SPEC CPU2006 Platform Settings for SGI UV 3000 Intel-based systems
- dplace -c cpulist -r bB $command
- dplace is a tool for binding processes to cpus
Here is a brief description of options used in the config file:
- -c cpulist: pin processes to the specified comma-separated list or range of cpus. These are logical cpus, relative to the enclosing cpuset.
- -r bB: specifies that text should be replicated on the NUMA node or nodes where the process is running. 'b' indicates that the binary (a.out) text should be replicated and 'B' indicates that the binary (a.out) read/write data should be replicated.
- For full details on using dplace, please refer to your Linux documentation, 'man dplace'.
- Transparent Huge Pages
- On SLES11 SP2 and later, 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.
Hugepages are used by default unless the /sys/kernel/mm/transparent_hugepage/enabled field is changed from its default of 'always' to 'never' or 'madvise'.
- sysctl vm.stat_interval = value
- This sets the time interval (in seconds) between updates of virtual memory statistics, such as the number of free pages per NUMA node; the default interval is 1 second. Increasing this value may reduce contention for vmstat cachelines in the kernel, thereby reducing system overhead.
- 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.
- cpupower frequency-set -d [min_freq] -u [max_freq] -g [governor]
- "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".
- -d [min_freq]: new minimum CPU frequency the governor may select.
- -u [max_freq]: new maximum CPU frequency the governor may select.
- -g [governor]: new cpufreq governor. The performance governor will run the processor at the max_freq setting.
- BT Mode: (Default = "Force mode 0")
-
The BT mode controls relative allocations of processor/QPI-related resources.
UV 300 supports two modes of operation for the BT:
- "Force mode 0" optimizes for global memory references (best for non-NUMA-aware applications).
- "Auto-select" optimizes for local memory references (best for NUMA-aware applications).