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, C++, and Objective-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.
The clang executable is actually a small driver which controls the overall execution of other tools such as the compiler, assembler and linker. Typically you do not need to interact with the driver, but you transparently use it to run the other tools.
PreprocessingThis stage handles tokenization of the input source file, macro expansion, #include expansion and handling of other preprocessor directives. The output of this stage is typically called a .i (for C), .ii (for C++), .mi (for Objective-C), or .mii (for Objective-C++) file.
This stage parses the input file, translating preprocessor tokens into a parse tree. Once in the form of a parse tree, it applies semantic analysis to compute types for expressions as well and determine whether the code is well formed. This stage is responsible for generating most of the compiler warnings as well as parse errors. The output of this stage is an Abstract Syntax Tree (AST).
Code Generation and OptimizationThis stage translates an AST into low-level intermediate code (known as LLVM IR) and ultimately to machine code. This phase is responsible for optimizing the generated code and handling target-specific code generation. The output of this stage is typically called a .s file or assembly file.
Clang also supports the use of an integrated assembler, in which the code generator produces object files directly. This avoids the overhead of generating the .s file and of calling the target assembler.
AssemblerThis stage runs the target assembler to translate the output of the compiler into a target object file. The output of this stage is typically called a .o file or object file.
LinkerThis stage runs the target linker to merge multiple object files into an executable or dynamic library. The output of this stage is typically called an a.out, .dylib or .so file.
clang is a C, C++, and Objective-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.
The clang executable is actually a small driver which controls the overall execution of other tools such as the compiler, assembler and linker. Typically you do not need to interact with the driver, but you transparently use it to run the other tools.
PreprocessingThis stage handles tokenization of the input source file, macro expansion, #include expansion and handling of other preprocessor directives. The output of this stage is typically called a .i (for C), .ii (for C++), .mi (for Objective-C), or .mii (for Objective-C++) file.
This stage parses the input file, translating preprocessor tokens into a parse tree. Once in the form of a parse tree, it applies semantic analysis to compute types for expressions as well and determine whether the code is well formed. This stage is responsible for generating most of the compiler warnings as well as parse errors. The output of this stage is an Abstract Syntax Tree (AST).
Code Generation and OptimizationThis stage translates an AST into low-level intermediate code (known as LLVM IR) and ultimately to machine code. This phase is responsible for optimizing the generated code and handling target-specific code generation. The output of this stage is typically called a .s file or assembly file.
Clang also supports the use of an integrated assembler, in which the code generator produces object files directly. This avoids the overhead of generating the .s file and of calling the target assembler.
AssemblerThis stage runs the target assembler to translate the output of the compiler into a target object file. The output of this stage is typically called a .o file or object file.
LinkerThis stage runs the target linker to merge multiple object files into an executable or dynamic library. The output of this stage is typically called an a.out, .dylib or .so file.
clang is a C, C++, and Objective-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.
The clang executable is actually a small driver which controls the overall execution of other tools such as the compiler, assembler and linker. Typically you do not need to interact with the driver, but you transparently use it to run the other tools.
PreprocessingThis stage handles tokenization of the input source file, macro expansion, #include expansion and handling of other preprocessor directives. The output of this stage is typically called a .i (for C), .ii (for C++), .mi (for Objective-C), or .mii (for Objective-C++) file.
This stage parses the input file, translating preprocessor tokens into a parse tree. Once in the form of a parse tree, it applies semantic analysis to compute types for expressions as well and determine whether the code is well formed. This stage is responsible for generating most of the compiler warnings as well as parse errors. The output of this stage is an Abstract Syntax Tree (AST).
Code Generation and OptimizationThis stage translates an AST into low-level intermediate code (known as LLVM IR) and ultimately to machine code. This phase is responsible for optimizing the generated code and handling target-specific code generation. The output of this stage is typically called a .s file or assembly file.
Clang also supports the use of an integrated assembler, in which the code generator produces object files directly. This avoids the overhead of generating the .s file and of calling the target assembler.
AssemblerThis stage runs the target assembler to translate the output of the compiler into a target object file. The output of this stage is typically called a .o file or object file.
LinkerThis stage runs the target linker to merge multiple object files into an executable or dynamic library. The output of this stage is typically called an a.out, .dylib or .so file.
Invokes the GNU Fortran compiler.
clang is a C, C++, and Objective-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.
The clang executable is actually a small driver which controls the overall execution of other tools such as the compiler, assembler and linker. Typically you do not need to interact with the driver, but you transparently use it to run the other tools.
PreprocessingThis stage handles tokenization of the input source file, macro expansion, #include expansion and handling of other preprocessor directives. The output of this stage is typically called a .i (for C), .ii (for C++), .mi (for Objective-C), or .mii (for Objective-C++) file.
This stage parses the input file, translating preprocessor tokens into a parse tree. Once in the form of a parse tree, it applies semantic analysis to compute types for expressions as well and determine whether the code is well formed. This stage is responsible for generating most of the compiler warnings as well as parse errors. The output of this stage is an Abstract Syntax Tree (AST).
Code Generation and OptimizationThis stage translates an AST into low-level intermediate code (known as LLVM IR) and ultimately to machine code. This phase is responsible for optimizing the generated code and handling target-specific code generation. The output of this stage is typically called a .s file or assembly file.
Clang also supports the use of an integrated assembler, in which the code generator produces object files directly. This avoids the overhead of generating the .s file and of calling the target assembler.
AssemblerThis stage runs the target assembler to translate the output of the compiler into a target object file. The output of this stage is typically called a .o file or object file.
LinkerThis stage runs the target linker to merge multiple object files into an executable or dynamic library. The output of this stage is typically called an a.out, .dylib or .so file.
clang is a C, C++, and Objective-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.
The clang executable is actually a small driver which controls the overall execution of other tools such as the compiler, assembler and linker. Typically you do not need to interact with the driver, but you transparently use it to run the other tools.
PreprocessingThis stage handles tokenization of the input source file, macro expansion, #include expansion and handling of other preprocessor directives. The output of this stage is typically called a .i (for C), .ii (for C++), .mi (for Objective-C), or .mii (for Objective-C++) file.
This stage parses the input file, translating preprocessor tokens into a parse tree. Once in the form of a parse tree, it applies semantic analysis to compute types for expressions as well and determine whether the code is well formed. This stage is responsible for generating most of the compiler warnings as well as parse errors. The output of this stage is an Abstract Syntax Tree (AST).
Code Generation and OptimizationThis stage translates an AST into low-level intermediate code (known as LLVM IR) and ultimately to machine code. This phase is responsible for optimizing the generated code and handling target-specific code generation. The output of this stage is typically called a .s file or assembly file.
Clang also supports the use of an integrated assembler, in which the code generator produces object files directly. This avoids the overhead of generating the .s file and of calling the target assembler.
AssemblerThis stage runs the target assembler to translate the output of the compiler into a target object file. The output of this stage is typically called a .o file or object file.
LinkerThis stage runs the target linker to merge multiple object files into an executable or dynamic library. The output of this stage is typically called an a.out, .dylib or .so file.
clang is a C, C++, and Objective-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.
The clang executable is actually a small driver which controls the overall execution of other tools such as the compiler, assembler and linker. Typically you do not need to interact with the driver, but you transparently use it to run the other tools.
PreprocessingThis stage handles tokenization of the input source file, macro expansion, #include expansion and handling of other preprocessor directives. The output of this stage is typically called a .i (for C), .ii (for C++), .mi (for Objective-C), or .mii (for Objective-C++) file.
This stage parses the input file, translating preprocessor tokens into a parse tree. Once in the form of a parse tree, it applies semantic analysis to compute types for expressions as well and determine whether the code is well formed. This stage is responsible for generating most of the compiler warnings as well as parse errors. The output of this stage is an Abstract Syntax Tree (AST).
Code Generation and OptimizationThis stage translates an AST into low-level intermediate code (known as LLVM IR) and ultimately to machine code. This phase is responsible for optimizing the generated code and handling target-specific code generation. The output of this stage is typically called a .s file or assembly file.
Clang also supports the use of an integrated assembler, in which the code generator produces object files directly. This avoids the overhead of generating the .s file and of calling the target assembler.
AssemblerThis stage runs the target assembler to translate the output of the compiler into a target object file. The output of this stage is typically called a .o file or object file.
LinkerThis stage runs the target linker to merge multiple object files into an executable or dynamic library. The output of this stage is typically called an a.out, .dylib or .so file.
Invokes the GNU Fortran compiler.
This macro indicates that the benchmark is being compiled on an AMD64-compatible system running the Linux operating system.
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 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 flag can be set for SPEC compilation for LINUX using default compiler.
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 the benchmark is being compiled on an AMD64-compatible system running the Linux operating system.
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.
Ensure that there are no surprises if the benchmarks are run in an environment where file system metadata uses 64 bits.
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 flag can be set for SPEC compilation for LINUX using default compiler.
Ensure that there are no surprises if the benchmarks are run in an environment where file system metadata uses 64 bits.
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).
Note:
-flto requires llvm to be build with gold-linker. The default binary releases of llvm from llvm.org do not have LLVMGold.so and so will not support -flto. To use -flto, you will have to
Download, configure and build binutils for gold with plugin support.
*** $ git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
*** $ mkdir build
*** $ cd build
*** $ ../binutils/configure --enable-gold --enable-plugins --disable-werror
*** $ make all-gold
That should leave you with build/gold/ld-new which supports the -plugin option. Running make will additionally build build/binutils/ar and nm-new binaries supporting plugins.
Build the LLVMgold plugin. Run CMake with -DLLVM_BINUTILS_INCDIR=/path/to/binutils/include. The correct include path will contain the file plugin-api.h.
Replace the existing binutils tools in /usr/bin with the newly built gold enabled binutils tools like ld, nm, ar. It is recommended that you use soft links to back up and replace existing ld, nm, ar with the gold enabled version.
-Wl tells the linker to accept the following argument. In the example, it tells the linker to allow multiple definitions.
-plugin-opt= tells the linker to pass the following argument to the plugin.
The 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 maybe 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. Level 2 is assumed if no value is specified (i.e. "-O". The default is "-O2".
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations.
On x86 systems, allows use of instructions that require the listed architecture.
This option transforms the layout of arrays of structure types and its fields to improve the cache locality. Possible values that can be specified are 1,2 and 3 Aggressive analysis and transformations are performed at higher level of transformations, with -fstruct-layout=3 being the most aggressive. Use -fstruct-layout=3 when you know the allocated size of array of structures fits within 64KB. Use the value of 2 when a similar size exceeds 64KB but does not exceed 4GB. The option is effective only under flto as the whole program analysis is required to perform this optimization.
Passes the option-name through the compiler frontend to the optimizer.
Sets the limit at which loops will be unrolled. For example,if unroll-threshold is set to 100 then only loops with 100 or less instructions will be unrolled.
The optimization transforms the data layout of a single dimensional array to provide better cache locality by analysing the access patterns.
Restricts the optimization and code generation to first-generation AVX instructions.
Sets the compiler's inlining threshold level to the value passed as argument. The inline threshold is used in the inliner heuristics to decide which function should be inlined
Allows links to proceed even if there are multiple definitions of some symbols. This switch may resolve duplicate symbol errors, as noted in the 502.gcc_r benchmark description.
Use the jemalloc library, which is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support.
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).
Note:
-flto requires llvm to be build with gold-linker. The default binary releases of llvm from llvm.org do not have LLVMGold.so and so will not support -flto. To use -flto, you will have to
Download, configure and build binutils for gold with plugin support.
*** $ git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
*** $ mkdir build
*** $ cd build
*** $ ../binutils/configure --enable-gold --enable-plugins --disable-werror
*** $ make all-gold
That should leave you with build/gold/ld-new which supports the -plugin option. Running make will additionally build build/binutils/ar and nm-new binaries supporting plugins.
Build the LLVMgold plugin. Run CMake with -DLLVM_BINUTILS_INCDIR=/path/to/binutils/include. The correct include path will contain the file plugin-api.h.
Replace the existing binutils tools in /usr/bin with the newly built gold enabled binutils tools like ld, nm, ar. It is recommended that you use soft links to back up and replace existing ld, nm, ar with the gold enabled version.
-Wl tells the linker to accept the following argument. In the example, it tells the linker to allow multiple definitions.
-plugin-opt= tells the linker to pass the following argument to the plugin.
The 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 maybe 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. Level 2 is assumed if no value is specified (i.e. "-O". The default is "-O2".
On x86 systems, allows use of instructions that require the listed architecture.
Passes the option-name through the compiler frontend to the optimizer.
Sets the limit at which loops will be unrolled. For example,if unroll-threshold is set to 100 then only loops with 100 or less instructions will be unrolled.
Sets the compiler's inlining heuristics to an aggressive level by increasing the inline thresholds.
The optimization transforms the data layout of a single dimensional array to provide better cache locality by analysing the access patterns.
Sets the compiler's inlining threshold level to the value passed as argument. The inline threshold is used in the inliner heuristics to decide which function should be inlined
Allows links to proceed even if there are multiple definitions of some symbols. This switch may resolve duplicate symbol errors, as noted in the 502.gcc_r benchmark description.
Use the jemalloc library, which is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support.
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).
Note:
-flto requires llvm to be build with gold-linker. The default binary releases of llvm from llvm.org do not have LLVMGold.so and so will not support -flto. To use -flto, you will have to
Download, configure and build binutils for gold with plugin support.
*** $ git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
*** $ mkdir build
*** $ cd build
*** $ ../binutils/configure --enable-gold --enable-plugins --disable-werror
*** $ make all-gold
That should leave you with build/gold/ld-new which supports the -plugin option. Running make will additionally build build/binutils/ar and nm-new binaries supporting plugins.
Build the LLVMgold plugin. Run CMake with -DLLVM_BINUTILS_INCDIR=/path/to/binutils/include. The correct include path will contain the file plugin-api.h.
Replace the existing binutils tools in /usr/bin with the newly built gold enabled binutils tools like ld, nm, ar. It is recommended that you use soft links to back up and replace existing ld, nm, ar with the gold enabled version.
-Wl tells the linker to accept the following argument. In the example, it tells the linker to allow multiple definitions.
-plugin-opt= tells the linker to pass the following argument to the plugin.
The 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 maybe 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
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.
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. Level 2 is assumed if no value is specified (i.e. "-O". The default is "-O2".
Generate code for processors that include the AVX extensions.
Enables the adcx instruction generation support.
Tells the optimizer to unroll loops whose number of iterations can be determined at compile time or upon entry to the loop.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations.
Allows links to proceed even if there are multiple definitions of some symbols. This switch may resolve duplicate symbol errors, as noted in the 502.gcc_r benchmark description.
Enable all optimizations of -O3 plus optimizations that are not valid for standard-compliant programs, such as re-ordering
operations without regard to parentheses.
Many more details are available.
Set the default integer and logical types to an 8 byte type. It does not promote variables with explicit KIND declaration.
Load the plugin code in file dragonegg.so, assumed to be a shared object to be dlopen'd by the compiler. In AOCC, DragonEgg is called the "AOCC Fortran Plugin".
Passes the argument list following the flag to the DragonEgg gfortran plugin. Each argument must be enclosed in quotes.
Enables splitting of long live ranges of loop induction variables which span loop boundaries. This helps reduce register pressure and can help avoid needless spills to memory and reloads from memory.
Sets the compiler's inlining threshold level to the value passed as argument. The inline threshold is used in the inliner heuristics to decide which function should be inlined. Use the option -fplugin-arg-dragonegg-llvm-option="-inline-threshold:1000" to pass this option to LLVM backend through dragonegg
Certain loops with breaks maybe 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. Use the option -fplugin-arg-dragonegg-llvm-option="-disable-vect-cmp" to pass this option to LLVM backend through dragonegg.
Use the jemalloc library, which is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support.
Instructs the compiler to link with gfortran libraries
Instructs the compiler to link with AMD-supported 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).
Note:
-flto requires llvm to be build with gold-linker. The default binary releases of llvm from llvm.org do not have LLVMGold.so and so will not support -flto. To use -flto, you will have to
Download, configure and build binutils for gold with plugin support.
*** $ git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
*** $ mkdir build
*** $ cd build
*** $ ../binutils/configure --enable-gold --enable-plugins --disable-werror
*** $ make all-gold
That should leave you with build/gold/ld-new which supports the -plugin option. Running make will additionally build build/binutils/ar and nm-new binaries supporting plugins.
Build the LLVMgold plugin. Run CMake with -DLLVM_BINUTILS_INCDIR=/path/to/binutils/include. The correct include path will contain the file plugin-api.h.
Replace the existing binutils tools in /usr/bin with the newly built gold enabled binutils tools like ld, nm, ar. It is recommended that you use soft links to back up and replace existing ld, nm, ar with the gold enabled version.
-Wl tells the linker to accept the following argument. In the example, it tells the linker to allow multiple definitions.
-plugin-opt= tells the linker to pass the following argument to the plugin.
The 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
Turns on LLVM's (and Clang's) instrumenation based profiling.
Uses the profiling files generated from a program compiled with -fprofile-instr-generate.
Enable all optimizations of -O3 plus optimizations that are not valid for standard-compliant programs, such as re-ordering
operations without regard to parentheses.
Many more details are available.
On x86 systems, allows use of instructions that require the listed architecture.
This option transforms the layout of arrays of structure types and its fields to improve the cache locality. Possible values that can be specified are 1,2 and 3 Aggressive analysis and transformations are performed at higher level of transformations, with -fstruct-layout=3 being the most aggressive. Use -fstruct-layout=3 when you know the allocated size of array of structures fits within 64KB. Use the value of 2 when a similar size exceeds 64KB but does not exceed 4GB. The option is effective only under flto as the whole program analysis is required to perform this optimization.
Passes the option-name through the compiler frontend to the optimizer.
This option avoids runtime memory dependency checks to enable aggressive vectorization.
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 less instructions will be unrolled.
The optimization transforms the data layout of a single dimensional array to provide better cache locality by analysing the access patterns.
Sets the compiler's inlining threshold level to the value passed as argument. The inline threshold is used in the inliner heuristics to decide which function should be inlined
Use the jemalloc library, which is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support.
Generate code for a 32-bit environment. The 32-bit environment sets int, long and pointer to 32 bits and generates code that runs on any i386 system. The compiler generates x86 or IA32 32-bit ABI. The default on a 32-bit host is 32-bit ABI. The default on a 64-bit host is 64-bit ABI if the target platform specified is 64-bit, otherwise the default is 32-bit.
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).
Note:
-flto requires llvm to be build with gold-linker. The default binary releases of llvm from llvm.org do not have LLVMGold.so and so will not support -flto. To use -flto, you will have to
Download, configure and build binutils for gold with plugin support.
*** $ git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
*** $ mkdir build
*** $ cd build
*** $ ../binutils/configure --enable-gold --enable-plugins --disable-werror
*** $ make all-gold
That should leave you with build/gold/ld-new which supports the -plugin option. Running make will additionally build build/binutils/ar and nm-new binaries supporting plugins.
Build the LLVMgold plugin. Run CMake with -DLLVM_BINUTILS_INCDIR=/path/to/binutils/include. The correct include path will contain the file plugin-api.h.
Replace the existing binutils tools in /usr/bin with the newly built gold enabled binutils tools like ld, nm, ar. It is recommended that you use soft links to back up and replace existing ld, nm, ar with the gold enabled version.
-Wl tells the linker to accept the following argument. In the example, it tells the linker to allow multiple definitions.
-plugin-opt= tells the linker to pass the following argument to the plugin.
The 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
Enable all optimizations of -O3 plus optimizations that are not valid for standard-compliant programs, such as re-ordering
operations without regard to parentheses.
Many more details are available.
On x86 systems, allows use of instructions that require the listed architecture.
This option transforms the layout of arrays of structure types and its fields to improve the cache locality. Possible values that can be specified are 1,2 and 3 Aggressive analysis and transformations are performed at higher level of transformations, with -fstruct-layout=3 being the most aggressive. Use -fstruct-layout=3 when you know the allocated size of array of structures fits within 64KB. Use the value of 2 when a similar size exceeds 64KB but does not exceed 4GB. The option is effective only under flto as the whole program analysis is required to perform this optimization.
Passes the option-name through the compiler frontend to the optimizer.
This option avoids runtime memory dependency checks to enable aggressive vectorization.
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 less instructions will be unrolled.
The optimization transforms the data layout of a single dimensional array to provide better cache locality by analysing the access patterns.
Sets the compiler's inlining threshold level to the value passed as argument. The inline threshold is used in the inliner heuristics to decide which function should be inlined
Tells GCC to use the GNU semantics for "inline" functions, that is, the behavior prior to the C99 standard. This switch may resolve duplicate symbol errors, as noted in the 502.gcc_r benchmark description.
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Use the jemalloc library, which is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support.
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).
Note:
-flto requires llvm to be build with gold-linker. The default binary releases of llvm from llvm.org do not have LLVMGold.so and so will not support -flto. To use -flto, you will have to
Download, configure and build binutils for gold with plugin support.
*** $ git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
*** $ mkdir build
*** $ cd build
*** $ ../binutils/configure --enable-gold --enable-plugins --disable-werror
*** $ make all-gold
That should leave you with build/gold/ld-new which supports the -plugin option. Running make will additionally build build/binutils/ar and nm-new binaries supporting plugins.
Build the LLVMgold plugin. Run CMake with -DLLVM_BINUTILS_INCDIR=/path/to/binutils/include. The correct include path will contain the file plugin-api.h.
Replace the existing binutils tools in /usr/bin with the newly built gold enabled binutils tools like ld, nm, ar. It is recommended that you use soft links to back up and replace existing ld, nm, ar with the gold enabled version.
-Wl tells the linker to accept the following argument. In the example, it tells the linker to allow multiple definitions.
-plugin-opt= tells the linker to pass the following argument to the plugin.
The 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
Enable all optimizations of -O3 plus optimizations that are not valid for standard-compliant programs, such as re-ordering
operations without regard to parentheses.
Many more details are available.
On x86 systems, allows use of instructions that require the listed architecture.
This option transforms the layout of arrays of structure types and its fields to improve the cache locality. Possible values that can be specified are 1,2 and 3 Aggressive analysis and transformations are performed at higher level of transformations, with -fstruct-layout=3 being the most aggressive. Use -fstruct-layout=3 when you know the allocated size of array of structures fits within 64KB. Use the value of 2 when a similar size exceeds 64KB but does not exceed 4GB. The option is effective only under flto as the whole program analysis is required to perform this optimization.
Passes the option-name through the compiler frontend to the optimizer.
This option avoids runtime memory dependency checks to enable aggressive vectorization.
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 less instructions will be unrolled.
The optimization transforms the data layout of a single dimensional array to provide better cache locality by analysing the access patterns.
Sets the compiler's inlining threshold level to the value passed as argument. The inline threshold is used in the inliner heuristics to decide which function should be inlined
Use the jemalloc library, which is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support.
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).
Note:
-flto requires llvm to be build with gold-linker. The default binary releases of llvm from llvm.org do not have LLVMGold.so and so will not support -flto. To use -flto, you will have to
Download, configure and build binutils for gold with plugin support.
*** $ git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
*** $ mkdir build
*** $ cd build
*** $ ../binutils/configure --enable-gold --enable-plugins --disable-werror
*** $ make all-gold
That should leave you with build/gold/ld-new which supports the -plugin option. Running make will additionally build build/binutils/ar and nm-new binaries supporting plugins.
Build the LLVMgold plugin. Run CMake with -DLLVM_BINUTILS_INCDIR=/path/to/binutils/include. The correct include path will contain the file plugin-api.h.
Replace the existing binutils tools in /usr/bin with the newly built gold enabled binutils tools like ld, nm, ar. It is recommended that you use soft links to back up and replace existing ld, nm, ar with the gold enabled version.
-Wl tells the linker to accept the following argument. In the example, it tells the linker to allow multiple definitions.
-plugin-opt= tells the linker to pass the following argument to the plugin.
The 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
Enable all optimizations of -O3 plus optimizations that are not valid for standard-compliant programs, such as re-ordering
operations without regard to parentheses.
Many more details are available.
On x86 systems, allows use of instructions that require the listed architecture.
Sets the compiler's inlining heuristics to an aggressive level by increasing the inline thresholds.
Passes the option-name through the compiler frontend to the optimizer.
Sets the limit at which loops will be unrolled. For example,if unroll-threshold is set to 100 then only loops with 100 or less instructions will be unrolled.
The optimization transforms the data layout of a single dimensional array to provide better cache locality by analysing the access patterns.
Sets the compiler's inlining threshold level to the value passed as argument. The inline threshold is used in the inliner heuristics to decide which function should be inlined
Use the jemalloc library, which is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support.
Generate code for a 32-bit environment. The 32-bit environment sets int, long and pointer to 32 bits and generates code that runs on any i386 system. The compiler generates x86 or IA32 32-bit ABI. The default on a 32-bit host is 32-bit ABI. The default on a 64-bit host is 64-bit ABI if the target platform specified is 64-bit, otherwise the default is 32-bit.
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).
Note:
-flto requires llvm to be build with gold-linker. The default binary releases of llvm from llvm.org do not have LLVMGold.so and so will not support -flto. To use -flto, you will have to
Download, configure and build binutils for gold with plugin support.
*** $ git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
*** $ mkdir build
*** $ cd build
*** $ ../binutils/configure --enable-gold --enable-plugins --disable-werror
*** $ make all-gold
That should leave you with build/gold/ld-new which supports the -plugin option. Running make will additionally build build/binutils/ar and nm-new binaries supporting plugins.
Build the LLVMgold plugin. Run CMake with -DLLVM_BINUTILS_INCDIR=/path/to/binutils/include. The correct include path will contain the file plugin-api.h.
Replace the existing binutils tools in /usr/bin with the newly built gold enabled binutils tools like ld, nm, ar. It is recommended that you use soft links to back up and replace existing ld, nm, ar with the gold enabled version.
-Wl tells the linker to accept the following argument. In the example, it tells the linker to allow multiple definitions.
-plugin-opt= tells the linker to pass the following argument to the plugin.
The 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
Enable all optimizations of -O3 plus optimizations that are not valid for standard-compliant programs, such as re-ordering
operations without regard to parentheses.
Many more details are available.
On x86 systems, allows use of instructions that require the listed architecture.
Sets the compiler's inlining heuristics to an aggressive level by increasing the inline thresholds.
Passes the option-name through the compiler frontend to the optimizer.
Sets the limit at which loops will be unrolled. For example,if unroll-threshold is set to 100 then only loops with 100 or less instructions will be unrolled.
The optimization transforms the data layout of a single dimensional array to provide better cache locality by analysing the access patterns.
Sets the compiler's inlining threshold level to the value passed as argument. The inline threshold is used in the inliner heuristics to decide which function should be inlined
Add the specified path to the list of paths that the linker will search for archive libraries and control scripts.
Use the jemalloc library, which is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support.
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).
Note:
-flto requires llvm to be build with gold-linker. The default binary releases of llvm from llvm.org do not have LLVMGold.so and so will not support -flto. To use -flto, you will have to
Download, configure and build binutils for gold with plugin support.
*** $ git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
*** $ mkdir build
*** $ cd build
*** $ ../binutils/configure --enable-gold --enable-plugins --disable-werror
*** $ make all-gold
That should leave you with build/gold/ld-new which supports the -plugin option. Running make will additionally build build/binutils/ar and nm-new binaries supporting plugins.
Build the LLVMgold plugin. Run CMake with -DLLVM_BINUTILS_INCDIR=/path/to/binutils/include. The correct include path will contain the file plugin-api.h.
Replace the existing binutils tools in /usr/bin with the newly built gold enabled binutils tools like ld, nm, ar. It is recommended that you use soft links to back up and replace existing ld, nm, ar with the gold enabled version.
-Wl tells the linker to accept the following argument. In the example, it tells the linker to allow multiple definitions.
-plugin-opt= tells the linker to pass the following argument to the plugin.
The 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
Turns on LLVM's (and Clang's) instrumenation based profiling.
Uses the profiling files generated from a program compiled with -fprofile-instr-generate.
Enable all optimizations of -O3 plus optimizations that are not valid for standard-compliant programs, such as re-ordering
operations without regard to parentheses.
Many more details are available.
On x86 systems, allows use of instructions that require the listed architecture.
Passes the option-name through the compiler frontend to the optimizer.
The unroll count can be specified explicitly with -unroll_count=_value_ where _value_ is a positive integer. If this value is greater than the trip count, the loop will be fully unrolled.
Sets the limit at which loops will be unrolled. For example,if unroll-threshold is set to 100 then only loops with 100 or less instructions will be unrolled.
Use the jemalloc library, which is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support.
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).
Note:
-flto requires llvm to be build with gold-linker. The default binary releases of llvm from llvm.org do not have LLVMGold.so and so will not support -flto. To use -flto, you will have to
Download, configure and build binutils for gold with plugin support.
*** $ git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
*** $ mkdir build
*** $ cd build
*** $ ../binutils/configure --enable-gold --enable-plugins --disable-werror
*** $ make all-gold
That should leave you with build/gold/ld-new which supports the -plugin option. Running make will additionally build build/binutils/ar and nm-new binaries supporting plugins.
Build the LLVMgold plugin. Run CMake with -DLLVM_BINUTILS_INCDIR=/path/to/binutils/include. The correct include path will contain the file plugin-api.h.
Replace the existing binutils tools in /usr/bin with the newly built gold enabled binutils tools like ld, nm, ar. It is recommended that you use soft links to back up and replace existing ld, nm, ar with the gold enabled version.
-Wl tells the linker to accept the following argument. In the example, it tells the linker to allow multiple definitions.
-plugin-opt= tells the linker to pass the following argument to the plugin.
The 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
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.
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. Level 2 is assumed if no value is specified (i.e. "-O". The default is "-O2".
Enables AVX2 (Advanced Vector Extensions, 2nd generation) support.
Enables the adcx instruction generation support.
Tells the optimizer to unroll loops whose number of iterations can be determined at compile time or upon entry to the loop.
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations.
Enable all optimizations of -O3 plus optimizations that are not valid for standard-compliant programs, such as re-ordering
operations without regard to parentheses.
Many more details are available.
Set the default integer and logical types to an 8 byte type. It does not promote variables with explicit KIND declaration.
Load the plugin code in file dragonegg.so, assumed to be a shared object to be dlopen'd by the compiler. In AOCC, DragonEgg is called the "AOCC Fortran Plugin".
Passes the argument list following the flag to the DragonEgg gfortran plugin. Each argument must be enclosed in quotes.
Enables splitting of long live ranges of loop induction variables which span loop boundaries. This helps reduce register pressure and can help avoid needless spills to memory and reloads from memory.
Sets the compiler's inlining threshold level to the value passed as argument. The inline threshold is used in the inliner heuristics to decide which function should be inlined. Use the option -fplugin-arg-dragonegg-llvm-option="-inline-threshold:1000" to pass this option to LLVM backend through dragonegg
Certain loops with breaks maybe 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. Use the option -fplugin-arg-dragonegg-llvm-option="-disable-vect-cmp" to pass this option to LLVM backend through dragonegg.
Use the jemalloc library, which is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support.
Instructs the compiler to link with gfortran libraries
Instructs the compiler to link with AMD-supported math library
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. Level 2 is assumed if no value is specified (i.e. "-O". The default is "-O2".
This result has been formatted using multiple flags files. The "submit command" from each of them appears next.
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:
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 effect 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 memory on the local node while "-m" specifies which node(s) to place a process memory. For full details on using numactl, please refer to your Linux documentation, 'man numactl'
Note that some versions of numactl, particularly the version found on SLES 10, we have found that the utility incorrectly interprets application arguments as it's own. For example, with the command "numactl --physcpubind=0 -l a.out -m a", numactl will interpret a.out's "-m" option as it's own "-m" option. To work around this problem, a user can 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"
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.
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.
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 and manually set the Huge Pages you can follow the below steps:
Note that further information about huge pages may be found in your Linux documentation file: /usr/src/linux/Documentation/vm/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.
OMP_NUM_THREADS
Sets the maximum number of OpenMP parallel threads applications based on OpenMP may use.
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.
LD_LIBRARY_PATH
An environment variable set to include the LLVM, JEMalloc and SmartHeap libraries used during compilation of the binaries. This environment variable setting is not needed when building the binaries on the system under test.
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.
*** 0 - Turn the process address space randomization off. This is the default for architectures that do not support this feature anyways, and kernels that are booted with the "norandmaps" parameter.
*** 1 - Make the addresses of mmap base, stack and VDSO page randomized. This, among other things, implies that shared libraries will be loaded to random addresses. Also for PIE-linked binaries, the location of code start is randomized. This is the default if the CONFIG_COMPAT_BRK option is enabled.
*** 2 - Additionally enable heap randomization. This is the default if 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.
Memory Interleaving:
DISABLED-When memory interleave is disable 4 NUMA nodes will be seen as in the case for channel interleaving but the memory will not be interleaved yet stacked next to one another. CHANNEL INTERLEAVING-Channel interleaving is also available with all configurations and is the intra-die memory interleave option and is the default setting for Dell EMC platforms. With channel interleaving the memory behind each UMC will be interleaved and seen as 1 NUMA domain per die. This will generated with 4 NUMA domains per socket. DIE INTERLEAVING-Die interleaving is available for on all configurations and is the intra-socket memory interleave option that create one NUMA domain for all the 4 dies on socket. In a 2 processor configuration this will produce 2 NUMA domains, one domain pertaining to each socket providing customers with the first option for NUMA configuration. In a one socket platform die interleaving will be the maximum option of memory interleaving, and will produce one memory domain also producing a non-NUMA configuration. SOCKET INTERLEAVING-Socket interleaving is memory interleave option meant only for inter-socket memory interleaving, and is only available with a 2 processor configurations. In this configuration memory across both sockets will be seen as a single memory domain producing a non-NUMA configuration
Virtualization technology:
When set to Enabled, the BIOS will enable processor Virtualization features and provide the virtualization support to the Operating System (OS) through the DMAR table. In general, only virtualized environments such as VMware(r) ESX (tm), Microsoft Hyper-V(r) , Red Hat(r) KVM, and other virtualized operating systems will take advantage of these features. Disabling this feature is not known to significantly alter the performance or power characteristics of the system, so leaving this option Enabled is advised for most cases.
System Profile:
When set to Custom, you can change setting of each option. Under Custom mode when C state is enabled, Monitor/Mwait should also be enabled.
CPU Power Management:
Maximum Performance is typically selected for performance-centric workloads where it is acceptable to consume additional power to achieve the highest possible performance for the computing environment. This mode drives processor frequency to the maximum across all cores (although idled cores can still be frequency reduced by C-state enforcement through BIOS or OS mechanisms if enabled). This mode also offers the lowest latency of the CPU Power Management Mode options, so is always preferred.
Memory Frequency:
Governs the BIOS memory frequency. The variables that govern maximum memory frequency include the maximum rated frequency of the DIMMs, the DIMMs per channel population, the processor choice, and this BIOS option. Additional power savings can be achieved by reducing the memory frequency, at the expense of reduced performance.
Turbo Boost:
Governs the Boost Technology. This feature allows teh processor cores to be automatically clocked up in frequency beyond the advertised processor speed. The amount of increased frequency (or 'turbo upside') one can expect from an EPYC processor depends on the fewer cores being exercised with work the higher the potential turbo upside. The potential drawback for Boost are mainly centered on increased power consumption and possible frequency jitter that can affect a small minority of latency-sensitive environments.
C States:
C States allow the processor to enter lower power states when idle. When set to Enabled (OS controlled) or when set to Autonomous (if Hardware controlled is supported), the processor can operate in all available Power States to save power, but my increase memory latency and frequency jitter.
Memory Patrol Scrub:
Patrol Scrubbing searches the memory for errors and repairs correctable errors to prevent the accumulation of memory errors. When set to Disabled, no patrol scrubbing will occur. When set to Standard Mode, the entire memory array will be scrubbed once in a 24 hour period. When set to Extended Mode, the entire memory array will be scrubbed more frequently to further increase system reliability.
Memory Refresh Rate:
The memory controller will periodically refresh the data in memory. The frequency at which memory is normally refreshed is referred to as 1X refresh rate. When memory modules are operating at a higher than normal temperature or to further increase system reliability, the refresh rate can be set to 2X, but may have a negative impact on memory subsystem performance under some circumstances.
PCI ASPM L1 Link Power Management:
When enabled, PCIe Advanced State Power Management (ASPM) can reduce overall system power
a bit while slightly reducing system performance.
NOTE: Some devices may not perform properly (they may hang or cause the system to hang)
when ASPM is enable, for this reason L1 will only be enabled for validated qualified cards.
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 v1.0.2.
Report generated on 2019-02-21 13:54:14 by SPEC CPU2017 flags formatter v5178.