SPEC CPU2017 Platform Settings for Intel-based systems

Operating System Tuning Parameters

ulimit -s <n>
Sets the stack size to n kbytes, or unlimited to allow the stack size to grow without limit.

The OS 'cpupower' utility is used to change CPU power governors settings. Available settings are:
The 'tuned' provides a number of predefined profiles for typical use cases. The 'tuned-adm' command is used to change settings of the tuned daemon. The tuned-adm command can query current settings, list available profiles, recommend a tuning profile for the system, change profiles directly, or turn off tuning. Available profiles are:
Processes are allowed to use hugepages by writing "always" to the system file/sys/kernel/mm/transparent_hugepage. Possible options are:
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.

Firmware / BIOS / Microcode Settings

Patrol Scrub
This BIOS option allows to configure the periodicity of memory scrubbing.
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 and is an important pre-requisite to enabling KTI prefetch and is a replacement for the Cluster-on-Die feature found in previous processors.
This BIOS option allows for processor performance and power optmization. Available settings are:
DCU Streamer Prefetcher
DCU (Level 1 Data Cache) streamer prefetcher is an L1 data cache prefetcher. Lightly threaded applications and some benchmarks can benefit from having the DCU streamer prefetcher enabled.

Default setting is Enable.

Last Level Cache (LLC)Prefetch
This option configures the processor last level cache (LLC) prefetch feature as a result of the non-inclusive cache architecture. The LLC prefetcher exists on top of other prefetchers that can prefetch data into the core data cache unit (DCU) and mid-level cache (MLC). In some cases, setting this option to disabled can improve performance. Typically, setting this option to enable provides better performance.

Values for this BIOS option can be:

Link disable
Four UPI links are present between the two sockets of the BullSequana SH20. Each UPI link is power consuming and is not necessary for a well localized benchmark as specCPU

Disabling three out of four links allows power saving at UPI level and increased frequency of the core part of the CPU package

The BIOS setting "Link Disable" is present for all 4 UPI ports of the 2 CPU packages.

This setting can be found in Advanced settings / Socket configuration / Uncore configuration / Uncore Per Socket Configuration / CPU Nb / CPU Nb UPI Port 0-3

Values for this BIOS option can be:

By default, the fan speed is regulated to keep the processor temperature just below the maximum To lower the processor temperature, fans are set to the maximum speed using a redfish command on the BMC.

curl -k -u "bmcLogin":"passwd" -H "Content-Type: application/json" -d '{"Oem":{"Eviden_com":{"FansFullSpeed": true}}}' -X PATCH https://"bmc ip address"/redfish/v1/Chassis/Module0/Thermal