Intel-ic10.1-FP-intel64-linux-flags-file-20071113.xml
SPEC CPU2006 Flag Description for the Intel(R) C++ and Fortran Compiler 10.1
for Intel 64 applications (32-bit versions used at peak for some benchmarks)
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.
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,2.
Thread 0 will mapped to core 2, thread 1 will be mapped to core 3, and
so on in a round-robin fashion.
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 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.
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Invoke the Intel C compiler for Intel 64 applications
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Invoke the Intel C compiler for 32-bit applications
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Invoke the Intel C++ compiler for 32-bit applications
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Invoke the Intel C compiler 10.1 for Intel64 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 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 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 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.
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
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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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
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Tells the compiler the maximum number of times to unroll loops. For example -funroll-loops0 would
disable unrolling of loops.
-fno-builtin disables inline expansion for all intrinsic functions.
This option trades off floating-point precision for speed by removing
the restriction to conform to the IEEE standard.
EBP is used as a general-purpose register in optimizations.
Places each function in its own COMDAT section.
Flushes denormal results to zero.
Is the maximum number of times a loop can be unrolled. To disable loop
enrolling, use -unroll0.
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
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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.
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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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-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
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 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] -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 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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Enable the use of the 64-bit compiler by passing the directory names for the library and include files
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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()
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.
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Enables cache/bandwidth optimization for stores under conditionals (within vector loops)
This option tells the compiler to perform a conditional check in a vectorized loop.
This checking avoids unnecessary stores and may improve performance by conserving bandwidth.
Enable compiler to generate runtime control code for effective automatic parallelization.
This option generates code to perform run-time checks for loops that have symbolic loop bounds.
If the granularity of a loop is greater than the parallelization threshold, the loop will be
executed in parallel. If you do not specify this option, the compiler may not parallelize loops
with symbolic loop bounds if the compile-time granularity estimation of a loop can not ensure
it is beneficial to parallelize the loop.
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
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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
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Multi-versioning is used for generating different versions of the loop based on run time dependence testing,
alignment and checking for short/long trip counts. If this option is turned on, it will trigger more versioning
at the expense of creating more overhead to check for pointer aliasing and scalar replacement.
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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