SPEC CPU2017 Platform Settings for New_H3C AMD-based Systems

Operating System Tuning Parameters

sched_cfs_bandwidth_slice_us

This OS setting controls the amount of run-time(bandwidth) transferred to a run queue from the task's control group bandwidth pool. Small values allow the global bandwidth to be shared in a fine-grained manner among tasks, larger values reduce transfer overhead. The default value is 5000 (ns).

sched_latency_ns

This OS setting configures targeted preemption latency for CPU bound tasks. The default value is 24000000 (ns).

sched_migration_cost_ns

Amount of time after the last execution that a task is considered to be "cache hot" in migration decisions. A "hot" task is less likely to be migrated to another CPU, so increasing this variable reduces task migrations. The default value is 500000 (ns).

sched_min_granularity_ns

This OS setting controls the minimal preemption granularity for CPU bound tasks. As the number of runnable tasks increases, CFS(Complete Fair Scheduler), the scheduler of the Linux kernel, decreases the timeslices of tasks. If the number of runnable tasks exceeds sched_latency_ns/sched_min_granularity_ns, the timeslice becomes number_of_running_tasks * sched_min_granularity_ns. The default value is 8000000 (ns).

sched_wakeup_granularity_ns

This OS setting controls the wake-up preemption granularity. Increasing this variable reduces wake-up preemption, reducing disturbance of compute bound tasks. Lowering it improves wake-up latency and throughput for latency critical tasks, particularly when a short duty cycle load component must compete with CPU bound components. The default value is 10000000 (ns).

numa_balancing

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

Firmware / BIOS / Microcode Settings

Set Operating Mode: (Default="Maximum Efficiency")

Select the operating mode based on your preference. Note, power savings and performance are also highly dependent on hardware and software running on system.

• "Maximum Efficiency" 'Efficiency' balances performance and power consumption.
• "Maximum Performance"'Performance' maxmizes performance minimizes latency with little regard to power consumption.

Determinism Slider: (Default="Auto"):

This option allows the user to choose between an Auto and Manual mode for Determinism Control. Values for this BIOS option can be.

• "Auto": The system will decide what Performance Determinism setting to use. Auto also uses the processor fused values for Determinism.
• "Manual": Allows the user to select either Power Deterministic or Performance Deterministic.

Global C-states Control: (Default="Disabled"):

Controls IO based C-state generation and DF C-states.Values for this BIOS setting can be.

• Enabled
• Disabled
• Auto

cTDP Control: (Default="Auto"):

Auto = Use the fused cTDP Manual = User can set customized cTDP.

• Auto:Use the fused cTDP Manual = User can set customized cTDP.
• Manual

cTDP:

cTDP is the acronym for Configurable TDP. Some Rome CPU skus support a default TDP and a higher cTDP expressed in Watts. Model Normal TDP Minimum cTDP Maximum cTDP EPYC 7H12 280 225 280 EPYC 7742 225 225 240 EPYC 7702 200 165 200 EPYC 7702P 200 165 200 EPYC 7662 225 225 240 EPYC 7642 225 225 240 EPYC 7502 180 165 200 EPYC 7502P 180 165 200 EPYC 7542 225 225 240 EPYC 7402 180 165 200 EPYC 7402P 180 165 200 EPYC 7302 155 155 180 EPYC 7302P 155 155 180 EPYC 7252 120 120 150

NUMA nodes per socket: (Default="Auto"):

Specifies the number of desired NUMA nodes per socket. Zero will attempt to interleave the two sockets together.

• Auto
• NPS4:"NPS4" sets four NUMA nodes per socket, one per Quadrant.
• NPS2:"NPS2" sets two NUMA nodes per socket.
• NPS1:"NPS1" sets one NUMA nodes per socket.
• NPS0

APBDIS: (Default="Auto"):

Values for this BIOS setting can be.

• Auto
• 0:Dynamically switch Infinity Fabric P-state based on link usage.
• 1:Enable fixed Infinity Fabric P-state control.

Soc P-States: (Default="P0"):

Values for this BIOS setting can be.

• P0:Highest-performing Infinity Fabric P-state,which will force the Infinity Fabric and memory controllers into full-power mode.
• P1:Next-highest-performing Infinity Fabric P-state.
• P2:Next highest-performing Infinity Fabric P-state.
• P3:Minimum Infinity Fabric power P-state.

Package Power Limit Control: (Default="Auto"):

This is a per Processor Power Limit value applicable for all populated processors in the system. This can be set to limit the processor power to a certain value. Values for this BIOS option can be.

• Auto: Uses the default processor value.
• Manual: Lets the user set a power limit and exposes Package Power Limit value field that a user can enter a number into. If a number is entered higher than what the processor and/or system supports, the BIOS will limit the power to the max possible value.

Memory Speed:

Select the desired memory speed. Faster speeds offer better performance but consume more power.