Manual: cpupower-set

CPUPOWER-SET(1)					       cpupower Manual					     CPUPOWER-SET(1)

NAME
       cpupower-set - Set processor power related kernel or hardware configurations

SYNOPSIS
       cpupower set [ -b VAL | -e POLICY | -m MODE | -t BOOL ]

DESCRIPTION
       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) manpage in the --cpu option section. Whether an option af‐
       fects 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 system at all.

OPTIONS
       --perf-bias, -b
	   Sets	 a register on supported Intel processore which allows software to convey its policy for the relative impor‐
	   tance of performance versus energy savings to the  processor.

	   The range of valid numbers is 0-15, where 0 is maximum performance and 15 is maximum energy efficiency.

	   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 frequency range.  It may also tell the hardware how	 ag‐
	   gressively it should enter the OS requested C-states.

	   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.

       --epp, -e
	   Sets the energy performance policy preference on supported Intel or AMD processors which use the Intel or AMD  P-
	   State cpufreq driver respectively.

	   Available  policies	can  be	 found	with  cat  /sys/devices/system/cpu/cpufreq/policy0/energy_performance_avail‐
	   able_preferences :
	       default performance balance_performance balance_power power

       --amd-pstate-mode, -m
	   Sets the AMD P-State mode for supported AMD processors.  Available modes are "active", "guided" or "passive".

	   Refer to the AMD P-State kernel documentation for further information.

       --turbo-boost, --boost, -t
	   This option is used to enable or disable the boost feature on supported Intel and AMD processors, and other boost
	   supported systems.  (The --boost option is an alias for the --turbo-boost option)

	   This option takes as parameter either 1 to enable, or 0 to disable the feature.

SEE ALSO
       cpupower-info(1), cpupower-monitor(1), powertop(1)

AUTHORS
       --perf-bias parts written by Len Brown 
       Thomas Renninger 

							 22/02/2011					     CPUPOWER-SET(1)