CPU2017 Flag Description
ASUSTeK Computer Inc. ASUS RS300-E10(P11C-C/4L) Server System (3.80 GHz, Intel Xeon E-2186G)
This result has been formatted using multiple flags files.
The "default header section" from each of them appears next.
Default header section from Intel-ic19.0-official-linux64
SPEC CPU2006/CPU2017 Flag Description for the Intel(R) C++ and Fortran Compiler 19.0
for IA32 and Intel 64 applications
Copyright © 2016 Intel Corporation. All Rights Reserved.
Default header section from gcc
GNU Compiler Collection Flags
Flag descriptions for GCC, the GNU Compiler Collection
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.
Base Portability Flags
-
- -DSPEC_LP64
![[suite]](https://www.spec.org/auto/cpu2017/images/suite.png)
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
-
- -convert big_endian
![[user]](https://www.spec.org/auto/cpu2017/images/user.png)
- FPORTABILITY
-
Specifies that the format will be big endian for INTEGER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and big endian IEEE floating-point for REAL*4, REAL*8, REAL*16, COMPLEX*8,
COMPLEX*16, or COMPLEX*32.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
-
- -convert big_endian
- FPORTABILITY
-
Specifies that the format will be big endian for INTEGER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and big endian IEEE floating-point for REAL*4, REAL*8, REAL*16, COMPLEX*8,
COMPLEX*16, or COMPLEX*32.
-
- -assume byterecl
- FPORTABILITY
-
Specifies that the units for the OPEN statement RECL specifier (record length) value are in bytes for unformatted data files, not longwords (four-byte units). For formatted files, the RECL value is
always in bytes.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
Peak Portability Flags
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
-
- -convert big_endian
- FPORTABILITY
-
Specifies that the format will be big endian for INTEGER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and big endian IEEE floating-point for REAL*4, REAL*8, REAL*16, COMPLEX*8,
COMPLEX*16, or COMPLEX*32.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
-
- -convert big_endian
- FPORTABILITY
-
Specifies that the format will be big endian for INTEGER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and big endian IEEE floating-point for REAL*4, REAL*8, REAL*16, COMPLEX*8,
COMPLEX*16, or COMPLEX*32.
-
- -assume byterecl
- FPORTABILITY
-
Specifies that the units for the OPEN statement RECL specifier (record length) value are in bytes for unformatted data files, not longwords (four-byte units). For formatted files, the RECL value is
always in bytes.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
-
- -DSPEC_LP64
- PORTABILITY
-
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.
Base Optimization Flags
-
-
- -xCORE-AVX2
- COPTIMIZE
-
Code is optimized for Intel(R) processors with support for AVX2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- COPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- COPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
-
-
-
-
-
-
-
- -xCORE-AVX2
- FOPTIMIZE
-
Code is optimized for Intel(R) processors with support for AVX2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- FOPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- FOPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
-
-
- -nostandard-realloc-lhs
- EXTRA_FOPTIMIZE
-
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the
right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has
the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the
correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
-
-
-
-
- -xCORE-AVX2
- COPTIMIZE, FOPTIMIZE
-
Code is optimized for Intel(R) processors with support for AVX2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- COPTIMIZE, FOPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- COPTIMIZE, FOPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
-
-
-
- -nostandard-realloc-lhs
- EXTRA_FOPTIMIZE
-
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the
right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has
the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the
correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
-
-
-
-
- -xCORE-AVX2
- COPTIMIZE, CXXOPTIMIZE, FOPTIMIZE
-
Code is optimized for Intel(R) processors with support for AVX2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- COPTIMIZE, CXXOPTIMIZE, FOPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- COPTIMIZE, CXXOPTIMIZE, FOPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
-
- -qopenmp
- Yes
- COPTIMIZE, CXXOPTIMIZE, FOPTIMIZE
-
-
-
- -nostandard-realloc-lhs
- EXTRA_FOPTIMIZE
-
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the
right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has
the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the
correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
-
-
Peak Optimization Flags
-
- -xCORE-AVX2
- COPTIMIZE
-
Code is optimized for Intel(R) processors with support for AVX2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- COPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- COPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
-
-
-
- -prof-gen
- PASS1_FFLAGS, PASS1_LDFLAGS
-
Instrument program for profiling for the first phase of
two-phase profile guided otimization. This instrumentation gathers information
about a program's execution paths and data values but does not gather
information from hardware performance counters. The profile instrumentation
also gathers data for optimizations which are unique to profile-feedback
optimization.
-profgen:threadsafe option collects profile guided optimization data with
guards for threaded applications.
-
- -prof-use
- PASS2_FFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
-
-
- -O2
- PASS1_FOPTIMIZE
-
Enables optimizations for speed. This is the generally recommended
optimization level. This option also enables:
- Inlining of intrinsics
- Intra-file interprocedural optimizations, which include:
- inlining
- constant propagation
- forward substitution
- routine attribute propagation
- variable address-taken analysis
- dead static function elimination
- removal of unreferenced variables
- The following capabilities for performance gain:
- constant propagation
- copy propagation
- dead-code elimination
- global register allocation
- global instruction scheduling and control speculation
- loop unrolling
- optimized code selection
- partial redundancy elimination
- strength reduction/induction variable simplification
- variable renaming
- exception handling optimizations
- tail recursions
- peephole optimizations
- structure assignment lowering and optimizations
- dead store elimination
- Includes:
-
- -xCORE-AVX2
- PASS2_FOPTIMIZE
-
Code is optimized for Intel(R) processors with support for AVX2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_FOPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
-
- -no-prec-div
- PASS2_FOPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
- EXTRA_FOPTIMIZE
-
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the
right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has
the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the
correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
-
-
- -xCORE-AVX2
- FOPTIMIZE
-
Code is optimized for Intel(R) processors with support for AVX2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- FOPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- FOPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
-
-
- EXTRA_FOPTIMIZE
-
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the
right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has
the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the
correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
-
- -prof-gen
- PASS1_CFLAGS, PASS1_FFLAGS, PASS1_LDFLAGS
-
Instrument program for profiling for the first phase of
two-phase profile guided otimization. This instrumentation gathers information
about a program's execution paths and data values but does not gather
information from hardware performance counters. The profile instrumentation
also gathers data for optimizations which are unique to profile-feedback
optimization.
-profgen:threadsafe option collects profile guided optimization data with
guards for threaded applications.
-
- -prof-use
- PASS2_CFLAGS, PASS2_FFLAGS, PASS2_LDFLAGS
-
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
-
- -O2
- PASS1_COPTIMIZE, PASS1_FOPTIMIZE
-
Enables optimizations for speed. This is the generally recommended
optimization level. This option also enables:
- Inlining of intrinsics
- Intra-file interprocedural optimizations, which include:
- inlining
- constant propagation
- forward substitution
- routine attribute propagation
- variable address-taken analysis
- dead static function elimination
- removal of unreferenced variables
- The following capabilities for performance gain:
- constant propagation
- copy propagation
- dead-code elimination
- global register allocation
- global instruction scheduling and control speculation
- loop unrolling
- optimized code selection
- partial redundancy elimination
- strength reduction/induction variable simplification
- variable renaming
- exception handling optimizations
- tail recursions
- peephole optimizations
- structure assignment lowering and optimizations
- dead store elimination
- Includes:
-
- -xCORE-AVX2
- PASS2_COPTIMIZE, PASS2_FOPTIMIZE
-
Code is optimized for Intel(R) processors with support for AVX2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
-
- -O3
- PASS2_COPTIMIZE, PASS2_FOPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
-
- -no-prec-div
- PASS2_COPTIMIZE, PASS2_FOPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
- -qopenmp
- Yes
- PASS2_COPTIMIZE, PASS2_FOPTIMIZE
-
-
-
- EXTRA_FOPTIMIZE
-
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the
right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has
the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the
correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
-
- -xCORE-AVX2
- COPTIMIZE, FOPTIMIZE
-
Code is optimized for Intel(R) processors with support for AVX2 instructions.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
-
-
- -O3
- COPTIMIZE, FOPTIMIZE
-
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets.
- Includes:
-
- -no-prec-div
- COPTIMIZE, FOPTIMIZE
-
(disable/enable[default] -prec-div)
-no-prec-div enables optimizations that give slightly less precise results
than full IEEE division.
When you specify -no-prec-div along with some optimizations, such as
-xN and -xB (Linux) or /QxN and /QxB (Windows),
the compiler may change floating-point division computations into
multiplication by the reciprocal of the denominator.
For example, A/B is computed as A * (1/B) to improve the speed of the
computation.
However, sometimes the value produced by this transformation is
not as accurate as full IEEE division. When it is important to have fully
precise IEEE division, do not use -no-prec-div.
This will enable the default -prec-div and the result will be more accurate,
with some loss of performance.
-
-
-
-
-
-
- EXTRA_FOPTIMIZE
-
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the
right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has
the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the
correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
Implicitly Included Flags
This section contains descriptions of flags that were included implicitly
by other flags, but which do not have a permanent home at SPEC.
-
- -O2
-
Enables optimizations for speed. This is the generally recommended
optimization level. This option also enables:
- Inlining of intrinsics
- Intra-file interprocedural optimizations, which include:
- inlining
- constant propagation
- forward substitution
- routine attribute propagation
- variable address-taken analysis
- dead static function elimination
- removal of unreferenced variables
- The following capabilities for performance gain:
- constant propagation
- copy propagation
- dead-code elimination
- global register allocation
- global instruction scheduling and control speculation
- loop unrolling
- optimized code selection
- partial redundancy elimination
- strength reduction/induction variable simplification
- variable renaming
- exception handling optimizations
- tail recursions
- peephole optimizations
- structure assignment lowering and optimizations
- dead store elimination
- Includes:
-
- -O1
-
Enables optimizations for speed and disables some optimizations that increase code size and affect speed.
To limit code size, this option:
- Enables global optimization; this includes data-flow analysis,
code motion, strength reduction and test replacement, split-lifetime
analysis, and instruction scheduling.
- Disables intrinsic recognition and intrinsics inlining.
The O1 option may improve performance for applications with very large
code size, many branches, and execution time not dominated by code within loops.
-O1 sets the following options:
-funroll-loops0, -fno-builtin, -mno-ieee-fp, -fomit-framepointer, -ffunction-sections, -ftz
- Includes:
-
-
-
-
-
-
This result has been formatted using multiple flags files.
The "submit command" from each of them appears next.
Submit command from Intel-ic19.0-official-linux64
SPEC CPU2006/CPU2017 Flag Description for the Intel(R) C++ and Fortran Compiler 19.0
for IA32 and Intel 64 applications
- submit= MYMASK=`printf '0x%x' $((1<<$SPECCOPYNUM))`; /usr/bin/taskset $MYMASK $command
- When running multiple copies of benchmarks, the SPEC config file feature submit is used to cause individual jobs to be bound to
specific processors. This specific submit command, using taskset, is used for Linux64 systems without numactl.
Here is a brief guide to understanding the specific command which will be found in the config file:
- /usr/bin/taskset [options] [mask] [pid | command [arg] ... ]:
taskset is used to set or retreive the CPU affinity of a running
process given its PID or to launch a new COMMAND with a given CPU
affinity. The CPU affinity is represented as a bitmask, with the
lowest order bit corresponding to the first logical CPU and highest
order bit corresponding to the last logical CPU. When the taskset
returns, it is guaranteed that the given program has been scheduled
to a specific, legal CPU, as defined by the mask setting.
- [mask]: The bitmask (in hexadecimal) corresponding to a specific
SPECCOPYNUM. The specific example above, computes this mask value in the variable $MYMASK.
The value of this mask for the first copy of a
rate run will be 0x00000001, for the second copy of the rate will
be 0x00000002 etc. Thus, the first copy of the rate run will have a
CPU affinity of CPU0, the second copy will have the affinity CPU1
etc.
- $command: Program to be started, in this case, the benchmark instance to be started.
- submit= numactl --localalloc --physcpubind=$SPECCOPYNUM $command
- When running multiple copies of benchmarks, the SPEC config file feature submit is used to cause individual jobs to be bound to
specific processors. This specific submit command is used for Linux64 systems with support for numactl.
Here is a brief guide to understanding the specific command which will be found in the config file:
- syntax: numactl [--interleave=nodes] [--preferred=node] [--physcpubind=cpus] [--cpunodebind=nodes] [--membind=nodes] [--localalloc] command args ...
- 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.
- "--localalloc" instructs numactl to keep a process memory on the local node while "-m" specifies which node(s) to place a process memory.
- "--physcpubind" specifies which core(s) to bind the process. In this case, copy 0 is bound to processor 0 etc.
- For full details on using numactl, please refer to your Linux documentation, 'man numactl'
Submit command from gcc
GNU Compiler Collection Flags
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:
- syntax: numactl [--interleave=nodes] [--preferred=node] [--physcpubind=cpus] [--cpunodebind=nodes]
[--membind=nodes] [--localalloc] command args ...
- 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.
- --localalloc instructs numactl to keep a process memory on the local node while -m specifies which node(s) to
place a process memory.
- --physcpubind specifies which core(s) to bind the process. In this case, copy 0 is bound to processor 0
etc.
- For full details on using numactl, please refer to your Linux documentation, man numactl
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:
- submit= causes the SPEC tools to use this line when submitting jobs.
- echo ...> dobmk causes the generated commands to be written to a file, namely
dobmk.
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:
- $BIND: a reference to a value from the bind line, a line of the form
"bind = n n n n", where each "n" is a processor number. See http://www.spec.org/cpu2017/Docs/config.html#bind
for details on this feature.
- $$: the current process id
- $SPECCOPYNUM: the SPEC tools-assigned number for this copy of the benchmark.
- psrinfo: find out what processors are available
- grep on-line: search the psrinfo output for information regarding on-line cpus
- expr: Calculate simple arithmetic expressions. For example, the effect of binding jobs to a
(quote-resolved) expression such as:
expr ( $SPECCOPYNUM / 4 ) * 8 + ($SPECCOPYNUM % 4 ) )
would be to send the jobs to processors whose numbers are:
0,1,2,3, 8,9,10,11, 16,17,18,19 ...
- awk...print \$1: Pick out the line corresponding to this copy of the benchmark and use the CPU
number mentioned at the start of this line.
- sh dobmk actually runs the benchmark.
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.
Sw environment from Intel-ic19.0-official-linux64
SPEC CPU2006/CPU2017 Flag Description for the Intel(R) C++ and Fortran Compiler 19.0
for IA32 and Intel 64 applications
- numactl --interleave=all "runspec command"
- Launching a process with numactl --interleave=all sets the memory interleave policy so that memory will be allocated using round robin on nodes.
When memory cannot be allocated on the current interleave target fall back to other nodes.
- KMP_STACKSIZE
- Specify stack size to be allocated for each thread.
- KMP_AFFINITY
- Syntax: KMP_AFFINITY=[<modifier>,...]<type>[,<permute>][,<offset>]
The value for the environment variable KMP_AFFINITY affects how the threads from an auto-parallelized program are scheduled across processors.
It applies to binaries built with -qopenmp and -parallel (Linux and Mac OS X) or /Qopenmp and /Qparallel (Windows).
modifier:
granularity=fine Causes each OpenMP thread to be bound to a single thread context.
type:
compact Specifying compact assigns the OpenMP thread <n>+1 to a free thread context as close as possible to the thread context where the <n> OpenMP thread was placed.
scatter Specifying scatter distributes the threads as evenly as possible across the entire system.
permute: The permute specifier is an integer value controls which levels are most significant when sorting the machine topology map. A value for permute forces the mappings to make the specified number of most significant levels of the sort the least significant, and it inverts the order of significance.
offset: The offset specifier indicates the starting position for thread assignment.
Please see the Thread Affinity Interface article in the Intel Composer XE Documentation for more details.
- Example: KMP_AFFINITY=granularity=fine,scatter
Specifying granularity=fine selects the finest granularity level and causes each OpenMP or auto-par thread to be bound to a single thread context.
This ensures that there is only one thread per core on cores supporting HyperThreading Technology
Specifying scatter distributes the threads as evenly as possible across the entire system.
Hence a combination of these two options, will spread the threads evenly across sockets, with one thread per physical core.
- Example: KMP_AFFINITY=compact,1,0
Specifying compact will assign the n+1 thread to a free thread context as close as possible to thread n.
A default granularity=core is implied if no granularity is explicitly specified.
Specifying 1,0 sets permute and offset values of the thread assignment.
With a permute value of 1, thread n+1 is assigned to a consecutive core. With an offset of 0, the process's first thread 0 will be assigned to thread 0.
The same behavior is exhibited in a multisocket system.
- OMP_NUM_THREADS
- Sets the maximum number of threads to use for OpenMP* parallel regions if no
other value is specified in the application. This environment variable
applies to both -qopenmp and -parallel (Linux and Mac OS X) or /Qopenmp and /Qparallel (Windows).
Example syntax on a Linux system with 8 cores:
export OMP_NUM_THREADS=8
- Set stack size to unlimited
- The command "ulimit -s unlimited" is used to set the stack size limit to unlimited.
- Free the file system page cache
- The command "echo 1> /proc/sys/vm/drop_caches" is used to free up the filesystem page cache.
Red Hat Specific features
- Transparent Huge Pages
- On RedHat EL 6 and later, Transparent Hugepages increase the memory page size from 4 kilobytes to 2 megabytes. Transparent Hugepages provide significant performance advantages on systems with highly contended resources and large memory workloads.
If memory utilization is too high or memory is badly fragmented which prevents hugepages being allocated, the kernel will assign smaller 4k pages instead.
Hugepages are used by default unless the /sys/kernel/mm/redhat_transparent_hugepage/enabled field is changed from its RedHat EL6 default of 'always'.
Sw environment from gcc
GNU Compiler Collection 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 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.
- Race To Halt (RTH):
-
Enable RTH will dynamically increase CPU frequency in order to enter Package C-State faster to reduce overall power.
- Intel VT for Directed I/O (VT-d):
-
Enable/Disable Intel Virtualization Technology for Directed I/O (VT-d) by reporting the I/O device assignment to VMM through DMAR ACPI Tables.
- Software Guard Extensions (SGX):
-
Intel Software Guard Extensions is an extension to Intel architecture. With new CPU instructions and platform enhancements, enable this technology allows capable applications to create private areas to protect sensitive information.
Sensitive information is protected even when attackers has full control of the platform.
- Hardware Prefetcher:
-
Enable Hardware Prefetcher can automatically analyze the processor's requirements and prefetch data and instructions from the memory into the Level 2 cache that are likely to be required in the near future. This reduces the latency associated with memory reads.
- Adjacent Cache Line Prefetch:
-
When enabled, two 64-byte cache lines are fetched into a 128-byte sector, regardless of whether the additional cache line has been requested or not. If this prefetcher is disabled, only one cache line (64 bytes) is collected, which contains the data required by the processor.
- SR-IOV Support:
-
In virtualization, single root input/output virtualization or SR-IOV is a specification that allows the isolation of the PCI Express resources for manageability and performance reasons.
A single physical PCI Express can be shared on a virtual environment using the SR-IOV specification.
If system has SR-IOV capable PCIe Devices, this option Enables or Disables Single Root IO Virtualization Support.
- Advanced Encryption Standard (AES):
-
These instructions enable fast and secure data encryption and decryption, using the Advanced Encryption Standard (AES) which is defined by FIPS Publication number 197.
For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact info@spec.org
Copyright 2017-2019 Standard Performance Evaluation Corporation
Tested with SPEC CPU2017 v1.0.5.
Report generated on 2019-01-22 16:44:19 by SPEC CPU2017 flags formatter v5178.
![[benchmark]](https://www.spec.org/auto/cpu2017/images/benchmark.png)