CPU2017 Flag Description
xFusion FusionServer 5288 V7 (Intel Xeon Platinum 8558)

Copyright © 2016 Intel Corporation. All Rights Reserved.

Base Compiler Invocation

C benchmarks

C++ benchmarks

Fortran benchmarks

Benchmarks using both Fortran and C

Benchmarks using both C and C++

Benchmarks using Fortran, C, and C++

Peak Compiler Invocation

C benchmarks

C++ benchmarks

Fortran benchmarks

Benchmarks using both Fortran and C

Benchmarks using both C and C++

Benchmarks using Fortran, C, and C++

Base Portability Flags

503.bwaves_r

507.cactuBSSN_r

508.namd_r

510.parest_r

511.povray_r

519.lbm_r

521.wrf_r

526.blender_r

527.cam4_r

538.imagick_r

544.nab_r

549.fotonik3d_r

554.roms_r

Peak Portability Flags

503.bwaves_r

507.cactuBSSN_r

508.namd_r

510.parest_r

511.povray_r

519.lbm_r

521.wrf_r

526.blender_r

527.cam4_r

538.imagick_r

544.nab_r

549.fotonik3d_r

554.roms_r

Base Optimization Flags

C benchmarks

C++ benchmarks

Fortran benchmarks

Benchmarks using both Fortran and C

Benchmarks using both C and C++

Benchmarks using Fortran, C, and C++

Peak Optimization Flags

C benchmarks

519.lbm_r

538.imagick_r

544.nab_r

C++ benchmarks

508.namd_r

510.parest_r

Fortran benchmarks

503.bwaves_r

549.fotonik3d_r

554.roms_r

Benchmarks using both Fortran and C

Benchmarks using both C and C++

511.povray_r

526.blender_r

Benchmarks using Fortran, C, and C++

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.

Commands and Options Used to Submit Benchmark Runs

submit= MYMASK=`printf '0x%x' $((1<<$SPECCOPYNUM))`; /usr/bin/taskset $MYMASK $command
When running multiple copies of benchmarks, the SPEC config file feature submit is used to cause individual jobs to be bound to specific processors. This specific submit command, using taskset, is used for Linux64 systems without numactl.
Here is a brief guide to understanding the specific command which will be found in the config file:
submit= numactl --localalloc --physcpubind=$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:

Shell, Environment, and Other Software Settings

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
OMP_STACKSIZE
The OMP_STACKSIZE environment variable controls the size of the stack for threads created by the OpenMP implementation
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 3> /proc/sys/vm/drop_caches" is used to free up the filesystem page cache as well as reclaimable slab objects like dentries and inodes.
MALLOC_CONF
Used for Jemalloc tuning at runtime. MALLOC_CONF=retain:true will retain unused virtual memory for later resue rather than discarding it.

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'.

Operating System Tuning Parameters

cpupower frequency-set
cpupower utility is a collection of tools for power efficiency of processor. frequency-set sub-command controls settings for processor frequency. "-g [governor]" specifies a policy to select processor frequency. The performance governor statically sets frequency of the processor cores specified by "-c" option to the highest possible for maximum performance.
cpupower idle-set
idle-set sub-command of cpupower utility controls a processor idle state (C-state) of the kernel. "-d [state_no]>" option disables a specific processor idle state. Disabling idle state can reduce the idle-wakeup delay, but it results in substantially higher power consumption. By default, processor idle states of all CPU cores are set.
irqbalance
Disabled through "service irqbalance stop". Depending on the workload involved, the irqbalance service reassigns various IRQ's to system CPUs. Though this service might help in some situations, disabling it can also help environments which need to minimize or eliminate latency to more quickly respond to events.
isolcpus
This kernel option excludes a specified processor from load balancing by the kernel scheduler. This prevents the scheduler from scheduling any user-space threads on this processor.
nohz_full
This kernel option sets adaptive tick mode (NOHZ_FULL) to specified processors. Since the number of interrupts is reduced to ones per second, latency-sensitive applications can take advantage of it.
numa_balancing
This OS setting controls automatic NUMA balancing on memory mapping and process placement. Setting 0 disables this feature. It is enabled by default (1).
sched_latency_ns
This OS setting configures targeted preemption latency for CPU bound tasks. The default value is 24000000 (ns).
sched_migration_cost_ns
Amount of time after the last execution that a task is considered to be "cache hot" in migration decisions. A "hot" task is less likely to be migrated to another CPU, so increasing this variable reduces task migrations. The default value is 500000 (ns).
sched_min_granularity_ns
This OS setting controls the minimal preemption granularity for CPU bound tasks. As the number of runnable tasks increases, CFS(Complete Fair Scheduler), the scheduler of the Linux kernel, decreases the timeslices of tasks. If the number of runnable tasks exceeds sched_latency_ns/sched_min_granularity_ns, the timeslice becomes number_of_running_tasks * sched_min_granularity_ns. The default value is 10000000(ns).
sched_wakeup_granularity_ns
This OS setting controls the wake-up preemption granularity. Increasing this variable reduces wake-up preemption, reducing disturbance of compute bound tasks. Lowering it improves wake-up latency and throughput for latency critical tasks, particularly when a short duty cycle load component must compete with CPU bound components. The default value is 15000000 (ns).

Firmware / BIOS / Microcode Settings

Hardware Prefetcher (Default = Enabled)

This BIOS option allows the enabling/disabling of a processor mechanism to prefetch data into the cache according to a pattern-recognition algorithm In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking to verify improved performance in their environment.

Turbo Mode (Default = Enabled)

Intel Turbo boost Technology, Enabling this option allows the processor cores to automatically increase its frequency and increasing performance if it is running below power, temperature.

Enable LP [Global] (Default = Enabled)

The Intel Hyper-Threading knob has been renamed Enable LP [Global] to represent the number of logical processors (LP). Enabling this option allows to use processor resources more efficiently, enabling multiple threads to run on each core and increases processor throughput, improving overall performance on threaded software.

ALL LPs: Hyper-Threading is enabled, each physical processor core functions as two logical processor cores.

Single LP: Run a single logical processor per core.

Performance Profile (Default = Custom)

Values for this BIOS setting can be:

Custom: Allows the user to setup all of the BIOS options according to their requirement.

Performance: Maximize the performance of the server.

Efficiency: Maximize the power efficiency of the server.

Load Balance: The system's performance and power consumption will be adjusted automatically according to the loading.

CPU C6 Report (Default = Disabled)

Enable or disable reporting of the CPU C6 State (ACPI C3) to the OS.

Enhanced Halt State (C1E) (Default = Disabled)

When set to Enabled, the processor is allowed to switch to nimimum performance and save power when idle.

Sub NUMA Cluster（SNC）(Default = Disabled)

Sub NUMA Clustering (SNC) is a feature for breaking up the LLC into disjoint clusters based on address range,with each cluster bound to a subset of the memory controllers in the system.It improves average latency to the LLC.

Values for this BIOS option can be:

Disabled: SNC disabled will support 1-cluster and 4-way IMC interleave.

Enable SNC2 (2-clusters): SNC2 Enabled supports 2-clusters SNC and 2-way IMC interleave.

Enable SNC4 (4-clusters): SNC4 Enabled supports 4-clusters SNC and 1-way IMC interleave.

Last Level Cache (LLC) Prefetch (Default = Enabled)

The last level cache (LLC) prefetch is a prefetcher added to the Intel Xeon Scalable processor family as a result of the non-inclusive cache architecture. The LLC prefetcher is an additional prefetch mechanism on top of the existing prefetchers that prefetch data into the core Data Cache Unit (DCU) and Mid-Level Cache (MLC or second-level cache (L2)). Enabling LLC prefetch gives the core prefetcher the ability to prefetch data directly into the LLC without necessarily filling into the L1 and L2 cache. In some cases, setting this option to disabled can improve performance.

Values for this BIOS option can be:

Disabled: Disables the LLC prefetcher. The other core prefetchers are unaffected.

Enabled: Gives the core prefetcher the ability to prefetch data directly to the LLC.

Adaptive Double Device Data Correction (ADDDC) Sparing (Default = Enabled)

Adaptive Double Device Data Correction (ADDDC), which is an enhanced feature to DDDC. This function is used to correct data errors on two memory particles, ADDDC still has single-particle multi-bit error correction capability after the first particle failure occurs and is replaced.

Values for this BIOS option can be:

Enabled: Enable the ADDDC Sparing function.

Disabled: Disable the ADDDC Sparing function.

LLC dead line alloc (Default = Enabled)

LLC dead line allocation. The processor marks the row replaced by the MLC as dead, indicating that the row will not be read again. This function is used to set the allocation policy for the data marked as dead in the LLC.

Values for this BIOS option can be:

Enabled: Allows the LLC to fill dead lines into the LLC if there is free space.

Disabled: The dead lines are dropped and are never filled into the LLC, saving the LLC space.

Stale AtoS (Default = Auto)

The in-memory directory has three states: invalid (I), snoopAll (A), and shared (S). Invalid (I) state means the data is clean and does not exist in any other socket`s cache. The snoopAll (A) state means the data may exist in another socket in exclusive or modified state. Shared (S) state means the data is clean and may be shared across one or more socket`s caches. When doing a read to memory, if the directory line is in the A state we must snoop all the other sockets because another socket may have the line in modified state. If this is the case, the snoop will return the modified data. However, it may be the case that a line is read in A state and all the snoops come back a miss. This can happen if another socket read the line earlier and then silently dropped it from its cache without modifying it.

Values for this BIOS option can be:

Auto: The SnoopAll (A) state is used by default. During uncore post MRC, the state is reconfigured based on the setup knob, number of sockets, and BPS memory.

Enabled: The SnoopAll (A) state is changed to the Shared (S) state.

Disabled: The SnoopAll (A) state is used.

Flag description origin markings:

[user] Indicates that the flag description came from the user flags file.
[suite] Indicates that the flag description came from the suite-wide flags file.
[benchmark] Indicates that the flag description came from a per-benchmark flags file.

The flags files that were used to format this result can be browsed at
http://www.spec.org/cpu2017/flags/xFusion-Platform-Settings-EMR-V1.1.html,
http://www.spec.org/cpu2017/flags/Intel-ic2024-official-linux64.html.

You can also download the XML flags sources by saving the following links:
http://www.spec.org/cpu2017/flags/xFusion-Platform-Settings-EMR-V1.1.xml,
http://www.spec.org/cpu2017/flags/Intel-ic2024-official-linux64.xml.

For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact info@spec.org
Copyright 2017-2024 Standard Performance Evaluation Corporation
Tested with SPEC CPU2017 v1.1.9.
Report generated on 2024-07-17 11:48:06 by SPEC CPU2017 flags formatter v5178.