This result has been formatted using multiple flags files. The "default header section" from each of them appears next.
Note: The GNU Compiler Collection provides a wide array of compiler options, described in detail and readily available at https://gcc.gnu.org/onlinedocs/gcc/Option-Index.html#Option-Index and https://gcc.gnu.org/onlinedocs/gfortran/. This SPEC CPU flags file contains excerpts from and brief summaries of portions of that documentation.
SPEC's modifications are:
Copyright (C) 2006-2017 Standard Performance Evaluation Corporation
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being "Funding Free Software", the Front-Cover Texts being (a) (see below), and with the Back-Cover Texts being (b) (see below). A copy of the license is included in your SPEC CPU kit at $SPEC/Docs/licenses/FDL.v1.3 and on the web at http://www.spec.org/cpu2017/Docs/licenses/FDL.v1.3. A copy of "Funding Free Software" is on your SPEC CPU kit at $SPEC/Docs/licenses/FundingFreeSW and on the web at http://www.spec.org/cpu2017/Docs/licenses/FundingFreeSW.
(a) The FSF's Front-Cover Text is:
A GNU Manual
(b) The FSF's Back-Cover Text is:
You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development.
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking. Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking. Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
Invoke the GNU Fortran compiler with the optimizers and code generators replaced by those from AOCC. The "dragonegg.so" referenced here is the "AOCC Fortran Plugin".
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking. Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
Invoke the GNU Fortran compiler with the optimizers and code generators replaced by those from AOCC. The "dragonegg.so" referenced here is the "AOCC Fortran Plugin".
clang++ C++ compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking. Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking. Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
Invoke the GNU Fortran compiler with the optimizers and code generators replaced by those from AOCC. The "dragonegg.so" referenced here is the "AOCC Fortran Plugin".
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking. Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking. Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
Invoke the GNU Fortran compiler with the optimizers and code generators replaced by those from AOCC. The "dragonegg.so" referenced here is the "AOCC Fortran Plugin".
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking. Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
Invoke the GNU Fortran compiler with the optimizers and code generators replaced by those from AOCC. The "dragonegg.so" referenced here is the "AOCC Fortran Plugin".
clang++ C++ compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking. Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking. Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
Invoke the GNU Fortran compiler with the optimizers and code generators replaced by those from AOCC. The "dragonegg.so" referenced here is the "AOCC Fortran Plugin".
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 macro indicates that Fortran functions called from C should have their names lower-cased.
The binary datasets for some of the Fortran benchmarks in the SPEC CPU suites are stored in big-endian format. This option is necessary for those datasets to be read in correctly.
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.
Fortran to C symbol naming. C symbol names are lower case with one underscore. _symbol
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.
For netcdf, if defined uses Fortran symbol names ABC as abc_
The binary datasets for some of the Fortran benchmarks in the SPEC CPU suites are stored in big-endian format. This option is necessary for those datasets to be read in correctly.
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.
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 macro indicates that Fortran functions called from C should have their names lower-cased.
The binary datasets for some of the Fortran benchmarks in the SPEC CPU suites are stored in big-endian format. This option is necessary for those datasets to be read in correctly.
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.
Fortran to C symbol naming. C symbol names are lower case with one underscore. _symbol
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.
For netcdf, if defined uses Fortran symbol names ABC as abc_
The binary datasets for some of the Fortran benchmarks in the SPEC CPU suites are stored in big-endian format. This option is necessary for those datasets to be read in correctly.
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.
Generate output files in LLVM formats suitable for link time optimization. When used with -S this generates LLVM intermediate language assembly files, otherwise this generates LLVM bitcode format object files (which may be passed to the linker depending on the stage selection options).
This optimization merges duplicate constant uses into a register to reduce instruction width.
Enables loop strength reduction for nested loop structures. By default, the compiler will do loop strength reduction only for the innermost loop.
Certain loops with breaks may be vectorized by default at -O2 and above. In some extreme situations this may result in unsafe behavior. Use this option to disable vectorization of such loops.
Like -O2, except that it enables optimizations that take longer to perform or that may generate larger code (in an attempt to make the program run faster).
If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations that may not conform to the IEEE-754 specifications. When this option is specified, the __STDC_IEC_559__ macro is ignored even if set by the system headers.
Specify that Clang should generate code for a specific processor family member and later. For example, if you specify -march=znver1, the compiler is allowed to generate instructions that are valid on AMD Zen processors, but which may not exist on earlier products.
This option restricts the optimization and code generation to first-generation AVX instructions.
This option enables transformation of the layout of arrays of structure types and their fields to improve the cache locality. Aggressive analysis and transformations are performed at higher levels. This option is effective only with -flto as whole program analysis is required to perform this optimization.
Possible values:
Sets the limit at which loops will be unrolled. For example, if unroll threshold is set to 100 then only loops with 100 or fewer instructions will be unrolled.
This option enables an optimization that transforms the data layout of a single dimensional array to provide better cache locality by analyzing the access patterns.
Sets the compiler's inlining threshold level to the value passed. The inline threshold is used in the inliner heuristics to decide which functions should be inlined.
This option enables an optimization that generates and calls specialized function versions when the loops inside function are vectorizable and the arguments are not aliased with each other. This optimization helps in function inlining and vectorization.
This option enables the GVN hoist pass, which is used to hoist computations from branches.
This option enables an optimization that generates and calls specialized function versions when they are called with constant arguments. This optimization helps in function inlining.
Instructs the linker to use the first definition encountered for a symbol, and ignore all others.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
Enable handling of OpenMP directives and generate parallel code.
Switch to enable OpenMP.
Enable handling of OpenMP directives and generate parallel code.
Instructs the compiler to link with the OpenMP runtime libraries.
This option instructs the linker to link the executable with the pthread library.
This option instructs the linker to link the executable with libdl, the interface to the dynamic loader.
Use the jemalloc library, which is a general purpose malloc(3) implementation that emphasizes fragmentation avoidance and scalable concurrency support.
Instructs the compiler to link with AMD-supported optimized math library.
Generate output files in LLVM formats suitable for link time optimization. When used with -S this generates LLVM intermediate language assembly files, otherwise this generates LLVM bitcode format object files (which may be passed to the linker depending on the stage selection options).
This optimization merges duplicate constant uses into a register to reduce instruction width.
Enables loop strength reduction for nested loop structures. By default, the compiler will do loop strength reduction only for the innermost loop.
Certain loops with breaks may be vectorized by default at -O2 and above. In some extreme situations this may result in unsafe behavior. Use this option to disable vectorization of such loops.
Like -O2, except that it enables optimizations that take longer to perform or that may generate larger code (in an attempt to make the program run faster).
If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective.
Generate code for processors that include the AVX extensions.
This option enables generation of the adx instruction.
This option instructs the compiler to unroll loops wherever possible.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations that may not conform to the IEEE-754 specifications. When this option is specified, the __STDC_IEC_559__ macro is ignored even if set by the system headers.
Instructs the linker to use the first definition encountered for a symbol, and ignore all others.
Load compiler plugin code from the dragonegg.so file.
This optimization merges duplicate constant uses into a register to reduce instruction width.
Certain loops with breaks may be vectorized by default at -O2 and above. In some extreme situations this may result in unsafe behavior. Use this option to disable vectorization of such loops.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
Switch to enable OpenMP.
Enable handling of OpenMP directives and generate parallel code.
Enable handling of OpenMP directives and generate parallel code.
Instructs the compiler to link with the OpenMP runtime libraries.
This option instructs the linker to link the executable with the pthread library.
This option instructs the linker to link the executable with libdl, the interface to the dynamic loader.
Use the jemalloc library, which is a general purpose malloc(3) implementation that emphasizes fragmentation avoidance and scalable concurrency support.
Instructs the compiler to link with AMD-supported optimized math library.
Instructs the compiler to link with the gfortran Fortran runtime libraries.
Generate output files in LLVM formats suitable for link time optimization. When used with -S this generates LLVM intermediate language assembly files, otherwise this generates LLVM bitcode format object files (which may be passed to the linker depending on the stage selection options).
This optimization merges duplicate constant uses into a register to reduce instruction width.
Enables loop strength reduction for nested loop structures. By default, the compiler will do loop strength reduction only for the innermost loop.
Certain loops with breaks may be vectorized by default at -O2 and above. In some extreme situations this may result in unsafe behavior. Use this option to disable vectorization of such loops.
Like -O2, except that it enables optimizations that take longer to perform or that may generate larger code (in an attempt to make the program run faster).
If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations that may not conform to the IEEE-754 specifications. When this option is specified, the __STDC_IEC_559__ macro is ignored even if set by the system headers.
Specify that Clang should generate code for a specific processor family member and later. For example, if you specify -march=znver1, the compiler is allowed to generate instructions that are valid on AMD Zen processors, but which may not exist on earlier products.
This option restricts the optimization and code generation to first-generation AVX instructions.
This option enables transformation of the layout of arrays of structure types and their fields to improve the cache locality. Aggressive analysis and transformations are performed at higher levels. This option is effective only with -flto as whole program analysis is required to perform this optimization.
Possible values:
Sets the limit at which loops will be unrolled. For example, if unroll threshold is set to 100 then only loops with 100 or fewer instructions will be unrolled.
This option enables an optimization that transforms the data layout of a single dimensional array to provide better cache locality by analyzing the access patterns.
Sets the compiler's inlining threshold level to the value passed. The inline threshold is used in the inliner heuristics to decide which functions should be inlined.
This option enables an optimization that generates and calls specialized function versions when the loops inside function are vectorizable and the arguments are not aliased with each other. This optimization helps in function inlining and vectorization.
This option enables the GVN hoist pass, which is used to hoist computations from branches.
This option enables an optimization that generates and calls specialized function versions when they are called with constant arguments. This optimization helps in function inlining.
Generate code for processors that include the AVX extensions.
This option enables generation of the adx instruction.
This option instructs the compiler to unroll loops wherever possible.
Instructs the linker to use the first definition encountered for a symbol, and ignore all others.
Load compiler plugin code from the dragonegg.so file.
This optimization merges duplicate constant uses into a register to reduce instruction width.
Certain loops with breaks may be vectorized by default at -O2 and above. In some extreme situations this may result in unsafe behavior. Use this option to disable vectorization of such loops.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
Switch to enable OpenMP.
Enable handling of OpenMP directives and generate parallel code.
Enable handling of OpenMP directives and generate parallel code.
Instructs the compiler to link with the OpenMP runtime libraries.
This option instructs the linker to link the executable with the pthread library.
This option instructs the linker to link the executable with libdl, the interface to the dynamic loader.
Use the jemalloc library, which is a general purpose malloc(3) implementation that emphasizes fragmentation avoidance and scalable concurrency support.
Instructs the compiler to link with AMD-supported optimized math library.
Instructs the compiler to link with the gfortran Fortran runtime libraries.
Selects the C++ language dialect.
Generate output files in LLVM formats suitable for link time optimization. When used with -S this generates LLVM intermediate language assembly files, otherwise this generates LLVM bitcode format object files (which may be passed to the linker depending on the stage selection options).
This optimization merges duplicate constant uses into a register to reduce instruction width.
Enables loop strength reduction for nested loop structures. By default, the compiler will do loop strength reduction only for the innermost loop.
Certain loops with breaks may be vectorized by default at -O2 and above. In some extreme situations this may result in unsafe behavior. Use this option to disable vectorization of such loops.
Like -O2, except that it enables optimizations that take longer to perform or that may generate larger code (in an attempt to make the program run faster).
If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations that may not conform to the IEEE-754 specifications. When this option is specified, the __STDC_IEC_559__ macro is ignored even if set by the system headers.
Specify that Clang should generate code for a specific processor family member and later. For example, if you specify -march=znver1, the compiler is allowed to generate instructions that are valid on AMD Zen processors, but which may not exist on earlier products.
This option restricts the optimization and code generation to first-generation AVX instructions.
This option enables transformation of the layout of arrays of structure types and their fields to improve the cache locality. Aggressive analysis and transformations are performed at higher levels. This option is effective only with -flto as whole program analysis is required to perform this optimization.
Possible values:
Sets the limit at which loops will be unrolled. For example, if unroll threshold is set to 100 then only loops with 100 or fewer instructions will be unrolled.
This option enables an optimization that transforms the data layout of a single dimensional array to provide better cache locality by analyzing the access patterns.
Sets the compiler's inlining threshold level to the value passed. The inline threshold is used in the inliner heuristics to decide which functions should be inlined.
This option enables an optimization that generates and calls specialized function versions when the loops inside function are vectorizable and the arguments are not aliased with each other. This optimization helps in function inlining and vectorization.
This option enables the GVN hoist pass, which is used to hoist computations from branches.
This option enables an optimization that generates and calls specialized function versions when they are called with constant arguments. This optimization helps in function inlining.
Sets the limit at which loops will be unrolled. For example, if unroll threshold is set to 100 then only loops with 100 or fewer instructions will be unrolled.
Sets the compiler's inlining heuristics to an aggressive level by increasing the inline thresholds.
Certain loops with breaks may be vectorized by default at -O2 and above. In some extreme situations this may result in unsafe behavior. Use this option to disable vectorization of such loops.
Generate code for processors that include the AVX extensions.
This option enables generation of the adx instruction.
This option instructs the compiler to unroll loops wherever possible.
Instructs the linker to use the first definition encountered for a symbol, and ignore all others.
Load compiler plugin code from the dragonegg.so file.
This optimization merges duplicate constant uses into a register to reduce instruction width.
Certain loops with breaks may be vectorized by default at -O2 and above. In some extreme situations this may result in unsafe behavior. Use this option to disable vectorization of such loops.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
Enable handling of OpenMP directives and generate parallel code.
Switch to enable OpenMP.
Enable handling of OpenMP directives and generate parallel code.
Instructs the compiler to link with the OpenMP runtime libraries.
This option instructs the linker to link the executable with the pthread library.
This option instructs the linker to link the executable with libdl, the interface to the dynamic loader.
Use the jemalloc library, which is a general purpose malloc(3) implementation that emphasizes fragmentation avoidance and scalable concurrency support.
Instructs the compiler to link with AMD-supported optimized math library.
Selects the C++ language dialect.
Generate output files in LLVM formats suitable for link time optimization. When used with -S this generates LLVM intermediate language assembly files, otherwise this generates LLVM bitcode format object files (which may be passed to the linker depending on the stage selection options).
This optimization merges duplicate constant uses into a register to reduce instruction width.
Enables loop strength reduction for nested loop structures. By default, the compiler will do loop strength reduction only for the innermost loop.
Enables all the optimizations from -O3 along with other aggressive optimizations that may violate strict compliance with language standards. Refer to the AOCC options document for the language you're using for more detailed documentation of optimizations enabled under -Ofast.
Specify that Clang should generate code for a specific processor family member and later. For example, if you specify -march=znver1, the compiler is allowed to generate instructions that are valid on AMD Zen processors, but which may not exist on earlier products.
This option enables transformation of the layout of arrays of structure types and their fields to improve the cache locality. Aggressive analysis and transformations are performed at higher levels. This option is effective only with -flto as whole program analysis is required to perform this optimization.
Possible values:
This option avoids runtime memory dependency checks to enable aggressive vectorization.
This option restricts the optimization and code generation to first-generation AVX instructions.
Sets the limit at which loops will be unrolled. For example, if unroll threshold is set to 100 then only loops with 100 or fewer instructions will be unrolled.
This option enables an optimization that transforms the data layout of a single dimensional array to provide better cache locality by analyzing the access patterns.
Sets the compiler's inlining threshold level to the value passed. The inline threshold is used in the inliner heuristics to decide which functions should be inlined.
Sets the compiler's inlining heuristics to an aggressive level by increasing the inline thresholds.
Like -O2, except that it enables optimizations that take longer to perform or that may generate larger code (in an attempt to make the program run faster).
If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective.
This option enables AVX2 (Advanced Vector Extensions, 2nd generation) support.
This option enables generation of the adx instruction.
This option instructs the compiler to unroll loops wherever possible.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations that may not conform to the IEEE-754 specifications. When this option is specified, the __STDC_IEC_559__ macro is ignored even if set by the system headers.
Load compiler plugin code from the dragonegg.so file.
This optimization merges duplicate constant uses into a register to reduce instruction width.
Sets the compiler's inlining threshold level to the value passed. The inline threshold is used in the inliner heuristics to decide which functions should be inlined.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
Enable handling of OpenMP directives and generate parallel code.
Switch to enable OpenMP.
Enable handling of OpenMP directives and generate parallel code.
Instructs the compiler to link with the OpenMP runtime libraries.
This option instructs the linker to link the executable with the pthread library.
This option instructs the linker to link the executable with libdl, the interface to the dynamic loader.
Use the jemalloc library, which is a general purpose malloc(3) implementation that emphasizes fragmentation avoidance and scalable concurrency support.
Instructs the compiler to link with AMD-supported optimized math library.
Do not warn about functions defined with a return type that defaults to "int" or which return something other than what they were declared to.
Do not warn about functions defined with a return type that defaults to "int" or which return something other than what they were declared to.
Do not warn about functions defined with a return type that defaults to "int" or which return something other than what they were declared to.
Do not warn about functions defined with a return type that defaults to "int" or which return something other than what they were declared to.
Do not warn about functions defined with a return type that defaults to "int" or which return something other than what they were declared to.
Do not warn about functions defined with a return type that defaults to "int" or which return something other than what they were declared to.
Do not warn about functions defined with a return type that defaults to "int" or which return something other than what they were declared to.
Do not warn about functions defined with a return type that defaults to "int" or which return something other than what they were declared to.
This section contains descriptions of flags that were included implicitly by other flags, but which do not have a permanent home at SPEC.
Somewhere between -O0 and -O2.
If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective.
This result has been formatted using multiple flags files. The "submit command" from each of them appears next.
Using numactl
to bind processes and memory to cores
For multi-copy runs or single copy runs on systems with multiple sockets, it is advantageous to bind a process to a
particular core. Otherwise, the OS may arbitrarily move your process from one core to another. This can affect
performance. To help, SPEC allows the use of a "submit" command where users can specify a utility to use to bind
processes. We have found the utility 'numactl
' to be the best choice.
numactl
runs processes with a specific NUMA scheduling or memory placement policy. The policy is set for a
command and inherited by all of its children. The numactl
flag "--physcpubind
" specifies
which core(s) to bind the process. "-l
" instructs numactl
to keep a process's memory on the
local node while "-m
" specifies which node(s) to place a process's memory. For full details on using
numactl
, please refer to your Linux documentation, 'man numactl
'
Note that some older versions of numactl
incorrectly interpret application arguments as its own. For
example, with the command "numactl --physcpubind=0 -l a.out -m a
", numactl
will interpret
a.out
's "-m
" option as its own "-m
" option. To work around this problem, we put
the command to be run in a shell script and then run the shell script using numactl
. For example:
"echo 'a.out -m a' > run.sh ; numactl --physcpubind=0 bash run.sh
"
SPECrate runs might use one of these methods to bind processes to specific processors, depending on the config file.
Linux systems: the numactl command is commonly used. Here is a brief guide to understanding the specific command which will be found in the config file:
Solaris systems: The pbind command is commonly used, via
submit=echo 'pbind -b...' > dobmk; sh dobmk
The specific command may be found in the config file; here is a brief guide to understanding that command:
pbind -b causes this copy's processes to be bound to the CPU specified by the expression that follows it. See the config file used in the run for the exact syntax, which tends to be cumbersome because of the need to carefully quote parts of the expression. When all expressions are evaluated, the jobs are typically distributed evenly across the system, with each chip running the same number of jobs as all other chips, and each core running the same number of jobs as all other cores.
The pbind expression may include various elements from the SPEC toolset and from standard Unix commands, such as:
No special commands are needed for feedback-directed optimization, other than the compiler profile flags.
This result has been formatted using multiple flags files. The "sw environment" from each of them appears next.
Transparent Huge Pages (THP)
THP is an abstraction layer that automates most aspects of creating, managing, and using huge pages. THP is designed to hide much of the complexity in using huge pages from system administrators and developers, as normal huge pages must be assigned at boot time, can be difficult to manage manually, and often require significant changes to code in order to be used effectively. Most recent Linux OS releases have THP enabled by default.
Linux Huge Page settings
If you need finer control you can manually set huge pages using the following steps:
mkdir /mnt/hugepages
mount -t hugetlbfs nodev /mnt/hugepages
vm/nr_hugepages=N
in /etc/sysctl.conf
where N is the maximum number of pages the
system may allocate.Note that further information about huge pages may be found in the Linux kernel documentation file
hugetlbpage.txt
.
ulimit -s <n>
Sets the stack size to n kbytes, or unlimited to allow the stack size to grow without limit.
ulimit -l <n>
Sets the maximum size of memory that may be locked into physical memory.
cpupower frequency-set -r -g performance
(on Ubuntu, SLES, RHEL)
Sets the CPU governor to "performance" to enable the highest supported performance state for all cores.
powersave -f
(on SuSE)
Makes the powersave daemon set the CPUs to the highest supported frequency.
/etc/init.d/cpuspeed stop
(on Red Hat)
Disables the cpu frequency scaling program in order to set the CPUs to the highest supported frequency.
OMP_NUM_THREADS
Sets the maximum number of OpenMP parallel threads applications based on OpenMP may use.
LD_LIBRARY_PATH
An environment variable that indicates the location in the filesystem of bundled libraries to use when running the benchmark binaries.
kernel/randomize_va_space
This option can be used to select the type of process address space randomization that is used in the system, for architectures that support this feature.
norandmaps
" parameter.CONFIG_COMPAT_BRK
option is enabled.CONFIG_COMPAT_BRK
is
disabled.MALLOC_CONF
An environment variable set to tune the jemalloc allocation strategy during the execution of the binaries. This environment variable setting is not needed when building the binaries on the system under test.
One or more of the following may have been used in the run. If so, it will be listed in the notes sections. Here is a brief guide to understanding them:
LD_LIBRARY_PATH=<directories> (set via config file preENV)
LD_LIBRARY_PATH controls the search order for libraries. Often, it can be defaulted. Sometimes, it is
explicitly set (as documented in the notes in the submission), in order to ensure that the correct versions of
libraries are picked up.
OMP_STACKSIZE=N (set via config file preENV)
Set the stack size for subordinate threads.
ulimit -s N
ulimit -s unlimited
'ulimit' is a Unix commands, entered prior to the run. It sets the stack size for the main process, either
to N kbytes or to no limit.
Flag description origin markings:
For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact info@spec.org
Copyright 2017-2019 Standard Performance Evaluation Corporation
Tested with SPEC CPU2017 v1.0.5.
Report generated on 2019-10-15 14:40:19 by SPEC CPU2017 flags formatter v5178.