockets)
ssm - Combined sockets + shared memory
(for clusters with SMP nodes)
rdma - RDMA-capable network fabrics including InfiniBand*,
Myrinet* (via DAPL*)
rdssm - Combined sockets + shared memory + DAPL*
(for clusters with SMP nodes and RDMA-capable network fabrics)
I_MPI_FALLBACK_DEVICE=(enable|disable)
Set this environment variable to enable fallback to the available
fabric. It is valid only for rdssm and rdma modes.
Fall back to the shared memory and/or socket fabrics
if initialization of the DAPL* fabric fails.
This is the default value.
Terminate the job if the fabric selected by the I_MPI_DEVICE
environment variable cannot be initialized.
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Invoke the Intel C compiler for MPI applications.
You need binutils 2.16.91.0.7 or later with this compiler to support new instructions on Intel Core 2 processors
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Invoke the Intel C++ compiler for MPI applications.
You need binutils 2.16.91.0.7 or later with this compiler to support new instructions on Intel Core 2 processors
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Invoke the Intel Fortran compiler for MPI applications.
You need binutils 2.16.91.0.7 or later with this compiler to support new instructions on Intel Core 2 processors
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Invoke the Intel C/C++ compiler for Intel 64 applications
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Invoke the Intel C/C++ compiler for 32-bit applications
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Invoke the Intel C compiler for IA32 applications.
You need binutils 2.16.91.0.7 or later with this compiler to support new instructions on Intel Core 2 processors
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Invoke the Intel C++ compiler for IA32 and Intel 64 applications.
You need binutils 2.16.91.0.7 or later with this compiler to support new instructions on Intel Core 2 processors
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Invoke the Intel Fortran compiler for IA32 and Intel 64 applications.
You need binutils 2.16.91.0.7 or later with this compiler to support new instructions on Intel Core 2 processors
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Compiler option to set the path for include files.
Used in some integer peak benchmarks which were built using the Intel 64-bit C++ compiler.
Compiler option to set the path for library files.
Used in some integer peak benchmarks which were built using the Intel 64-bit C++ compiler.
Compiler option to set the path for include files.
Used in some peak benchmarks which were built using the Intel 32-bit C++ compiler.
Compiler option to set the path for library files.
Used in some integer peak benchmarks which were built using the Intel 32-bit C++ compiler.
Compiler option to set the path for include files.
Used in some peak benchmarks which were built using the Intel 32-bit Fortran compiler.
Compiler option to set the path for library files.
Used in some integer peak benchmarks which were built using the Intel 32-bit Fortran compiler.
Define the MPICH_IGNORE_CXX_SEEK macro at compilation stage to catastrophic error:
"SEEK_SET is #defined but must not be for the C++ binding of MPI" when compiling C++ MPI application.
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For mixed-language benchmarks, tell the compiler to convert routine names to
lowercase for compatibility
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For mixed-language benchmarks, tell the compiler to assume that routine
names end with an underscore
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Tell the compiler to treat source files as C++ regardless of the file extension
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.
On IA-32 Windows platforms, -O1 sets the following:
/Qunroll0, /Oi-, /Op-, /Oy, /Gy, /Os, /GF (/Qvc7 and above),
/Gf (/Qvc6 and below), /Ob2, and /Og
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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
On IA-32 Windows platforms, -O2 sets the following:
/Og, /Oi-, /Os, /Oy, /Ob2, /GF (/Qvc7 and above), /Gf (/Qvc6
and below), /Gs, and /Gy.
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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. On IA-32
Windows platforms, -O3 sets the following:
/GF (/Qvc7 and above), /Gf (/Qvc6 and below), and /Ob2
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Tells the compiler the maximum number of times to unroll loops.
This option enables additional interprocedural optimizations for single
file compilation. These optimizations are a subset of full intra-file
interprocedural optimizations. One of these optimizations enables the
compiler to perform inline function expansion for calls to functions
defined within the current source file.
Multi-file ip optimizations that includes:
- inline function expansion
- interprocedural constant propogation
- dead code elimination
- propagation of function characteristics
- passing arguments in registers
- loop-invariant code motion
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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.
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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.
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-scalar-rep enables scalar replacement performed during loop transformation.
To use this option, you must also specify O3. -scalar-rep- disables this optimization.
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This options tells the compiler to assume no aliasing in the program.
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The -fast option enhances execution speed across the entire program
by including the following options that can improve run-time performance:
-O3 (maximum speed and high-level optimizations)
-ipo (enables interprocedural optimizations across files)
-xT (generate code specialized for Intel(R) Core(TM)2 Duo processors, Intel(R) Core(TM)2 Quad processors
and Intel(R) Xeon(R) processors with SSSE3)
-static (disable -prec-div)
Statically link in libraries at link time
-no-prec-div (disable -prec-div)
where -prec-div improves precision of FP divides (some speed impact)
To override one of the options set by /fast, specify that option after the
-fast option on the command line. The exception is the xT or QxT option
which can't be overridden. The options set by /fast may change from
release to release.
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Compiler option to statically link in libraries at link time
Code is optimized for Intel(R) Core(TM)2 Duo processors, Intel(R) Core(TM)2 Quad
processors and Intel(R) Xeon(R) processors with SSSE3.
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.
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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.
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Code is optimized for Intel(R) processors with support for SSE 4.1 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.
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Code is optimized for Intel(R) processors with support for SSSE3 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.
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Code is optimized for Intel Pentium M and compatible Intel processors. 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.
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Code is optimized for Intel Pentium 4 and compatible Intel processors;
this is the default for Intel?EM64T systems. The resulting code may contain
unconditional use of features that are not supported on other processors.
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Tells the auto-parallelizer to generate multithreaded code for loops that can be safely executed in parallel.
To use this option, you must also specify option O2 or O3. The default numbers of threads spawned is equal to
the number of processors detected in the system where the binary is compiled. Can be changed by setting the
environment variable OMP_NUM_THREADS
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The use of -Qparallel to generate auto-parallelized code requires spport libraries that are
dynamically linked by default. Specifying libguide.lib on the link line, statically links in
libguide.lib to allow auto-parallelized binaries to work on systems which do not have the dynamic version
of this library installed.
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The use of -Qparallel to generate auto-parallelized code requires spport libraries that are
dynamically linked by default. Specifying libguide40.lib on the link line, statically links in
libguide40.lib to allow auto-parallelized binaries to work on systems which do not have the
dynamic version of this library installed.
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Optimizes for Intel Pentium 4 and compatible processors with Streaming SIMD Extensions 2 (SSE2).
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(disable/enable[default] -[no-]prec-div)
-prec-div improves precision of floating-point divides. It has a slight
impact on speed. -no-prec-div disables this option and 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 which will enable the
default -prec-div and the result is more accurate, with some
loss of performance.
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Instrument program for profiling for the first phase of
two-phase profile guided otimization. This instrumentation gathers information
about a program's execution paths and data values but does not gather
information from hardware performance counters. The profile instrumentation
also gathers data for optimizations which are unique to profile-feedback
optimization.
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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
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Enable SmartHeap and/or other library usage by forcing the linker to
ignore multiple definitions if present
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Enable SmartHeap library usage by forcing the linker to
ignore multiple definitions
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MicroQuill SmartHeap Library V8.1 available from http://www.microquill.com/
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set the stack reserve amount specified to the linker
Enable/disable(DEFAULT) use of ANSI aliasing rules in
optimizations; user asserts that the program adheres to
these rules.
Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
Directs the compiler to inline calloc() calls as malloc()/memset()
Specify malloc configuration parameters. Specifying a non-zero value will
cause alternate configuration parameters to be set for how malloc allocates and frees
memory
Enables cache/bandwidth optimization for stores under conditionals (within vector loops)
Enable compiler to generate runtime control code for effective automatic parallelization
Select the method that the register allocator uses to partition each routine into regions
routine - one region per routine
block - one region per block
trace - one region per trace
loop - one region per loop
default - compiler selects best option
Select the method that the register allocator uses to partition each routine into regions
routine - one region per routine
block - one region per block
trace - one region per trace
loop - one region per loop
default - compiler selects best option
Enables more aggressive multi-versioning
Make all local variables AUTOMATIC. Same as -automatic
Enables more aggressive unrolling heuristics
Specifies whether streaming stores are generated:
always - enables generation of streaming stores under the assumption that the application is memory bound
auto - compiler decides when streaming stores are used (DEFAULT)
never - disables generation of streaming stores
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Disables inline expansion of all intrinsic functions.
Disables conformance to the ANSI C and IEEE 754 standards for
floating-point arithmetic.
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Allows use of EBP as a general-purpose register in optimizations.
This option enables most speed optimizations, but disables some
that increase code size for a small speed benefit.
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This option enables global optimizations.
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.
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This option tells the compiler to separate functions into COMDATs
for the linker.
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This option enables read only string-pooling optimization.
This option enables read/write string-pooling optimization.
This option disables stack-checking for routines with 4096 bytes
of local variables and compiler temporaries.
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This option is used to indicate that the host system's longs are 8-bytes wide.
Select the particular network fabric to be used.
sock - Sockets
shm - Shared-memory only (no sockets)
ssm - Combined sockets + shared memory
(for clusters with SMP nodes)
rdma - RDMA-capable network fabrics including InfiniBand*,
Myrinet* (via DAPL*)
rdssm - Combined sockets + shared memory + DAPL*
(for clusters with SMP nodes and RDMA-capable network fabrics)
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Set this environment variable to enable fallback to the available
fabric. It is valid only for rdssm and rdma modes.
Fall back to the shared memory and/or socket fabrics
if initialization of the DAPL* fabric fails.
This is the default value.
Terminate the job if the fabric selected by the I_MPI_DEVICE
environment variable cannot be initialized.
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Set the I_MPI_PIN_MODE variable to choose the algorithm used
for pinning process.
mpd - Pin processes inside MPD. Default on SGI* Altix* platform.
lib - Pin processes inside MPI library. Default on other platforms.
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Identify a subset of processors to be used for process pinning
and define ranks placement on this subset. <proclist>
specifies a mapping of logical to physical processors as follows:
all - Use all logical processors.
allsocks - Use only one processor core per a physical package (socket).
allcores - Use all processor cores. This is the default value.
<k>,<l>-<m>,<n> - Use logical processors
<k>, <l> through <m>, and <n>.
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Use this option to place the indicated number of consecutive
MPI processes on every host in group round robin fashion. The number
of processes to start is controlled by the option -n as usual.
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Use this option to set the number of MPI processes
to run the current arg-set.
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