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 2006-2026 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.txt and on the web at https://www.spec.org/cpu2026/Docs/licenses/FDL.v1.3.txt. A copy of "Funding Free Software" is on your SPEC CPU kit at $SPEC/Docs/licenses/FundingFreeSW.txt and on the web at https://www.spec.org/cpu2026/Docs/licenses/FundingFreeSW.txt.
(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.
![[user]](https://www.spec.org/auto/cpu2026/images/user.png)
Invokes the GNU C compiler.
Invokes the GNU C++ compiler.
Invokes the GNU C++ compiler.
Invokes the GNU C compiler.
Invokes the GNU C compiler.
Invokes the GNU C++ compiler.
Invokes the GNU C++ compiler.
Invokes the GNU C compiler.
![[suite]](https://www.spec.org/auto/cpu2026/images/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.
Do not allow optimizations for floating-point arithmetic that assume that arguments and results are not NaNs or +-Infs.
A SPEC CPU config file might use this flag in combination with -Ofast, to specify that all the optimizations of -Ofast are desired, with the exception of -ffinite-math-only.
You may need to use this flag in order to get certain benchmarks to validate. If it is needed, the normal rules about portability flags apply.
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.
Do not allow optimizations for floating-point arithmetic that assume that arguments and results are not NaNs or +-Infs.
A SPEC CPU config file might use this flag in combination with -Ofast, to specify that all the optimizations of -Ofast are desired, with the exception of -ffinite-math-only.
You may need to use this flag in order to get certain benchmarks to validate. If it is needed, the normal rules about portability flags apply.
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.
Do not allow optimizations for floating-point arithmetic that assume that arguments and results are not NaNs or +-Infs.
A SPEC CPU config file might use this flag in combination with -Ofast, to specify that all the optimizations of -Ofast are desired, with the exception of -ffinite-math-only.
You may need to use this flag in order to get certain benchmarks to validate. If it is needed, the normal rules about portability flags apply.
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.
Do not allow optimizations for floating-point arithmetic that assume that arguments and results are not NaNs or +-Infs.
A SPEC CPU config file might use this flag in combination with -Ofast, to specify that all the optimizations of -Ofast are desired, with the exception of -ffinite-math-only.
You may need to use this flag in order to get certain benchmarks to validate. If it is needed, the normal rules about portability flags apply.
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.
Do not allow optimizations for floating-point arithmetic that assume that arguments and results are not NaNs or +-Infs.
A SPEC CPU config file might use this flag in combination with -Ofast, to specify that all the optimizations of -Ofast are desired, with the exception of -ffinite-math-only.
You may need to use this flag in order to get certain benchmarks to validate. If it is needed, the normal rules about portability flags apply.
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.
Do not allow optimizations for floating-point arithmetic that assume that arguments and results are not NaNs or +-Infs.
A SPEC CPU config file might use this flag in combination with -Ofast, to specify that all the optimizations of -Ofast are desired, with the exception of -ffinite-math-only.
You may need to use this flag in order to get certain benchmarks to validate. If it is needed, the normal rules about portability flags apply.
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 code for lp64. With ilp32, int, long int and pointer are 32-bit; with lp64, int is 32-bit, but long int and pointer are 64-bit.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Produce debugging information.
Increases optimization levels: the higher the number, the more optimization is done. Higher levels of optimization may
require additional compilation time, in the hopes of reducing execution time. At -O, basic optimizations are performed,
such as constant merging and elimination of dead code. At -O2, additional optimizations are added, such as common
subexpression elimination and strict aliasing. At -O3, even more optimizations are performed, such as function inlining and
vectorization.
Many more details are available.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations.
On aarch64 systems, -mcpu sets the kind of instructions that can be used (as if by -march) and how to tune for performance (as if by -mtune).
On x86 systems, -mcpu is a deprecated synonym for -mtune.
Enables link time optimization. When invoked with source code, it generates GIMPLE (one of GCC's internal representations) and writes it to special ELF sections in the object file. When the object files are linked together, all the function bodies are read from these ELF sections and instantiated as if they had been part of the same translation unit.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Link with libjemalloc, a fast, arena-based memory allocator.
Generate code for lp64. With ilp32, int, long int and pointer are 32-bit; with lp64, int is 32-bit, but long int and pointer are 64-bit.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Produce debugging information.
Increases optimization levels: the higher the number, the more optimization is done. Higher levels of optimization may
require additional compilation time, in the hopes of reducing execution time. At -O, basic optimizations are performed,
such as constant merging and elimination of dead code. At -O2, additional optimizations are added, such as common
subexpression elimination and strict aliasing. At -O3, even more optimizations are performed, such as function inlining and
vectorization.
Many more details are available.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations.
On aarch64 systems, -mcpu sets the kind of instructions that can be used (as if by -march) and how to tune for performance (as if by -mtune).
On x86 systems, -mcpu is a deprecated synonym for -mtune.
Enables link time optimization. When invoked with source code, it generates GIMPLE (one of GCC's internal representations) and writes it to special ELF sections in the object file. When the object files are linked together, all the function bodies are read from these ELF sections and instantiated as if they had been part of the same translation unit.
Enable support for POSIX Threads. Note that C++ programs using std::thread may require this flag.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Link with libjemalloc, a fast, arena-based memory allocator.
Generate code for lp64. With ilp32, int, long int and pointer are 32-bit; with lp64, int is 32-bit, but long int and pointer are 64-bit.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Produce debugging information.
Increases optimization levels: the higher the number, the more optimization is done. Higher levels of optimization may
require additional compilation time, in the hopes of reducing execution time. At -O, basic optimizations are performed,
such as constant merging and elimination of dead code. At -O2, additional optimizations are added, such as common
subexpression elimination and strict aliasing. At -O3, even more optimizations are performed, such as function inlining and
vectorization.
Many more details are available.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations.
On aarch64 systems, -mcpu sets the kind of instructions that can be used (as if by -march) and how to tune for performance (as if by -mtune).
On x86 systems, -mcpu is a deprecated synonym for -mtune.
Enables link time optimization. When invoked with source code, it generates GIMPLE (one of GCC's internal representations) and writes it to special ELF sections in the object file. When the object files are linked together, all the function bodies are read from these ELF sections and instantiated as if they had been part of the same translation unit.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Link with libjemalloc, a fast, arena-based memory allocator.
Generate code for lp64. With ilp32, int, long int and pointer are 32-bit; with lp64, int is 32-bit, but long int and pointer are 64-bit.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Produce debugging information.
Increases optimization levels: the higher the number, the more optimization is done. Higher levels of optimization may
require additional compilation time, in the hopes of reducing execution time. At -O, basic optimizations are performed,
such as constant merging and elimination of dead code. At -O2, additional optimizations are added, such as common
subexpression elimination and strict aliasing. At -O3, even more optimizations are performed, such as function inlining and
vectorization.
Many more details are available.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations.
On aarch64 systems, -mcpu sets the kind of instructions that can be used (as if by -march) and how to tune for performance (as if by -mtune).
On x86 systems, -mcpu is a deprecated synonym for -mtune.
Enables link time optimization. When invoked with source code, it generates GIMPLE (one of GCC's internal representations) and writes it to special ELF sections in the object file. When the object files are linked together, all the function bodies are read from these ELF sections and instantiated as if they had been part of the same translation unit.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Link with libjemalloc, a fast, arena-based memory allocator.
Generate code for lp64. With ilp32, int, long int and pointer are 32-bit; with lp64, int is 32-bit, but long int and pointer are 64-bit.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Produce debugging information.
Increases optimization levels: the higher the number, the more optimization is done. Higher levels of optimization may
require additional compilation time, in the hopes of reducing execution time. At -O, basic optimizations are performed,
such as constant merging and elimination of dead code. At -O2, additional optimizations are added, such as common
subexpression elimination and strict aliasing. At -O3, even more optimizations are performed, such as function inlining and
vectorization.
Many more details are available.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations.
On aarch64 systems, -mcpu sets the kind of instructions that can be used (as if by -march) and how to tune for performance (as if by -mtune).
On x86 systems, -mcpu is a deprecated synonym for -mtune.
Enables link time optimization. When invoked with source code, it generates GIMPLE (one of GCC's internal representations) and writes it to special ELF sections in the object file. When the object files are linked together, all the function bodies are read from these ELF sections and instantiated as if they had been part of the same translation unit.
Enable support for POSIX Threads. Note that C++ programs using std::thread may require this flag.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Link with libjemalloc, a fast, arena-based memory allocator.
Generate code for lp64. With ilp32, int, long int and pointer are 32-bit; with lp64, int is 32-bit, but long int and pointer are 64-bit.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Instruments code to collect information for profile-driven feedback. Information is collected regarding both code paths and data values.
Applies information from a profile run in order to improve optimization. Several optimizations are improved when profile data is available, including branch probabilities, loop peeling, and loop unrolling.
Produce debugging information.
Disregard strict standards compliance. -Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs. It turns on -ffast-math, -fallow-store-data-races (as of GCC 10), and the Fortran-specific -fstack-arrays unless -fmax-stack-var-size is specified, and -fno-protect-parens.
On aarch64 systems, -mcpu sets the kind of instructions that can be used (as if by -march) and how to tune for performance (as if by -mtune).
On x86 systems, -mcpu is a deprecated synonym for -mtune.
Enables link time optimization. When invoked with source code, it generates GIMPLE (one of GCC's internal representations) and writes it to special ELF sections in the object file. When the object files are linked together, all the function bodies are read from these ELF sections and instantiated as if they had been part of the same translation unit.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Link with libjemalloc, a fast, arena-based memory allocator.
Generate code for lp64. With ilp32, int, long int and pointer are 32-bit; with lp64, int is 32-bit, but long int and pointer are 64-bit.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Instruments code to collect information for profile-driven feedback. Information is collected regarding both code paths and data values.
Applies information from a profile run in order to improve optimization. Several optimizations are improved when profile data is available, including branch probabilities, loop peeling, and loop unrolling.
Produce debugging information.
Disregard strict standards compliance. -Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs. It turns on -ffast-math, -fallow-store-data-races (as of GCC 10), and the Fortran-specific -fstack-arrays unless -fmax-stack-var-size is specified, and -fno-protect-parens.
On aarch64 systems, -mcpu sets the kind of instructions that can be used (as if by -march) and how to tune for performance (as if by -mtune).
On x86 systems, -mcpu is a deprecated synonym for -mtune.
Enables link time optimization. When invoked with source code, it generates GIMPLE (one of GCC's internal representations) and writes it to special ELF sections in the object file. When the object files are linked together, all the function bodies are read from these ELF sections and instantiated as if they had been part of the same translation unit.
Enable support for POSIX Threads. Note that C++ programs using std::thread may require this flag.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Link with libjemalloc, a fast, arena-based memory allocator.
Generate code for lp64. With ilp32, int, long int and pointer are 32-bit; with lp64, int is 32-bit, but long int and pointer are 64-bit.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Instruments code to collect information for profile-driven feedback. Information is collected regarding both code paths and data values.
Applies information from a profile run in order to improve optimization. Several optimizations are improved when profile data is available, including branch probabilities, loop peeling, and loop unrolling.
Produce debugging information.
Disregard strict standards compliance. -Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs. It turns on -ffast-math, -fallow-store-data-races (as of GCC 10), and the Fortran-specific -fstack-arrays unless -fmax-stack-var-size is specified, and -fno-protect-parens.
On aarch64 systems, -mcpu sets the kind of instructions that can be used (as if by -march) and how to tune for performance (as if by -mtune).
On x86 systems, -mcpu is a deprecated synonym for -mtune.
Enables link time optimization. When invoked with source code, it generates GIMPLE (one of GCC's internal representations) and writes it to special ELF sections in the object file. When the object files are linked together, all the function bodies are read from these ELF sections and instantiated as if they had been part of the same translation unit.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Link with libjemalloc, a fast, arena-based memory allocator.
Generate code for lp64. With ilp32, int, long int and pointer are 32-bit; with lp64, int is 32-bit, but long int and pointer are 64-bit.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Instruments code to collect information for profile-driven feedback. Information is collected regarding both code paths and data values.
Applies information from a profile run in order to improve optimization. Several optimizations are improved when profile data is available, including branch probabilities, loop peeling, and loop unrolling.
Produce debugging information.
Disregard strict standards compliance. -Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs. It turns on -ffast-math, -fallow-store-data-races (as of GCC 10), and the Fortran-specific -fstack-arrays unless -fmax-stack-var-size is specified, and -fno-protect-parens.
On aarch64 systems, -mcpu sets the kind of instructions that can be used (as if by -march) and how to tune for performance (as if by -mtune).
On x86 systems, -mcpu is a deprecated synonym for -mtune.
Enables link time optimization. When invoked with source code, it generates GIMPLE (one of GCC's internal representations) and writes it to special ELF sections in the object file. When the object files are linked together, all the function bodies are read from these ELF sections and instantiated as if they had been part of the same translation unit.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Link with libjemalloc, a fast, arena-based memory allocator.
Generate code for lp64. With ilp32, int, long int and pointer are 32-bit; with lp64, int is 32-bit, but long int and pointer are 64-bit.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Sets the language standard to the specified version, for example c18, c++17, f2008.
Instruments code to collect information for profile-driven feedback. Information is collected regarding both code paths and data values.
Applies information from a profile run in order to improve optimization. Several optimizations are improved when profile data is available, including branch probabilities, loop peeling, and loop unrolling.
Produce debugging information.
Disregard strict standards compliance. -Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs. It turns on -ffast-math, -fallow-store-data-races (as of GCC 10), and the Fortran-specific -fstack-arrays unless -fmax-stack-var-size is specified, and -fno-protect-parens.
On aarch64 systems, -mcpu sets the kind of instructions that can be used (as if by -march) and how to tune for performance (as if by -mtune).
On x86 systems, -mcpu is a deprecated synonym for -mtune.
Enables link time optimization. When invoked with source code, it generates GIMPLE (one of GCC's internal representations) and writes it to special ELF sections in the object file. When the object files are linked together, all the function bodies are read from these ELF sections and instantiated as if they had been part of the same translation unit.
Enable support for POSIX Threads. Note that C++ programs using std::thread may require this flag.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Link with libjemalloc, a fast, arena-based memory allocator.
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:
macOS systems: processes are not bound.
No special commands are needed for feedback-directed optimization, other than the compiler profile flags.
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 OpenMP threads.
ulimit -s N
ulimit -s unlimited
'ulimit' is a Unix command, entered prior to the run. It sets the stack size for the main process and its children,
either to N kbytes or to no limit.
MALLOC_CONF=thp:always,metadata_thp:always (set via config file preENV)
MALLOC_CONF controls jemalloc behavior.
The "thp" option controls whether heap allocations jemalloc does use transparent huge pages, if THP is supported by the operating system. The "always" setting enables transparent hugepage for all user memory mappings with MADV_HUGEPAGE; "never" ensures no transparent hugepage with MADV_NOHUGEPAGE; the default setting "default" makes no changes.
The "metadata_thp" option controls whether to allow jemalloc to use transparent huge pages (THP) for internal metadata. The "always" setting allows such usage. The "auto" setting uses no THP initially, but may begin to do so when metadata usage reaches certain level. The default is "disabled".
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. |
![[benchmark]](https://www.spec.org/auto/cpu2026/images/benchmark.png) |
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 info@spec.org
Copyright 2026 Standard Performance Evaluation Corporation
Tested with SPEC CPU®2026 v0.903.0.
Report generated on 2026-05-04 23:26:37 by SPEC CPU®2026 flags formatter (5b352a85).