SPEC CPU2017 Flag Description for NEC Server Platform

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.


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.


This OS setting controls automatic NUMA balancing on memory mapping and process placement. Setting 0 disables this feature. It is enabled by default (1).


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.

Tuning Kernel parameters:

The following Linux Kernel parameters were tuned to better optimize performance of some areas of the system:

Firmware / BIOS / Microcode Settings

Memory RAS Mode:

This server has "SDDC Mode","ADDDC Mode", "Spare Mode", "Full Mirror Mode", "Addr Mirror Mode", "Reliable Memory Mode", and "Memory Scrubbing Function" as memory RAS functions.


Set Enable/Disable of Intel (R) VT-x which is the processor virtualization support HW function of Intel. This setting item is displayed only when the processor supporting this function is displayed. You can not change the setting when Intel TXT Support is set to [Enabled].

Processor C6 Report:

Set Enable/Disable of the C6 State transition function by OS.

DCU Streamer Prefetch:

Set [enable / disable] of DCU Stremer prefetcher of processor.

OS Performance Tuning:

Set whether or not to allow Performance Tuning by OS.

Energy Performance:

Set the operation of the processor to performance priority or power saving priority. This item is displayed only when 'OS Performance Tuning' is set to Disabled.

Dead Line LLC Allocation:

Set Enable/Disable for MLC to LLC movement.

Patrol Scrub:

Activate the patrol scrubbing function.

Memory P.E. Retry:

Set [Enable / Disable] for DDR4 CMD / ADDR Parity Error Retry function.

Sub NUMA Clustering (SNC):

SNC breaks up the last level cache (LLC) into disjoint clusters based on address range, with each cluster bound to a subset of the memory controllers in the system. SNC improves average latency to the LLC and memory. SNC is a replacement for the cluster on die (COD) feature found in previous processor families. For a multi-socketed system, all SNC clusters are mapped to unique NUMA domains. Set Enable/Disable of Sub NUMA Clustering function. This item is displayed only when a processor supporting this function is installed.