CPU2017 Flag Description
Fujitsu PRIMERGY RX2450 M1, AMD EPYC 7552, 2.20 GHz
Test sponsored by Fujitsu
Compilers: AMD Optimizing C/C++ Compiler Suite
Base Compiler Invocation
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- clang
![[user]](https://www.spec.org/auto/cpu2017/images/user.png)
- CC, LD
-
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking.
Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
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- clang++
- CXX, LD
-
clang++ C++ compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking.
Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
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- flang
- FC, LD
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flang is a Fortran compiler which encompasses parsing, optimization, code generation, assembly, and linking. Depending on
which high-level mode setting is passed, Flang will stop before doing a full link.
-
- flang
- FC, LD
-
flang is a Fortran compiler which encompasses parsing, optimization, code generation, assembly, and linking. Depending on
which high-level mode setting is passed, Flang will stop before doing a full link.
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- clang
- CC
-
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking.
Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
-
- clang++
- CXX, LD
-
clang++ C++ compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking.
Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
-
- clang
- CC
-
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking.
Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
-
- clang++
- CXX, LD
-
clang++ C++ compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking.
Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
-
- clang
- CC
-
clang is a C compiler which encompasses preprocessing, parsing, optimization, code generation, assembly, and linking.
Depending on which high-level mode setting is passed, Clang will stop before doing a full link.
-
- flang
- FC
-
flang is a Fortran compiler which encompasses parsing, optimization, code generation, assembly, and linking. Depending on
which high-level mode setting is passed, Flang will stop before doing a full link.
Base Portability Flags
-
![[suite]](https://www.spec.org/auto/cpu2017/images/suite.png)
- EXTRA_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.
-
- EXTRA_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.
-
- EXTRA_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.
-
- EXTRA_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.
-
- EXTRA_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.
-
- EXTRA_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.
-
-
-
- EXTRA_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.
-
-
-
- EXTRA_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.
-
-
- EXTRA_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.
-
- EXTRA_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.
-
- EXTRA_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.
-
- EXTRA_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.
-
- EXTRA_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
-
-
-
-
-
-
- -O3
- COPTIMIZE
-
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.
- Includes:
-
- -ffast-math
- COPTIMIZE
-
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations that may
not conform to the IEEE-754 specifications. When this option is specified, the __STDC_IEC_559__ macro is
ignored even if set by the system headers.
-
- -march=znver2
- COPTIMIZE
-
Specify that Clang should generate code for a specific processor family member and later. For example, if you specify
-march=znver1, the compiler is allowed to generate instructions that are valid on AMD Zen processors, but
which may not exist on earlier products.
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-
-
-
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-
-
-
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-
-
-
-
- -O3
- CXXOPTIMIZE
-
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.
- Includes:
-
- -ffast-math
- CXXOPTIMIZE
-
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations that may
not conform to the IEEE-754 specifications. When this option is specified, the __STDC_IEC_559__ macro is
ignored even if set by the system headers.
-
- -march=znver2
- CXXOPTIMIZE
-
Specify that Clang should generate code for a specific processor family member and later. For example, if you specify
-march=znver1, the compiler is allowed to generate instructions that are valid on AMD Zen processors, but
which may not exist on earlier products.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- -O3
- FOPTIMIZE
-
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.
- Includes:
-
- -march=znver2
- FOPTIMIZE
-
Specify that Clang should generate code for a specific processor family member and later. For example, if you specify
-march=znver1, the compiler is allowed to generate instructions that are valid on AMD Zen processors, but
which may not exist on earlier products.
-
-
- -Mrecursive
- FOPTIMIZE
-
Allocate local variables on the stack, thus allowing recursion.
SAVEd, data-initialized, or namelist members are always allocated
statically, regardless of the setting of this switch.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- -O3
- COPTIMIZE, FOPTIMIZE
-
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.
- Includes:
-
- -ffast-math
- COPTIMIZE
-
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations that may
not conform to the IEEE-754 specifications. When this option is specified, the __STDC_IEC_559__ macro is
ignored even if set by the system headers.
-
- -march=znver2
- COPTIMIZE, FOPTIMIZE
-
Specify that Clang should generate code for a specific processor family member and later. For example, if you specify
-march=znver1, the compiler is allowed to generate instructions that are valid on AMD Zen processors, but
which may not exist on earlier products.
-
-
-
-
-
-
-
-
-
-
-
-
- -Mrecursive
- FOPTIMIZE
-
Allocate local variables on the stack, thus allowing recursion.
SAVEd, data-initialized, or namelist members are always allocated
statically, regardless of the setting of this switch.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- -O3
- COPTIMIZE, CXXOPTIMIZE
-
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.
- Includes:
-
- -ffast-math
- COPTIMIZE, CXXOPTIMIZE
-
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations that may
not conform to the IEEE-754 specifications. When this option is specified, the __STDC_IEC_559__ macro is
ignored even if set by the system headers.
-
- -march=znver2
- COPTIMIZE, CXXOPTIMIZE
-
Specify that Clang should generate code for a specific processor family member and later. For example, if you specify
-march=znver1, the compiler is allowed to generate instructions that are valid on AMD Zen processors, but
which may not exist on earlier products.
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- -O3
- COPTIMIZE, CXXOPTIMIZE, FOPTIMIZE
-
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.
- Includes:
-
- -ffast-math
- COPTIMIZE, CXXOPTIMIZE
-
Enables a range of optimizations that provide faster, though sometimes less precise, mathematical operations that may
not conform to the IEEE-754 specifications. When this option is specified, the __STDC_IEC_559__ macro is
ignored even if set by the system headers.
-
- -march=znver2
- COPTIMIZE, CXXOPTIMIZE, FOPTIMIZE
-
Specify that Clang should generate code for a specific processor family member and later. For example, if you specify
-march=znver1, the compiler is allowed to generate instructions that are valid on AMD Zen processors, but
which may not exist on earlier products.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- -Mrecursive
- FOPTIMIZE
-
Allocate local variables on the stack, thus allowing recursion.
SAVEd, data-initialized, or namelist members are always allocated
statically, regardless of the setting of this switch.
-
-
-
-
-
-
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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
-
Moderate level of optimization which enables most optimizations. This is the default when no "-O" option is
specified, or if no value is specified (i.e. "-O").
If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective.
- Includes:
-
- -O1
-
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.
Using numactl to bind processes and memory to cores
For multi-copy runs or single copy runs on systems with multiple sockets, it is advantageous to bind a process to a
particular core. Otherwise, the OS may arbitrarily move your process from one core to another. This can affect
performance. To help, SPEC allows the use of a "submit" command where users can specify a utility to use to bind
processes. We have found the utility 'numactl' to be the best choice.
numactl runs processes with a specific NUMA scheduling or memory placement policy. The policy is set for a
command and inherited by all of its children. The numactl flag "--physcpubind" specifies
which core(s) to bind the process. "-l" instructs numactl to keep a process's memory on the
local node while "-m" specifies which node(s) to place a process's memory. For full details on using
numactl, please refer to your Linux documentation, 'man numactl'
Note that some older versions of numactl incorrectly interpret application arguments as its own. For
example, with the command "numactl --physcpubind=0 -l a.out -m a", numactl will interpret
a.out's "-m" option as its own "-m" option. To work around this problem, we put
the command to be run in a shell script and then run the shell script using numactl. For example:
"echo 'a.out -m a' > run.sh ; numactl --physcpubind=0 bash run.sh"
Transparent Huge Pages (THP)
THP is an abstraction layer that automates most aspects of creating, managing, and using huge pages. THP is designed
to hide much of the complexity in using huge pages from system administrators and developers, as normal huge pages
must be assigned at boot time, can be difficult to manage manually, and often require significant changes to code in
order to be used effectively. Most recent Linux OS releases have THP enabled by default.
Linux Huge Page settings
If you need finer control you can manually set huge pages using the following steps:
- Create a mount point for the huge pages:
mkdir /mnt/hugepages
- The huge page file system needs to be mounted when the systems reboots. Add the following to a system boot
configuration file before any services are started:
mount -t hugetlbfs nodev /mnt/hugepages
- Set
vm/nr_hugepages=N in /etc/sysctl.conf where N is the maximum number of pages the
system may allocate.
- Reboot to have the changes take effect.
Note that further information about huge pages may be found in the Linux kernel documentation file
hugetlbpage.txt.
ulimit -s <n>
Sets the stack size to n kbytes, or unlimited to allow the stack size to grow without limit.
ulimit -l <n>
Sets the maximum size of memory that may be locked into physical memory.
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 that indicates the location in the filesystem of bundled libraries to use when running the
benchmark binaries.
kernel/randomize_va_space
This option can be used to select the type of process address space randomization that is used in the system, for
architectures that support this feature.
- 0 - Turn the process address space randomization off. This is the default for architectures that do not support
this feature anyway, 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.
- ulimit
-
This sets user limits of system-wide resources and can set the stack size to n kbytes, or unlimited to allow the stack size to
grow without limit. Some common ulimit commands may include:
- ulimit -s [n | unlimited]: Set the stack size to n kbytes, or unlimited to allow the stack size to grow without limit.
- ulimit -l (number): Set the maximum size that can be locked into memory.
- Kernel parameters
-
The following Linux Kernel parameters were set for better optimize performance.
- dirty_ratio: Set through "echo 8 > /proc/sys/vm/dirty_ratio". This setting is the absolute maximum amount of system memory
that can be filled with dirty pages before everything must get committed to disk.
- swappiness: The swappiness value can range from 1 to 100. A value of 100 will cause the kernel to swap out inactive processes
frequently in favor of file system performance, resulting in large disk cache sizes. A value of 1 tells the kernel to only
swap processes to disk if absolutely necessary. This can be set through a command like "echo 1 > /proc/sys/vm/swappiness"
- zone reclaim mode: Zone reclaim allows the reclaiming of pages from a zone if the number of free pages falls below a watermark
even if other zones still have enough pages available. Reclaiming a page can be more beneficial than taking the performance
penalties that are associated with allocating a page on a remote zone, especially for NUMA machines. To tell the kernel to
free local node memory rather than grabbing free memory from remote nodes, use a command like
"echo 1 > /proc/sys/vm/zone_reclaim_mode"
- Free the file system page cache: The command "echo 1> /proc/sys/vm/drop_caches" is used to free up the filesystem page cache.
- ACPI _CST C1 Declaration
-
This BIOS switch allows 3 options: "Disabled", "Enabled", and "Auto". This feature determines whether or not to declare the C1
state to OS. Default is Auto.
- cTDP
-
Configures the maximum power that the CPU will consume, up to the platform power limit. Valid values vary by CPU model. If value
outside the valid range is set, the CPU will automatically adjust the value so that it does fall within the valid range. When
increasing cTDP, additional power will only be consumed up to the Package Power Limit, which may be less than the cTDP setting.
| Model | Minimum cTDP | Maximum cTDP |
|---|
| EPYC 7502 | 180 | 200 |
| EPYC 7452 | 155 | 180 |
| EPYC 7402 | 180 | 200 |
| EPYC 7352 | 155 | 180 |
| EPYC 7302 | 155 | 180 |
| EPYC 7282 | 120 | 150 |
| EPYC 7262 | 155 | 180 |
| EPYC 7252 | 120 | 150 |
- Determinism Slider
-
This BIOS switch allows 3 options: "Auto", "Power", and "Performance". This feature is for the determinism to control performance.
"Auto" setting uses default values for deterministic performance control. "Power" setting provides predicable performance across
all processors of the same type. "Power" setting maximizes performance withing the power limits defined by cTDP.
Default is "Auto".
- DRAM Scrub Time
-
This feature controls the time between DRAM Scrubbing,
which cyclically accesses the main memory of the system in the background regardless of the operating system in order to detect and correct memory errors in a preventive way.
This BIOS switch allows 8 options: "Disabled", "1 hour", "4 hours", "8 hours", "16 hours", "24 hours", "48 hours", and "Auto".
"Disabled" option disables the feature of DRAM Scrubbing and it may result in improving the performance under certain circumstances but increases the probability of discovering memory errors in case of active accesses by the operating system.
Until these errors are correctable, the ECC technology of the memory modules ensures that the system continues to run in a stable way.
However, too many correctable memory errors increase the risk of discovering non-correctable errors, which then result in a system standstill.
- Global C-state Control
-
This BIOS switch allows 2 options: "Disabled", "Enabled, and "Auto".
This feature controls IO based C-state generation and DF C-states. Default is "Auto"
- L1 Stream HW Prefetcher
-
This BIOS switch allows 2 options: "Disabled", "Enabled, and "Auto". This feature allows enabling or disabling of L1 Stream
HW Prefetcher. Auto. Default is "Auto".
- L2 Stream HW Prefetcher
-
This BIOS switch allows 2 options: "Disabled", "Enabled, and "Auto". This feature allows enabling or disabling of L2 Stream
HW Prefetcher. Default is "Auto".
- NUMA nodes per socket
-
This BIOS switch allows 5 options: "NPS0", "NPS1", "NPS2", "NPS4", and "Auto". This feature specifies the number of desired
NUMA nodes per populated socket in the system:
- NPS0: All physical processor is a NUMA node and memory accesses are interleaved across all memory channels of two sockets together.
- NPS1: Each physical processor is a NUMA node, and memory accesses are interleaved across all memory channels
directly connected to the physical processor.
- NPS2: Each physical processor is two NUMA nodes, and memory accesses are interleaved across 4 memory channels.
- NPS4: Each physical processor is four NUMA nodes, and memory accesses are interleaved across 2 memory channels.
- Auto: Use default value. Current default is NPS1
Default is "Auto".
- Package Power Limit
-
This BIOS switch specifies the maximum power that each CPU package may consume in the system. The actual power limit is the maximum
of the Package Power Limit and cTDP.
- SMT Control
-
This BIOS switch allows 2 options: "Auto" and "Disabled". This feature allows enabling or disabling of symmetric multithreading
on processors. When enabled, each physical processor core operates as two logical processor cores. When disabled, each physical core
operates as only one logical processor core.
"Auto" enables this feature and can improve overall performance for applications that benefit from a higher processor core count.
Default is "Disabled".
- SVM Mode
-
This BIOS switch allows 2 options: "Enabled" and "Disabled". This is CPU virtualization function. With SVM enabled virtual machines
can be installed on the system. Default is "Enabled".
For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact info@spec.org
Copyright 2017-2021 Standard Performance Evaluation Corporation
Tested with SPEC CPU2017 v1.1.5.
Report generated on 2021-03-16 15:32:17 by SPEC CPU2017 flags formatter v5178.
![[benchmark]](https://www.spec.org/auto/cpu2017/images/benchmark.png)