CentOS 7.0 - man page for cpupower-set (centos section 1)
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CPUPOWER-SET(1) cpupower Manual CPUPOWER-SET(1)
cpupower-set - Set processor power related kernel or hardware configurations
cpupower set [ -b VAL ] [ -s VAL ] [ -m VAL ]
cpupower set sets kernel configurations or directly accesses hardware registers affecting
processor power saving policies.
Some options are platform wide, some affect single cores. By default values are applied on
all cores. How to modify single core configurations is described in the cpupower(1) man-
page in the --cpu option section. Whether an option affects the whole system or can be
applied to individual cores is described in the Options sections.
Use cpupower info to read out current settings and whether they are supported on the sys-
tem at all.
Sets a register on supported Intel processore which allows software to convey its pol-
icy for the relative importance of performance versus energy savings to the proces-
The range of valid numbers is 0-15, where 0 is maximum performance and 15 is maximum
The processor uses this information in model-specific ways when it must select trade-
offs between performance and energy efficiency.
This policy hint does not supersede Processor Performance states (P-states) or CPU
Idle power states (C-states), but allows software to have influence where it would
otherwise be unable to express a preference.
For example, this setting may tell the hardware how aggressively or conservatively to
control frequency in the "turbo range" above the explicitly OS-controlled P-state fre-
quency range. It may also tell the hardware how aggressively it should enter the OS
This option can be applied to individual cores only via the --cpu option, cpupower(1).
Setting the performance bias value on one CPU can modify the setting on related CPUs
as well (for example all CPUs on one socket), because of hardware restrictions. Use
cpupower -c all info -b to verify.
This options needs the msr kernel driver (CONFIG_X86_MSR) loaded.
--sched-mc, -m [ VAL ]
--sched-smt, -s [ VAL ]
--sched-mc utilizes cores in one processor package/socket first before processes are
scheduled to other processor packages/sockets.
--sched-smt utilizes thread siblings of one processor core first before processes are
scheduled to other cores.
The impact on power consumption and performance (positiv or negativ) heavily depends
on processor support for deep sleep states, frequency scaling and frequency boost
modes and their dependencies between other thread siblings and processor cores.
Taken over from kernel documentation:
Adjust the kernel's multi-core scheduler support.
Possible values are:
0 - No power saving load balance (default value)
1 - Fill one thread/core/package first for long running threads
2 - Also bias task wakeups to semi-idle cpu package for power savings
cpupower-info(1), cpupower-monitor(1), powertop(1)
--perf-bias parts written by Len Brown <firstname.lastname@example.org>
Thomas Renninger <email@example.com>
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