SPEC CPU2006 software OS and BIOS Settings Descriptions for Huawei Platform systems

Operating System Tuning Parameters

Install only the relevant files

Select only test related files when installing the operating system,So that many services are not installed, this will reduce the consumption of resources by the operating system itself. In accordance with the following methods to install the operating system: 1.The software installation mode was selected 'Customize now'. 2.Next,In 'base System' column, We choose the following installation package,'Base','Compatibility Libraries', 'Java Platform','Large Systems Performance','Performance Tools','Perl Support'.In 'Development' column, We choose the following installation package,'Development tools'.That is all the installation package.

HUGETLB_MORECORE

Set this environment variable to "yes" to enable applications to use large pages.

LD_PRELOAD=/usr/lib64/libhugetlbfs.so

Setting this environment variable is necessary to enable applications to use large pages.

modprobe acpi_cpufreq

Loads the CPUFreq driver which utilizes the ACPI processor performance states and supports Intel Enhanced SpeedStep. This allows the OS to control processor frequency (including turbo boost, when turbo mode is enabled in BIOS) via adjustment of P-state settings.

Cpufreq setting

cpupower frequency-set" provides a simplified mechanism to adjust processor frequencies when cpu frequency scaling is enabled in the OS. See the cpupower-frequency-set man page for details.Here is a brief description of options used in the config file. By default, settings are applied to all logical cpus in the system.Frequencies can be passed in Hz, kHz (default), MHz, GHz, or THz by postfixing the value with the desired unit name, without any space. Available frequencies and governors can be determined with "cpupower frequency-info".

Tmpfs filesystem setting

Tmpfs is a file system which keeps all files in virtual memory.A tmpfs file system will go to swap if memory pressure demands real memory for applications. This can have a very negative effect on the I/O load and system performance

Process tunning setting

Each process is assigned a time period, known as its time slice, that is the time allowed to run the process. Increse the process time slice can have a positive effect on the calculated sensitivity task. The related kernel parameters are sched_wakeup_granularity_ns, sched_min_granularity_ns, etc.

Transparent Huge Pages

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.

On RedHat EL6 and later, Transparent Hugepages are used by default if /sys/kernel/mm/redhat_transparent_hugepage/enabled is set to always. The default value is always.

On SUSE SLES11 and later, Transparent Hugepages are used by default if /sys/kernel/mm/transparent_hugepage/enabled is set to always. The default value is always.


Firmware / BIOS / Microcode Settings

Hardware Prefetch

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.

Adjacent Sector Prefetch

This BIOS option allows the enabling/disabling of a processor mechanism to fetch the adjacent cache line within a 128-byte sector that contains the data needed due to a cache line miss.In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking o verify improved performance in their environment.

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.

Intel Hyper Threading Technology:

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.

Power Efficiency Mode (Default=Custom)

Values for this BIOS setting can be: Efficiency: Maximize the power efficiency of the server,Performance:Maximize the performance of the server, Custom:Allows the user to customize power and performance related options individually.

DRAM Maintenace (Default=Auto)

Values for this BIOS setting can be: Auto: System can configures DRAM maintenace mode to pTRR mode or TRR mode,Manual:Allows the user to customize DRAM maintenace mode related options individually(pTRR or TRR mode).Disabled:not use any kind of DRAM maintenace mode.We strongly recommend using 'Auto' normally.

Lockstep Memory Mode (Default=Enabled)

Values for this BIOS setting can be: Lockstep memory mode uses two memory channels at a time and provides an even higher level of protection.You can adjust the mode to disabled.

cooling Configuration

The Baseboard Management Controller allows the user to adjust the fan speed manually,If the server is in a stressful environment, the CPU have high temperature, you can adjust the fan speed to 100%.

Memory Power Saving

Selects the memory power saving mode, Depends on the selected mode, the Power Down clock mode, CKE, and IBT are intialized accordingly, disable this featrue will keep memory in high performance mode. We strongly recommend using 'Enabled'normally.

C-State

Core C3, Core C6 can be disabled for latency-sensitive applications in order to minimize latency, but disable Core C-states can also significantly limit the amount of turbo when a low number of cores are active,C3 and C6 are recommended to enable in SPEC CPU benchmark.

VT Support

If virtualization is not used, this option should be set to "Disabled", this can result in slight performance liftings and energy savings

QPI Snoop Configuration

There are 3 snoop mode options for how to maintain cache coherency across the Intel QPI fabric, each with varying memory latency and bandwidth characteristics depending on how the snoop traffic is generated.

Cluster on Die (COD) mode logically splits a socket into 2 NUMA domains that are exposed to the OS with half the amount of cores and LLC assigned to each NUMA domain in a socket. This mode utilizes an on-die directory cache and in memory directory bits to determine whether a snoop needs to be sent. Use this mode for highly NUMA optimized workloads to get the lowest local memory latency and highest local memory bandwidth for NUMA workloads.

In Home Snoop and Early Snoop modes, snoops are always sent , they just originate from different places: the caching agent (earlier) in Early Snoop mode and the home agent (later) in Home Snoop mode.

Use Home Snoop mode for NUMA workloads that are memory bandwidth sensitive and need both local and remote memory bandwidth.

Use Early Snoop mode for workloads that are memory latency sensitive or for workloads that benefit from fast cache-to-cache transfer latencies from the remote socket. Snoops are sent out earlier, which is why memory latency is lower in this mode.

CPU C1E Support

TEnabling this option which is the default allows the processor to transmit to its minimum frequency when entering the power state C1. If the switch is disabled the CPU stays at its maximum frequency in C1. Because of the increase of power consumption users should only select this option after performing application benchmarking to verify improved performance in their environment.

Memory Patrol Scrub

This BIOS option allows the enabling/disabling of Memory Periodic Patrol Scrubber. The Memory Periodic Patrol Scrubber corrects memory soft errors so that, over the length of the system runtime, the risk of producing multi-bit and uncorrectable errors is reduced.