CPU2017 Flag Description - Platform settings for New H3C systems

Operating System Tuning Parameters

cpupower

Manage the frequency scaling of your CPU.We use "cpupower frequency-set -g performance" to set to performance mode.

• performance: Run the CPU at the maximum frequency.
• powersave(default): Run the CPU at the minimum frequency.

tuned-adm

Tuning profile delivery mechanism for Linux.We use "tuned-adm profile throughput-performance" to set to throughput-performance profile.

• accelerator-performance: Throughput-performance based tuning with disabled higher latency STOP states.
• balanced: General non-specialized tuned profile.
• desktop: Optimize for the desktop use-case.
• hpc-compute: Optimize for HPC compute workloads.
• intel-sst: Configure for Intel Speed Select Base Frequency.
• latency-performance: Optimize for deterministic performance at the cost of increased power consumption.
• network-latency: Optimize for deterministic performance at the cost of increased power consumption, focused on low latency network performance.
• network-throughput: Optimize for streaming network throughput, generally only necessary on older CPUs or 40G+ networks.
• optimize-serial-console: Optimize for serial console use.
• powersave: Optimize for low power consumption.
• throughput-performance(default): Broadly applicable tuning that provides excellent performance across a variety of common server workloads.
• virtual-guest: Optimize for running inside a virtual guest.
• virtual-host: Optimize for running KVM guests.

Firmware / BIOS / Microcode Settings

Enable LP [Global]

Select whether all logical processors are enabled.

• ALL LPs(Default Setting):Enable all logical processors.
• Single LP:Enable only a single logical processor.

Package C State

Package C state is one of energy saving options of the processor, which not only allow the individual cores of a processor, but the entire processor chip to be put into a type of sleep state. As a result, power consumption is even further reduced. But the waking up time that is required to change from the lower package C state to the active state is even longer in comparison with the CPU core C state. The higher the package C state, the lower the power usage of that idle package state. If the "C0/C1" is set, the processor chip always remains active, and it can improve the performance of latency sensitive workloads.

• C0/C1 state(Default Setting):When the CPU is idle, the system slightly reduces power consumption. This option requires less power than C0 and allows the server to return quickly to high-performance mode.
• C2 state:When the CPU is idle, the system reduces power consumption more than with the C1 option. This option requires less power than C1 or C0, but the server takes slightly longer to return to high-performance mode.
• C6(non Retention) state:When the CPU is idle, the system reduces power consumption more than with the C3 option. This option saves more power than C0, C1, or C3, but the system may experience performance problems until the server returns to full power.
• C6(Retention) state:When the CPU is idle, the system reduces power consumption more than with the C3 option. This option consumes slightly more power than the C6 Nonretention option, because the processor is operating at Pn voltage to reduce the package’s C-state exit latency.
• No Limit:all C-States supported by the processor are available.
• Auto:Initialize to deepest available package C state limit.

SNC

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.

• Auto:decides based on Si Compatibility.
• Disabled(Default Setting):supports 1-cluster and 2-way IMC interleave, the LLC is treated as one cluster.
• Enable SNC2 (2-clusters):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.

Intel VT for Directed I/O

This BIOS option enables or disables I/O virtualization functions of the CPU.If the server is not used for virtualization, this option should be set to "Disabled".Default setting is "Enabled".

VMX

This BIOS option enables or disables additional virtualization functions of the CPU.If the server is not used for virtualization, this option should be set to "Disabled".This can result in energy savings. Default setting is "Enabled".

LLC Prefetch

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).

• Disabled(Default Setting):not allowed to prefetch data into the core data cache unit and L2 cache.
• Enabled: Enabling LLC prefetch gives the core prefetcher the ability to prefetch data directly into the LLC

CPU C6 Report

Enable or disable reporting of the CPU C6 State (ACPI C3) to the OS. During the CPU C6 State, the power to all cache is turned off.The default is "Disabled".

Virtual NUMA

Divide physical NUMA nodes into evenly sized virtual NUMA nodes in ACPI table.

• Disabled(Default Setting):Physical NUMA nodes will not be devided into virtual NUMA nodes.
• Enabled:Physical NUMA nodes will be devided into evenly sized virtual NUMA nodes.

Fan mode:

To Select system Fan policy on BMC WebUI.

• Balanced mode(Default Setting): : makes fan speed self-adjust actively according to the reading of the system temperature sensors.
• Silent mode : makes fan speed self-adjust actively according to the reading of the system temperature sensors.but fan speed is lower and quieter when the server is under low load.
• powerful mode: makes fan run at full speed to provide best cooling performance.
• Custom mode: allow users to customize fan speed settings.