Base Compiler Invocation
C benchmarks
-
- pgcc
![[user]](http://www.spec.org/auto/cpu2006/flags/user.png)
- CC, LD
-
Invoke the PGI C compiler.
Also used to invoke linker for C programs.
C++ benchmarks
-
- pgcpp
- CXX, LD
-
Invoke the PGI C++ compiler.
Also used to invoke linker for C++ programs.
Invoke the PGI C compiler.
Also used to invoke linker for C programs.
Invoke the PGI C++ compiler.
Also used to invoke linker for C++ programs.
Invoke the PGI C compiler.
Also used to invoke linker for C programs.
Invoke the PathScale C compiler.
Also used to invoke linker for C programs.
Invoke the PathScale C compiler.
Also used to invoke linker for C programs.
Invoke the PathScale C compiler.
Also used to invoke linker for C programs.
Invoke the PathScale C compiler.
Also used to invoke linker for C programs.
Invoke the PGI C++ compiler.
Also used to invoke linker for C++ programs.
Invoke the PathScale C++ compiler.
Also used to invoke linker for C++ programs.
![[benchmark]](http://www.spec.org/auto/cpu2006/flags/benchmark.png)
This macro specifies that the target system uses the LP64 data model; specifically, that integers are 32 bits, while longs and pointers are 64 bits.
This macro indicates that the benchmark is being compiled on an AMD64-compatible system running the Linux operating system.
![[suite]](http://www.spec.org/auto/cpu2006/flags/suite.png)
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.
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.
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.
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.
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.
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.
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.
Portability changes for Linux
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.
This flag can be set for SPEC compilation for Linux using default compiler.
This macro specifies that the target system uses the LP64 data model; specifically, that integers are 32 bits, while longs and pointers are 64 bits.
This macro indicates that the benchmark is being compiled on an AMD64-compatible system running the Linux operating system.
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.
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.
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.
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.
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.
Portability changes for Linux
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.
This flag can be set for SPEC compilation for Linux using default compiler.
Chooses generally optimal flags for the target platform. As of the PGI 7.0 release, the flags "-fast" and "-fastsse" are equivlent for 64-bit compilations. For 32-bit compilations "-fast" does not include "-Mscalarsse", "-Mcache_align", or "-Mvect=sse".
Link with the huge page runtime library and allocate a maximum of 150 huge pages where 150 is a supplied constant value. If no constant value is supplied, then the maximum number of huge pages the application can use is limited by the number of huge pages the operating system has available or the value of the environment variable PGI_HUGE_PAGES.
Note that setting PGI_HUGE_PAGES will override the value of 150. This environment variable is described below in the section "System and Other Tuning Information".
Instructs the compiler to use relaxed precision in the calculation of some intrinsic functions. Can result in improved performance at the expense of numerical accuracy. The default on an AMD system is "-Mfprelaxed=sqrt,rsqrt,order". The default on an Intel system is "-Mfprelaxed=rsqrt,sqrt,div,order"
Interprocedural Analysis option: Specifies the number of concurent IPA second pass compliation proccess that may be performed. This option speeds-up the compilation time on multi-core systems but does not perform any optimizations.
Instructs the compiler to perform interprocedural analysis. Equivalant to -Mipa=align,arg,const,f90ptr,shape,globals,libc,localarg,ptr,pure.
Interprocedural Analysis option: Automatically determine which functions to inline, limit to 2 levels (default). IPA-based function inlining is performed from leaf routines upward.
Specify the type of the target processor as AMD64 Barcelona Processor 64-bit mode.
Staticily link with the PGI runtime libraries. System libraries may still be dynamically linked.
Chooses generally optimal flags for the target platform. As of the PGI 7.0 release, the flags "-fast" and "-fastsse" are equivlent for 64-bit compilations. For 32-bit compilations "-fast" does not include "-Mscalarsse", "-Mcache_align", or "-Mvect=sse".
Link with the huge page runtime library and allocate a maximum of 150 huge pages where 150 is a supplied constant value. If no constant value is supplied, then the maximum number of huge pages the application can use is limited by the number of huge pages the operating system has available or the value of the environment variable PGI_HUGE_PAGES.
Note that setting PGI_HUGE_PAGES will override the value of 150. This environment variable is described below in the section "System and Other Tuning Information".
Instructs the compiler to use relaxed precision in the calculation of some intrinsic functions. Can result in improved performance at the expense of numerical accuracy. The default on an AMD system is "-Mfprelaxed=sqrt,rsqrt,order". The default on an Intel system is "-Mfprelaxed=rsqrt,sqrt,div,order"
Generate zero-overhead C++ exception handlers.
Interprocedural Analysis option: Specifies the number of concurent IPA second pass compliation proccess that may be performed. This option speeds-up the compilation time on multi-core systems but does not perform any optimizations.
Instructs the compiler to perform interprocedural analysis. Equivalant to -Mipa=align,arg,const,f90ptr,shape,globals,libc,localarg,ptr,pure.
Interprocedural Analysis option: Automatically determine which functions to inline, limit to 2 levels (default). IPA-based function inlining is performed from leaf routines upward.
Specify the type of the target processor as AMD64 Barcelona Processor 32-bit mode.
Staticily link with the PGI runtime libraries. System libraries may still be dynamically linked.
-march=<cpu-type>
Compiler will optimize code for selected cpu-type:
opteron, athlon, athlon64, athlon64fx, barcelona, em64t,
pentium4, xeon, core, anyx86, auto.
The default value, auto, means to optimize for the platform
on which the compiler is running,
as determined by reading /proc/cpuinfo.
anyx86 means a generic 32-bit x86 processor
without SSE2 support.
barcelona is AMD's first Quad-core processor family.
-fb_create <path>
Used to specify that an instrumented executable program is to be
generated. Such an executable is suitable for producing feedback
data files with the specified prefix for use in feedback-directed
optimization (FDO).
The commonly used prefix is "fbdata".
This is OFF by default.
During the training run, the instrumented executable produces information regarding execution paths and data values, but does not generate information by using hardware performance counters.
-fb_opt <prefix for feedback data files>
Used to specify feedback-directed optimization (FDO) by extracting
feedback data from files with the specified prefix, which were
previously generated using -fb-create.
The commonly used prefix is "fbdata".
The same optimization flags should be used
for both the -fb-create and fb_opt compile steps.
Feedback data files created from executables compiled
with different optimization flags may give checksum errors.
FDO is OFF by default.
During the -fb_opt compilation phase, information regarding execution paths and data values are used to improve the information available to the optimizer. FDO enables some optimizations which are only performed when the feedback data file is available. The safety of optimizations performed under FDO is consistent with the level of safety implied by the other optimization flags (outside of fb_create and fb_opt) specified on the compile and link lines.
Equivalent to -O3 -ipa -OPT:Ofast -fno-math-errno -ffast-math.
Use optimizations selected to maximize performance.
Although the optimizations are generally safe, they may affect
floating point accuracy due to rearrangement of computations.
NOTE: -Ofast enables -ipa (inter-procedural analysis), which places limitations on how libraries and .o files are built.
-IPA:plimit=N : This option stops inlining into a specific subprogram once it reaches size N in the intermediate representation. Default is 2500.
This option controls the LNO optimization level. The options can be
one of the following:
0 = Disable nearly all loop nest optimizations.
1 = Perform full loop nest transformations. This is the default.
-WOPT:if_conv=(0|1|2):
Controls the optimization that translates simple IF
statements to conditional move instructions in the
target CPU. Setting to 0 suppresses this optimization.
The value of 1 designates conservative if-conversion,
in which the context around the IF statement is used
in deciding whether to if-convert. The value of 2
enables aggressive if-conversion by causing it to be
performed regardless of the context. The default is 1.
-CG:local_sched_alg : Select the basic block instruction scheduling algorithm. If 0, perform backward scheduling, where instructions are scheduled from the bottom of the basic block to the top. If 1, perform forward scheduling. If 2, schedule the instructions twice - once in the forward direction and once in the backward direction - and take the better of the two schedules. The default value of this option is determined by the compiler during compilation.
Generate profile-feedback instrumentation (PFI); this includes extra code to collect run-time statistics and dump them to a trace file for use in a subsequent compilation. PFI gathers information about a program's execution and data values but does not gather information from hardware performance counters. PFI does gather data for optimizations which are unique to profile-feedback optimization.
The indirect sub-option enables collection of indirect function call targets, which can be used for indirect function call inlining.
Enable profile-feedback optimizations including indirect function call inlining. This option requires a pgfi.out file generated from a binary built with -Mpfi=indirect.
Chooses generally optimal flags for the target platform. As of the PGI 7.0 release, the flags "-fast" and "-fastsse" are equivlent for 64-bit compilations. For 32-bit compilations "-fast" does not include "-Mscalarsse", "-Mcache_align", or "-Mvect=sse".
Link with the huge page runtime library and allocate a maximum of 150 huge pages where 150 is a supplied constant value. If no constant value is supplied, then the maximum number of huge pages the application can use is limited by the number of huge pages the operating system has available or the value of the environment variable PGI_HUGE_PAGES.
Note that setting PGI_HUGE_PAGES will override the value of 150. This environment variable is described below in the section "System and Other Tuning Information".
Use the prefetcht0 instruction.
Disable loop unrolling.
Specify the type of the target processor as AMD64 Barcelona Processor 64-bit mode.
Staticily link with the PGI runtime libraries. System libraries may still be dynamically linked.
-march=<cpu-type>
Compiler will optimize code for selected cpu-type:
opteron, athlon, athlon64, athlon64fx, barcelona, em64t,
pentium4, xeon, core, anyx86, auto.
The default value, auto, means to optimize for the platform
on which the compiler is running,
as determined by reading /proc/cpuinfo.
anyx86 means a generic 32-bit x86 processor
without SSE2 support.
barcelona is AMD's first Quad-core processor family.
-fb_create <path>
Used to specify that an instrumented executable program is to be
generated. Such an executable is suitable for producing feedback
data files with the specified prefix for use in feedback-directed
optimization (FDO).
The commonly used prefix is "fbdata".
This is OFF by default.
During the training run, the instrumented executable produces information regarding execution paths and data values, but does not generate information by using hardware performance counters.
-fb_opt <prefix for feedback data files>
Used to specify feedback-directed optimization (FDO) by extracting
feedback data from files with the specified prefix, which were
previously generated using -fb-create.
The commonly used prefix is "fbdata".
The same optimization flags should be used
for both the -fb-create and fb_opt compile steps.
Feedback data files created from executables compiled
with different optimization flags may give checksum errors.
FDO is OFF by default.
During the -fb_opt compilation phase, information regarding execution paths and data values are used to improve the information available to the optimizer. FDO enables some optimizations which are only performed when the feedback data file is available. The safety of optimizations performed under FDO is consistent with the level of safety implied by the other optimization flags (outside of fb_create and fb_opt) specified on the compile and link lines.
Specify the basic level of optimization desired.
The options can be one of the following:
0 Turn off all optimizations.
1 Turn on local optimizations that can be done quickly. Do peephole optimizations and instruction scheduling.
2 Turn on extensive optimization.
This is the default.
The optimizations at this level are generally conservative,
in the sense that they are virtually always beneficial and
avoid changes which affect
such things as floating point accuracy. In addition to the level
1 optimizations, do inner loop
unrolling, if-conversion, two passes of instruction scheduling,
global register allocation, dead store elimination,
instruction scheduling across basic blocks,
and partial redundancy elimination.
3 Turn on aggressive optimization.
The optimizations at this level are distinguished from -O2
by their aggressiveness, generally seeking highest-quality
generated code even if it requires extensive compile time.
They may include optimizations that are generally beneficial
but may hurt performance.
This includes but is not limited to turning on the
Loop Nest Optimizer, -LNO:opt=1, and setting
-OPT:roundoff=1:IEEE_arithmetic=2:Olimit=9000:reorg_common=ON.
s Specify that code size is to be given priority in tradeoffs with execution time.
If no value is specified, 2 is assumed.-OPT:Ofast
Use optimizations selected to maximize performance.
Although the optimizations are generally safe, they may affect
floating point accuracy due to rearrangement of computations.
This effectively turns on the following optimizations:
-OPT:ro=2:Olimit=0:div_split=ON:alias=typed:malloc_alg=1.
Compile for 32-bit ABI, also known as x86 or IA32.
Chooses generally optimal flags for the target platform. As of the PGI 7.0 release, the flags "-fast" and "-fastsse" are equivlent for 64-bit compilations. For 32-bit compilations "-fast" does not include "-Mscalarsse", "-Mcache_align", or "-Mvect=sse".
Link with the huge page runtime library and allocate a maximum of 150 huge pages where 150 is a supplied constant value. If no constant value is supplied, then the maximum number of huge pages the application can use is limited by the number of huge pages the operating system has available or the value of the environment variable PGI_HUGE_PAGES.
Note that setting PGI_HUGE_PAGES will override the value of 150. This environment variable is described below in the section "System and Other Tuning Information".
Interprocedural Analysis option: Specifies the number of concurent IPA second pass compliation proccess that may be performed. This option speeds-up the compilation time on multi-core systems but does not perform any optimizations.
Instructs the compiler to perform interprocedural analysis. Equivalant to -Mipa=align,arg,const,f90ptr,shape,globals,libc,localarg,ptr,pure.
Interprocedural Analysis option: Automatically determine which functions to inline, limit to 1 levels where 1 is a supplied constant value. If no value is suppiled, then the default value of 2 is used. IPA-based function inlining is performed from leaf routines upward.
Specify the type of the target processor as AMD64 Barcelona Processor 32-bit mode.
Staticily link with the PGI runtime libraries. System libraries may still be dynamically linked.
-march=<cpu-type>
Compiler will optimize code for selected cpu-type:
opteron, athlon, athlon64, athlon64fx, barcelona, em64t,
pentium4, xeon, core, anyx86, auto.
The default value, auto, means to optimize for the platform
on which the compiler is running,
as determined by reading /proc/cpuinfo.
anyx86 means a generic 32-bit x86 processor
without SSE2 support.
barcelona is AMD's first Quad-core processor family.
-fb_create <path>
Used to specify that an instrumented executable program is to be
generated. Such an executable is suitable for producing feedback
data files with the specified prefix for use in feedback-directed
optimization (FDO).
The commonly used prefix is "fbdata".
This is OFF by default.
During the training run, the instrumented executable produces information regarding execution paths and data values, but does not generate information by using hardware performance counters.
-fb_opt <prefix for feedback data files>
Used to specify feedback-directed optimization (FDO) by extracting
feedback data from files with the specified prefix, which were
previously generated using -fb-create.
The commonly used prefix is "fbdata".
The same optimization flags should be used
for both the -fb-create and fb_opt compile steps.
Feedback data files created from executables compiled
with different optimization flags may give checksum errors.
FDO is OFF by default.
During the -fb_opt compilation phase, information regarding execution paths and data values are used to improve the information available to the optimizer. FDO enables some optimizations which are only performed when the feedback data file is available. The safety of optimizations performed under FDO is consistent with the level of safety implied by the other optimization flags (outside of fb_create and fb_opt) specified on the compile and link lines.
Specify the basic level of optimization desired.
The options can be one of the following:
0 Turn off all optimizations.
1 Turn on local optimizations that can be done quickly. Do peephole optimizations and instruction scheduling.
2 Turn on extensive optimization.
This is the default.
The optimizations at this level are generally conservative,
in the sense that they are virtually always beneficial and
avoid changes which affect
such things as floating point accuracy. In addition to the level
1 optimizations, do inner loop
unrolling, if-conversion, two passes of instruction scheduling,
global register allocation, dead store elimination,
instruction scheduling across basic blocks,
and partial redundancy elimination.
3 Turn on aggressive optimization.
The optimizations at this level are distinguished from -O2
by their aggressiveness, generally seeking highest-quality
generated code even if it requires extensive compile time.
They may include optimizations that are generally beneficial
but may hurt performance.
This includes but is not limited to turning on the
Loop Nest Optimizer, -LNO:opt=1, and setting
-OPT:roundoff=1:IEEE_arithmetic=2:Olimit=9000:reorg_common=ON.
s Specify that code size is to be given priority in tradeoffs with execution time.
If no value is specified, 2 is assumed.The -OPT: option group controls miscellaneous optimizations. These options override defaults based on the main optimization level.
-OPT:alias=<name>
Specify the pointer aliasing model
to be used. By specifying one or more of the following for <name>,
the compiler is able to make assumptions throughout the compilation:
typed
Assume that the code adheres to the ANSI/ISO C standard
which states that two pointers of different types cannot point
to the same location in memory.
This is ON by default when -OPT:Ofast is specified.
restrict
Specify that distinct pointers are assumed to point to distinct,
non-overlapping objects. This is OFF by default.
disjoint
Specify that any two pointer expressions are assumed to point
to distinct, non-overlapping objects. This is OFF by default.
no_f90_pointer_alias
Specify that any two Fortran 90 pointer expressions are assumed to point
to distinct, non-overlapping objects. This is OFF by default.
-LNO:prefetch=(0|1|2|3) : This option specifies the level of prefetching.
0 = Prefetch disabled.
1 = Prefetch is done only for arrays that are always referenced in each iteration of a loop.
2 = Prefetch is done without the above restriction. This is the default.
3 = Most aggressive.
-LNO:ignore_feedback=(on|off|0|1) : If the flag is ON then feedback information from the loop annotations will be ignored in LNO transformations. The default is OFF.
-CG:p2align : Align loop heads to 64-byte boundaries. The default is off.
Chooses generally optimal flags for the target platform. As of the PGI 7.0 release, the flags "-fast" and "-fastsse" are equivlent for 64-bit compilations. For 32-bit compilations "-fast" does not include "-Mscalarsse", "-Mcache_align", or "-Mvect=sse".
Instructs the vectorizer to generate partial vectorization.
"-Munroll=n:n" instructs the compiler to unroll loops 8 times where 8 is a supplied constant value. If no constant value is given, then a default of 4 is used.
Link with the huge page runtime library and allocate a maximum of 150 huge pages where 150 is a supplied constant value. If no constant value is supplied, then the maximum number of huge pages the application can use is limited by the number of huge pages the operating system has available or the value of the environment variable PGI_HUGE_PAGES.
Note that setting PGI_HUGE_PAGES will override the value of 150. This environment variable is described below in the section "System and Other Tuning Information".
Instructs the C/C++ compiler to override data dependencies between pointers of a given storage class.
Use the prefetcht0 instruction.
Instructs the compiler to use relaxed precision in the calculation of some intrinsic functions. Can result in improved performance at the expense of numerical accuracy. The default on an AMD system is "-Mfprelaxed=sqrt,rsqrt,order". The default on an Intel system is "-Mfprelaxed=rsqrt,sqrt,div,order"
Interprocedural Analysis option: Specifies the number of concurent IPA second pass compliation proccess that may be performed. This option speeds-up the compilation time on multi-core systems but does not perform any optimizations.
Interprocedural Analysis option: Enable interprocedural constant propagation.
Interprocedural Analysis option: Enable pointer disambiguation across procedure calls.
Interprocedural Analysis option: Remove arguments replaced by -Mipa=ptr,const
Interprocedural Analysis option: Automatically determine which functions to inline, limit to 2 levels (default). IPA-based function inlining is performed from leaf routines upward.
Specify the type of the target processor as AMD64 Barcelona Processor 64-bit mode.
Staticily link with the PGI runtime libraries. System libraries may still be dynamically linked.
Generate profile-feedback instrumentation (PFI); this includes extra code to collect run-time statistics and dump them to a trace file for use in a subsequent compilation. PFI gathers information about a program's execution and data values but does not gather information from hardware performance counters. PFI does gather data for optimizations which are unique to profile-feedback optimization.
Enable profile-feedback optimizations.
Interprocedural Analysis option: Specifies the number of concurent IPA second pass compliation proccess that may be performed. This option speeds-up the compilation time on multi-core systems but does not perform any optimizations.
Instructs the compiler to perform interprocedural analysis. Equivalant to -Mipa=align,arg,const,f90ptr,shape,globals,libc,localarg,ptr,pure.
Interprocedural Analysis option: Automatically determine which functions to inline, limit to 1 levels where 1 is a supplied constant value. If no value is suppiled, then the default value of 2 is used. IPA-based function inlining is performed from leaf routines upward.
Interprocedural Analysis option: Do not remove arguments replaced by -Mipa=ptr,const
Chooses generally optimal flags for the target platform. As of the PGI 7.0 release, the flags "-fast" and "-fastsse" are equivlent for 64-bit compilations. For 32-bit compilations "-fast" does not include "-Mscalarsse", "-Mcache_align", or "-Mvect=sse".
Link with the huge page runtime library and allocate a maximum of 150 huge pages where 150 is a supplied constant value. If no constant value is supplied, then the maximum number of huge pages the application can use is limited by the number of huge pages the operating system has available or the value of the environment variable PGI_HUGE_PAGES.
Note that setting PGI_HUGE_PAGES will override the value of 150. This environment variable is described below in the section "System and Other Tuning Information".
Instructs the compiler to use relaxed precision in the calculation of some intrinsic functions. Can result in improved performance at the expense of numerical accuracy. The default on an AMD system is "-Mfprelaxed=sqrt,rsqrt,order". The default on an Intel system is "-Mfprelaxed=rsqrt,sqrt,div,order"
Specify the type of the target processor as AMD64 Barcelona Processor 64-bit mode.
Staticily link with the PGI runtime libraries. System libraries may still be dynamically linked.
Chooses generally optimal flags for the target platform. As of the PGI 7.0 release, the flags "-fast" and "-fastsse" are equivlent for 64-bit compilations. For 32-bit compilations "-fast" does not include "-Mscalarsse", "-Mcache_align", or "-Mvect=sse".
"-Munroll=m:n" instructs the compiler to unroll loops with multiple blocks 8 times where 8 is a supplied constant value. If no constant value is given, then a default of 4 is used.
Link with the huge page runtime library and allocate a maximum of 150 huge pages where 150 is a supplied constant value. If no constant value is supplied, then the maximum number of huge pages the application can use is limited by the number of huge pages the operating system has available or the value of the environment variable PGI_HUGE_PAGES.
Note that setting PGI_HUGE_PAGES will override the value of 150. This environment variable is described below in the section "System and Other Tuning Information".
Set the fetch-ahead distance for prefetch instructions to 4 cache lines
Instructs the compiler to use relaxed precision in the calculation of some intrinsic functions. Can result in improved performance at the expense of numerical accuracy. The default on an AMD system is "-Mfprelaxed=sqrt,rsqrt,order". The default on an Intel system is "-Mfprelaxed=rsqrt,sqrt,div,order"
Interprocedural Analysis option: Specifies the number of concurent IPA second pass compliation proccess that may be performed. This option speeds-up the compilation time on multi-core systems but does not perform any optimizations.
Instructs the compiler to perform interprocedural analysis. Equivalant to -Mipa=align,arg,const,f90ptr,shape,globals,libc,localarg,ptr,pure.
Interprocedural Analysis option: Automatically determine which functions to inline, limit to 2 levels (default). IPA-based function inlining is performed from leaf routines upward.
Interprocedural Analysis option: Do not remove arguments replaced by -Mipa=ptr,const
Specify the type of the target processor as AMD64 Barcelona Processor 64-bit mode.
Staticily link with the PGI runtime libraries. System libraries may still be dynamically linked.
-march=<cpu-type>
Compiler will optimize code for selected cpu-type:
opteron, athlon, athlon64, athlon64fx, barcelona, em64t,
pentium4, xeon, core, anyx86, auto.
The default value, auto, means to optimize for the platform
on which the compiler is running,
as determined by reading /proc/cpuinfo.
anyx86 means a generic 32-bit x86 processor
without SSE2 support.
barcelona is AMD's first Quad-core processor family.
-fb_create <path>
Used to specify that an instrumented executable program is to be
generated. Such an executable is suitable for producing feedback
data files with the specified prefix for use in feedback-directed
optimization (FDO).
The commonly used prefix is "fbdata".
This is OFF by default.
During the training run, the instrumented executable produces information regarding execution paths and data values, but does not generate information by using hardware performance counters.
-fb_opt <prefix for feedback data files>
Used to specify feedback-directed optimization (FDO) by extracting
feedback data from files with the specified prefix, which were
previously generated using -fb-create.
The commonly used prefix is "fbdata".
The same optimization flags should be used
for both the -fb-create and fb_opt compile steps.
Feedback data files created from executables compiled
with different optimization flags may give checksum errors.
FDO is OFF by default.
During the -fb_opt compilation phase, information regarding execution paths and data values are used to improve the information available to the optimizer. FDO enables some optimizations which are only performed when the feedback data file is available. The safety of optimizations performed under FDO is consistent with the level of safety implied by the other optimization flags (outside of fb_create and fb_opt) specified on the compile and link lines.
Specify the basic level of optimization desired.
The options can be one of the following:
0 Turn off all optimizations.
1 Turn on local optimizations that can be done quickly. Do peephole optimizations and instruction scheduling.
2 Turn on extensive optimization.
This is the default.
The optimizations at this level are generally conservative,
in the sense that they are virtually always beneficial and
avoid changes which affect
such things as floating point accuracy. In addition to the level
1 optimizations, do inner loop
unrolling, if-conversion, two passes of instruction scheduling,
global register allocation, dead store elimination,
instruction scheduling across basic blocks,
and partial redundancy elimination.
3 Turn on aggressive optimization.
The optimizations at this level are distinguished from -O2
by their aggressiveness, generally seeking highest-quality
generated code even if it requires extensive compile time.
They may include optimizations that are generally beneficial
but may hurt performance.
This includes but is not limited to turning on the
Loop Nest Optimizer, -LNO:opt=1, and setting
-OPT:roundoff=1:IEEE_arithmetic=2:Olimit=9000:reorg_common=ON.
s Specify that code size is to be given priority in tradeoffs with execution time.
If no value is specified, 2 is assumed.-IPA:plimit=N : This option stops inlining into a specific subprogram once it reaches size N in the intermediate representation. Default is 2500.
The -OPT: option group controls miscellaneous optimizations. These options override defaults based on the main optimization level.
-OPT:alias=<name>
Specify the pointer aliasing model
to be used. By specifying one or more of the following for <name>,
the compiler is able to make assumptions throughout the compilation:
typed
Assume that the code adheres to the ANSI/ISO C standard
which states that two pointers of different types cannot point
to the same location in memory.
This is ON by default when -OPT:Ofast is specified.
restrict
Specify that distinct pointers are assumed to point to distinct,
non-overlapping objects. This is OFF by default.
disjoint
Specify that any two pointer expressions are assumed to point
to distinct, non-overlapping objects. This is OFF by default.
no_f90_pointer_alias
Specify that any two Fortran 90 pointer expressions are assumed to point
to distinct, non-overlapping objects. This is OFF by default.
-LNO:prefetch=(0|1|2|3) : This option specifies the level of prefetching.
0 = Prefetch disabled.
1 = Prefetch is done only for arrays that are always referenced in each iteration of a loop.
2 = Prefetch is done without the above restriction. This is the default.
3 = Most aggressive.
-CG:ptr_load_use=N: Add a latency of N cycles between an instruction that loads a pointer and an instruction that uses the pointer. The extra latency will force the instruction scheduler to schedule the pointer load earlier. In general, it is beneficial to load pointers as soon as possible so that dependent memory instructions can begin execution. N is 4 by default. ("Load pointer" instructions include load-execute instructions that compute a pointer result.)
-CG:push_pop_int_saved_regs: Use the X86 push and pop instructions to save the integer callee-saved registers at function prologs and epilogs instead of mov instructions to and from memory locations based off the stack pointer. The default is ON when the CPU target is barcelona, and OFF otherwise.
Generate profile-feedback instrumentation (PFI); this includes extra code to collect run-time statistics and dump them to a trace file for use in a subsequent compilation. PFI gathers information about a program's execution and data values but does not gather information from hardware performance counters. PFI does gather data for optimizations which are unique to profile-feedback optimization.
Enable profile-feedback optimizations.
Interprocedural Analysis option: Specifies the number of concurent IPA second pass compliation proccess that may be performed. This option speeds-up the compilation time on multi-core systems but does not perform any optimizations.
Instructs the compiler to perform interprocedural analysis. Equivalant to -Mipa=align,arg,const,f90ptr,shape,globals,libc,localarg,ptr,pure.
Interprocedural Analysis option: Automatically determine which functions to inline, limit to 6 levels where 6 is a supplied constant value. If no value is suppiled, then the default value of 2 is used. IPA-based function inlining is performed from leaf routines upward.
Chooses generally optimal flags for the target platform. As of the PGI 7.0 release, the flags "-fast" and "-fastsse" are equivlent for 64-bit compilations. For 32-bit compilations "-fast" does not include "-Mscalarsse", "-Mcache_align", or "-Mvect=sse".
Link with the huge page runtime library and allocate a maximum of 150 huge pages where 150 is a supplied constant value. If no constant value is supplied, then the maximum number of huge pages the application can use is limited by the number of huge pages the operating system has available or the value of the environment variable PGI_HUGE_PAGES.
Note that setting PGI_HUGE_PAGES will override the value of 150. This environment variable is described below in the section "System and Other Tuning Information".
Instructs the compiler that global or external pointers and arrays do not overlap or conflict with each other and are independent.
Instructs the compiler to use relaxed precision in the calculation of some intrinsic functions. Can result in improved performance at the expense of numerical accuracy. The default on an AMD system is "-Mfprelaxed=sqrt,rsqrt,order". The default on an Intel system is "-Mfprelaxed=rsqrt,sqrt,div,order"
Generate zero-overhead C++ exception handlers.
Specify the type of the target processor as AMD64 Barcelona Processor 32-bit mode.
Staticily link with the PGI runtime libraries. System libraries may still be dynamically linked.
-march=<cpu-type>
Compiler will optimize code for selected cpu-type:
opteron, athlon, athlon64, athlon64fx, barcelona, em64t,
pentium4, xeon, core, anyx86, auto.
The default value, auto, means to optimize for the platform
on which the compiler is running,
as determined by reading /proc/cpuinfo.
anyx86 means a generic 32-bit x86 processor
without SSE2 support.
barcelona is AMD's first Quad-core processor family.
Equivalent to -O3 -ipa -OPT:Ofast -fno-math-errno -ffast-math.
Use optimizations selected to maximize performance.
Although the optimizations are generally safe, they may affect
floating point accuracy due to rearrangement of computations.
NOTE: -Ofast enables -ipa (inter-procedural analysis), which places limitations on how libraries and .o files are built.
-OPT:unroll_times_max=N
Unroll inner loops by a maximum of N. The default is 4.
-CG:push_pop_int_saved_regs: Use the X86 push and pop instructions to save the integer callee-saved registers at function prologs and epilogs instead of mov instructions to and from memory locations based off the stack pointer. The default is ON when the CPU target is barcelona, and OFF otherwise.
-CG:ptr_load_use=N: Add a latency of N cycles between an instruction that loads a pointer and an instruction that uses the pointer. The extra latency will force the instruction scheduler to schedule the pointer load earlier. In general, it is beneficial to load pointers as soon as possible so that dependent memory instructions can begin execution. N is 4 by default. ("Load pointer" instructions include load-execute instructions that compute a pointer result.)
Compile for 32-bit ABI, also known as x86 or IA32.
Link using MicroQuill's SmartHeap 8 (32-bit) library for Linux. Description from Microquill:
SmartHeap is a fast (3X-100X faster than compiler-supplied libraries), portable (Windows, Linux, Solaris, HP-UX, IBM-AIX, Dec OSF Tru64, SGI Irix), reliable, ANSI-compliant malloc/operator new library. SmartHeap supports multiple memory pools, includes a fixed-size allocator, and is thread-safe. SmartHeap also includes comprehensive memory debugging APIs to detect leakage, overwrites, double-frees, wild pointers, out of memory, references to previously freed memory, and other memory errors.
Specifies a directory to search for libraries. Use -L to add directories to the search path for library files. Multiple -L options are valid. However, the position of multiple -L options is important relative to -l options supplied.
This section contains descriptions of flags that were included implicitly by other flags, but which do not have a permanent home at SPEC.
Level-two optimization (-O2 or -O) specifies global optimization. The -fast option generally will specify global optimization; however, the -fast switch will vary from release to release depending on a reasonable selection of switches for any one particular release. The -O or -O2 level performs all level-one local optimizations as well as global optimizations. Control flow analysis is applied and global registers are allocated for all functions and subroutines. Loop regions are given special consideration. This optimization level is a good choice when the program contains loops, the loops are short, and the structure of the code is regular.
The PGI compilers perform many different types of global optimizations, including but not limited to:
Level-one optimization specifies local optimization (-O1). The compiler performs scheduling of basic blocks as well as register allocation. This optimization level is a good choice when the code is very irregular; that is it contains many short statements containing IF statements and the program does not contain loops (DO or DO WHILE statements). For certain types of code, this optimization level may perform better than level-two (-O2) although this case rarely occurs.
The PGI compilers perform many different types of local optimizations, including but not limited to:
Instructs the compiler to completely unroll loops with a constant loop count of less than or equal to 1 where 1 is a supplied constant value. If no constant value is given, then a default of 4 is used.
Invokes the loop unroller.
Inline functions declared with the inline keyword.
Enable an optional post-pass instruction scheduling.
Enables loop-carried redundancy elimination, an optimization that can reduce the number of arithmetic operations and memory references in loops.
Eliminates operations that set up a true stack frame pointer for every function. With this option enabled, you cannot perform a traceback on the generated code and you cannot access local variables.
Instructs the vectorizer to search for vectorizable loops and, where possible, make use of SSE, SSE2, and prefetch instructions.
Enable automatic vector pipelining.
Instructs the vectorizer to enable certain associativity conversions that can change the results of a computations due to roundoff error. A typical optimization is to change an arithmetic operation to an arithmetic opteration that is mathmatically correct, but can be computationally different, due to round-off error.
Instructs the vectorizer to generate alternate code for vectorized loops when appropriate. For each vectorized loop the compiler decides whether to generate altcode and what type or types to generate, which may be any or all of:
The compiler also determines suitable loop count and array alignment conditions for executing the altcode.
Align "unconstrained" data objects of size greater than or equal to 16 bytes on cache-line boundaries. An "unconstrained" object is a variable or array that is not a member of an aggregate structure or common block, is not allocatable, and is not an automatic array. On by default on 64-bit Linux systems.
Set SSE to flush-to-zero mode; if a floating-point underflow occurs, the value is set to zero.
Treat denormalized numbers as zero. Included with "-fast" on Intel based systems. For AMD based systems, "-Mdaz" is not included by default with "-fast".
Use SSE/SSE2 instructions to perform scalar floating-point arithmetic on targets where these instructions are supported.
Instructs the compiler to use relaxed precision in the calculation of floating-point reciprocal square root (1/sqrt). Can result in improved performance at the expense of numerical accuracy.
Instructs the compiler to use relaxed precision in the calculation of floating-point square root. Can result in improved performance at the expense of numerical accuracy.
Instructs the compiler to use relaxed precision in the calculation of floating-point division. Can result in improved performance at the expense of numerical accuracy.
Instructs the compiler to allow floating-point expression reordering, including factoring. Can result in improved performance at the expense of numerical accuracy.
Interprocedural Analysis option: Recognize when targets of pointer dummy are aligned.
Interprocedural Analysis option: Remove arguments replaced by -Mipa=ptr,const
Interprocedural Analysis option: Enable pointer disambiguation across procedure calls.
Interprocedural Analysis option: Enable interprocedural constant propagation.
Interprocedural Analysis option: Fortran 90/95 Pointer disambiguation across calls.
Interprocedural Analysis option: Perform Fortran 90 array shape propagation.
Interprocedural Analysis option: Optimize references to global values.
Interprocedural Analysis option: Used to optimize calls to certain functions in the system standard C library, libc.
Interprocedural Analysis option: -Mipa=arg plus externalizes local pointer targets.
Interprocedural Analysis option: Pure function detection.
Specify the basic level of optimization desired.
The options can be one of the following:
0 Turn off all optimizations.
1 Turn on local optimizations that can be done quickly. Do peephole optimizations and instruction scheduling.
2 Turn on extensive optimization.
This is the default.
The optimizations at this level are generally conservative,
in the sense that they are virtually always beneficial and
avoid changes which affect
such things as floating point accuracy. In addition to the level
1 optimizations, do inner loop
unrolling, if-conversion, two passes of instruction scheduling,
global register allocation, dead store elimination,
instruction scheduling across basic blocks,
and partial redundancy elimination.
3 Turn on aggressive optimization.
The optimizations at this level are distinguished from -O2
by their aggressiveness, generally seeking highest-quality
generated code even if it requires extensive compile time.
They may include optimizations that are generally beneficial
but may hurt performance.
This includes but is not limited to turning on the
Loop Nest Optimizer, -LNO:opt=1, and setting
-OPT:roundoff=1:IEEE_arithmetic=2:Olimit=9000:reorg_common=ON.
s Specify that code size is to be given priority in tradeoffs with execution time.
If no value is specified, 2 is assumed.Invoke inter-procedural analysis (IPA). Specifying this option is identical to specifying -IPA or -IPA:. Default settings for the individual IPA suboptions are used.
-OPT:Ofast
Use optimizations selected to maximize performance.
Although the optimizations are generally safe, they may affect
floating point accuracy due to rearrangement of computations.
This effectively turns on the following optimizations:
-OPT:ro=2:Olimit=0:div_split=ON:alias=typed:malloc_alg=1.
-OPT:roundoff,ro=(0|1|2|3)
Specify the level of acceptable departure from source language
floating-point, round-off, and overflow semantics.
The options can be one of the following:
0 = Inhibit optimizations that might affect the floating-point behavior. This is the default when optimization levels -O0, -O1, and -O2 are in effect.
1 = Allow simple transformations that might cause limited round-off or overflow differences. Compounding such transformations could have more extensive effects. This is the default when -O3 is in effect.
2 = Allow more extensive transformations, such as the reordering of reduction loops. This is the default level when -OPT:Ofast is specified.
3 = Enable any mathematically valid transformation.
-OPT:Olimit=N
Disable optimization when size of program unit is > N. When N is 0,
program unit size is ignored and optimization process will not be
disabled due to compile time limit.
The default is 0 when -OPT:Ofast is specified,
9000 when -O3 is specified; otherwise the default is 6000.
-OPT:div_split=(ON|OFF)
Enable or disable changing x/y into x*(recip(y)). This is OFF by
default, but enabled by -OPT:Ofast or -OPT:IEEE_arithmetic=3.
This transformation generates fairly accurate code.
The -OPT: option group controls miscellaneous optimizations. These options override defaults based on the main optimization level.
-OPT:alias=<name>
Specify the pointer aliasing model
to be used. By specifying one or more of the following for <name>,
the compiler is able to make assumptions throughout the compilation:
typed
Assume that the code adheres to the ANSI/ISO C standard
which states that two pointers of different types cannot point
to the same location in memory.
This is ON by default when -OPT:Ofast is specified.
restrict
Specify that distinct pointers are assumed to point to distinct,
non-overlapping objects. This is OFF by default.
disjoint
Specify that any two pointer expressions are assumed to point
to distinct, non-overlapping objects. This is OFF by default.
no_f90_pointer_alias
Specify that any two Fortran 90 pointer expressions are assumed to point
to distinct, non-overlapping objects. This is OFF by default.
-OPT:malloc_alg=(0|1)
Select an alternate malloc algorithm which may improve speed.
The compiler adds setup code in the
C/C++/Fortran "main" function to enable the chosen algorithm.
The default is 1 when -OPT:Ofast is specified. Otherwise, the default
is 0.
Do not set ERRNO after calling math functions that are executed with a single instruction, e.g. sqrt. A program that relies on IEEE exceptions for math error handling may want to use this flag for speed while maintaining IEEE arithmetic compatibility. This is implied by -Ofast. The default is -fmath-errno.
-ffast-math improves FP speed by relaxing ANSI & IEEE rules. -fno-fast-math tells the compiler to conform to ANSI and IEEE math rules at the expense of speed. -ffast- math implies -OPT:IEEE_arithmetic=2 -fno-math-errno. -fno-fast-math implies -OPT:IEEE_arithmetic=1 -fmath-errno.
Enable generation of prefetch instructions on processors where they are supported.
Instructs the C/C++ compiler to override data dependencies between pointers of a given storage class.
One or more of the following settings may have been set. If so, the corresponding notes sections of the report will say so; and you can read below to find out more about what these settings mean.
Environment Variables
MP_BIND
This Environment Variable controls the runtime behavior
of binaries compiled with the PGI compilers.
It can be set to yes or y
to bind processes or threads executing in a parallel region
to physical processors, or to no or n to disable such binding.
The default is to not bind processes to processors.
This is an execution time environment variable interpreted by the
PGI runtime support libraries. It does not affect the behavior
of the PGI compilers in any way. Note: the MP_BIND
environment variable is not supported on all platforms.
MP_BLIST
This Environment Variable controls the runtime behavior
of binaries compiled with the PGI compilers.
In addition to the MP_BIND variable, it is possible to define
the thread-CPU relationship.
For example, setting MP_BLIST=3,2,1,0 maps CPUs 3, 2, 1 and 0
to threads 0, 1, 2 and 3 respectively.
OMP_NUM_THREADS
This Environment Variable controls the runtime behavior
of binaries compiled with the PGI and PathScale compilers.
This Environment Variable
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
Default is the number of cores visible to the OS.
PGI_HUGE_PAGES
This Environment Variable controls the runtime behavior
of binaries compiled with the PGI compilers.
The maximum number of huge pages an application is allowed
to use can be set at run time via the environment variable
PGI_HUGE_PAGES. If not set, then the process may use all
available huge pages when compiled with "-Msmartalloc=huge"
or a maximum of n pages where the value of n
is set via the compile time flag "-Msmartalloc=huge:n."
KMP_AFFINITY
KMP_AFFINITY = < physical | logical >, starting-core-id
This Environment Variable
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.
Linux commands
ulimit -s < n | unlimited >
This Linux command (a bash builtin command) sets the stack size to n kbytes, or unlimited to allow the stack size to grow without limit.
ulimit -l < n | unlimited >
This Linux command (a bash builtin command) sets the maximum size of memory that may be locked into physical memory.
numactl -m nodes --physcpubind=cpus command
numactl runs processes with a specific NUMA scheduling or memory placement policy. The policy is set for command and inherited by all of its children. The arguments used here are:
numactl has many more options which are not described here since they are not used.
SPEC config file feature submit
submit = echo "$command" >run.sh ; $BIND bash run.sh
When running multiple copies of benchmarks, the SPEC config file feature submit is sometimes used to cause individual jobs to be bound to specific processors. This specific submit command is used for Linux. The description of the elements of the command are:
bind0 = numactl -m 0 --physcpubind=0 bind1 = numactl -m 0 --physcpubind=1 bind2 = numactl -m 0 --physcpubind=2 bind3 = numactl -m 0 --physcpubind=3 bind4 = numactl -m 1 --physcpubind=4 bind5 = numactl -m 1 --physcpubind=5 bind6 = numactl -m 1 --physcpubind=6 bind7 = numactl -m 1 --physcpubind=7
In this example, the first benchmark instance
uses bind0, so "$BIND bash runsh" is expanded to become "numactl -m
0 --physcpubind=0 bash run.sh". The second instance uses bind1, and
so on.
If there are more copies than bind values, they
will be re-used in a circular fashion. If there are more bind values
specified than copies, then only as many as needed will be used.
Linux Huge Page settings
In order to take full advantage of using PGI's huge page runtime library, your system must be configured to use huge pages. It is safe to run binaries compiled with "-Msmartalloc=huge" on systems not configured to use huge pages, however, you will not benefit from the performance improvements huge pages offer. To configure your system for huge pages perform the following steps:
Note that further information about huge pages may be found in your Linux documentation file: /usr/src/linux/Documentation/vm/hugetlbpage.txt
Flag description origin markings:
|
Indicates that the flag description came from the user flags file. |
|
Indicates that the flag description came from the suite-wide flags file. |
|
Indicates that the flag description came from a per-benchmark flags file. |
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 v1.0.
Report generated on Tue Jul 22 19:59:18 2014 by SPEC CPU2006 flags formatter v6906.