Select "minimal" mode when installing the operating system,so that many services are not installed,this will reduce the consumption of resources by the operating system itself. And then only install necessary files of cpu test by yum.
Setting this environment variable to "performance" to enable cores to run at performance mode.
"scaling_governor" is a configuration file in Linux's "cpufreq" model. There are five mode in "scaling_governor" which are performance, powersave, userspace, ondemand, and conservative.
Performance: Lock the CPU's frequency at top speed without adjusting dynamically,which may require additional power;
Powersave: CPU will work at the minimum frequency;
Userspace: Provides the corresponding interface for the user-mode application program to adjust the frequency of CPU;
Ondemand: Quick dynamic adjustment of CPU frequency on demand, and will reach the maximum frequency;
Conservative: Frequency will be adjusted on demand.
We use "cpupower frequency-set -g performance" to set this environment variable to "performance".
A commandline interface for switching between different tuning profiles available in supported Linux distributions. The distribution provided profiles are located in /usr/lib/tuned and the user defined profiles in /etc/tuned. To set a profile, one can issue the command "tuned-adm profile (profile_name)". Below are details about some relevant profiles.
tuned-adm command line utility allows user to switch between user definable tuning profiles.[active, profile (name), off]
throughput-performance: For typical throughput performance tuning. Disables power saving mechanisms and enables sysctl settings that improve the throughput performance of disk and network I/O. CPU governor is set to performance and CPU energy performance bias is set to performance. Disk readahead values are increased;
latency-performance: For low latency performance tuning. Disables power saving mechanisms. CPU governor is set to performance and locked to the low C states. CPU energy performance bias to performance;
balanced: Default profile provides balanced power saving and performance. It enables CPU and disk plugins of tuned and makes the conservative governor is active and also sets the CPU energy performance bias to normal. It also enables power saving on audio and graphics card;
powersave: Maximal power saving for whole system. It sets the CPU governor to ondemand governor and energy performance bias to powersave. It also enable power saving on USB, SATA, audio and graphics card;
We use "tuned-adm profiel throughput-performance" to set this environment variable to "throughput-performance".
Transparent Hugepages can be used to increase the memory page size from 4 kilobytes to 2 megabytes. THP 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.
Examples:
echo always >/sys/kernel/mm/transparent_hugepage/enabled
echo madvise >/sys/kernel/mm/transparent_hugepage/enabled
echo never >/sys/kernel/mm/transparent_hugepage/enabled
Refer to the OS documentation for more details on THP.
This BIOS option allows for processor performance and power optmization. Available settings are:
Performance: High performance with less need for power saving.
Balanced Performance (Default Setting): Provides optimal performance efficiency.
Balanced Power: Provides optimal power efficiency.
Power: High power saving with less need for performance.
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. Hardware Prefetching is typically accomplished by having a dedicated hardware mechanism in the processor that watches the stream of instructions or data being requested by the executing program, recognizes the next few elements that the program might need based on this stream and prefetches into the processor's cache. The default setting is Enable.
Enabling this option allows the processor cores to automatically increase its frequency and increasing performance if it is running below power, temperature.The default setting is Enable.
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.The default setting is Enable.
This BIOS setting allows the memory to be clocked to the Specific frequency. Default is "Auto"
Examples:
Auto: the memory will running at the highest supported frequency
4400: the memory will running at 4400Mhz
4800: the memory will running at 4800Mhz
If virtualization is not used, this option should be set to "Disabled", this can result in slight performance liftings and energy savings.The default setting is Enable.
Enabling this option, which is the default, allows the processor to transition 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 enable this option after performing application benchmarking to verify improved performance in their environment.
This switch allows the configuration of the UPI link speed. Default is auto, which configures the optimal link speed automatically. Values can be: 8GT/s and 9.6GT/s and 10.4GT/s.
This BIOS option controls the interleaving between the Integrated Memory Controllers (IMCs), Memory could be interleaved across sockets, memory controllers, DDR channels, Ranks. Memory is interleaved for performance and thermal distribution.
If IMC Interleaving is set to 2-way, addresses will be interleaved between the two IMCs.
If IMC Interleaving is set to 1-way, there will be no interleaving.
If IMC Interleaving is set to auto, it depends on the SNC (Sub NUMA Clustering) setting, when SNC is set to enbaled, the IMC Interleaving will be 1-way interleave, SNC is set to disabled, the IMC Interleaving will be 2-way interleave.
If SNC is disabled, IMC Interleaving should be set to 2-way. If SNC is enabled, IMC Interleaving should be set to 1-way.
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. Default value is "disable"
SNC2: supports 2-way clustering. Utilizes LLC capacity efficiently and reduces latency due to core/IMC proximity. This may provide performance improvement on NUMA-aware operating systems.
SNC4: supports 4-way clustering. Utilizes LLC capacity more efficiently and reduces latency due to core/IMC proximity. This may provide performance improvement on NUMA-aware operating systems.
disable: supports 1-cluster and 2-way IMC interleave, the LLC is treated as one cluster.
In some Intel CPU caching schemes, mid-level cache (MLC) evictions are filled into the last level cache (LLC). If a line is evicted from the MLC to the LLC, the core can flag the evicted MLC lines as "dead". This means that the lines are not likely to be read again. This option allows dead lines to be dropped and never fill the LLC if the option is disabled.
Values for this BIOS option can be:
Disabled: Disabling this option can save space in the LLC by never filling MLC dead lines into the LLC.
Enabled: Opportunistically fill MLC dead lines in LLC, if space is available.
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:
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.
The Xtended Prediction Table (XPT) prefetcher exists on top of other prefetchers that can prefetch data into the DCU, MLC, and LLC. The XPT prefetcher will issue a speculative DRAM read request in parallel to an LLC lookup. This prefetch bypasses the LLC, saving latency. 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:
Enabled: Allows a read request sent to the LLC to speculatively issue a copy of the read to DRAM.
Disabled: Read requests to the LLC are not allowed to send a speculative read to DRAM.
The Active Cores allows you to choose how many Cores you want to enable for each CPU
Divide physical NUMA nodes into evenly sized virtual NUMA nodes in ACPI table. The default setting is Disabled.
Values for this BIOS option can be:
Enabled: Physical NUMA nodes will be devided into evenly sized virtual NUMA nodes.
Disabled: Physical NUMA nodes will not be devided into virtual NUMA nodes.