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authorIngo Molnar <mingo@kernel.org>2013-12-17 15:22:35 +0100
committerIngo Molnar <mingo@kernel.org>2013-12-17 15:22:35 +0100
commitffe732c2430c55074bebb172d33d909c662cd0e3 (patch)
treed39087d7b5d8caa505b23b6ea2abc2e33efa5be5 /tools/power/cpupower/man/cpupower-idle-set.1
parent40ea2b42d7c44386cf81d5636d574193da2c8df2 (diff)
parent757dfcaa41844595964f1220f1d33182dae49976 (diff)
downloadblackbird-op-linux-ffe732c2430c55074bebb172d33d909c662cd0e3.tar.gz
blackbird-op-linux-ffe732c2430c55074bebb172d33d909c662cd0e3.zip
Merge branch 'sched/urgent' into sched/core
Merge the latest batch of fixes before applying development patches. Signed-off-by: Ingo Molnar <mingo@kernel.org>
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+.TH "CPUPOWER-IDLE-SET" "1" "0.1" "" "cpupower Manual"
+.SH "NAME"
+.LP
+cpupower idle\-set \- Utility to set cpu idle state specific kernel options
+.SH "SYNTAX"
+.LP
+cpupower [ \-c cpulist ] idle\-info [\fIoptions\fP]
+.SH "DESCRIPTION"
+.LP
+The cpupower idle\-set subcommand allows to set cpu idle, also called cpu
+sleep state, specific options offered by the kernel. One example is disabling
+sleep states. This can be handy for power vs performance tuning.
+.SH "OPTIONS"
+.LP
+.TP
+\fB\-d\fR \fB\-\-disable\fR
+Disable a specific processor sleep state.
+.TP
+\fB\-e\fR \fB\-\-enable\fR
+Enable a specific processor sleep state.
+
+.SH "REMARKS"
+.LP
+Cpuidle Governors Policy on Disabling Sleep States
+
+.RS 4
+Depending on the used cpuidle governor, implementing the kernel policy
+how to choose sleep states, subsequent sleep states on this core, might get
+disabled as well.
+
+There are two cpuidle governors ladder and menu. While the ladder
+governor is always available, if CONFIG_CPU_IDLE is selected, the
+menu governor additionally requires CONFIG_NO_HZ.
+
+The behavior and the effect of the disable variable depends on the
+implementation of a particular governor. In the ladder governor, for
+example, it is not coherent, i.e. if one is disabling a light state,
+then all deeper states are disabled as well. Likewise, if one enables a
+deep state but a lighter state still is disabled, then this has no effect.
+.RE
+.LP
+Disabling the Lightest Sleep State may not have any Affect
+
+.RS 4
+If criteria are not met to enter deeper sleep states and the lightest sleep
+state is chosen when idle, the kernel may still enter this sleep state,
+irrespective of whether it is disabled or not. This is also reflected in
+the usage count of the disabled sleep state when using the cpupower idle-info
+command.
+.RE
+.LP
+Selecting specific CPU Cores
+
+.RS 4
+By default processor sleep states of all CPU cores are set. Please refer
+to the cpupower(1) manpage in the \-\-cpu option section how to disable
+C-states of specific cores.
+.RE
+.SH "FILES"
+.nf
+\fI/sys/devices/system/cpu/cpu*/cpuidle/state*\fP
+\fI/sys/devices/system/cpu/cpuidle/*\fP
+.fi
+.SH "AUTHORS"
+.nf
+Thomas Renninger <trenn@suse.de>
+.fi
+.SH "SEE ALSO"
+.LP
+cpupower(1), cpupower\-monitor(1), cpupower\-info(1), cpupower\-set(1),
+cpupower\-idle\-info(1)
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