| Thomas Renninger | 5094d27 | 2013-11-16 14:39:21 +0100 | [diff] [blame^] | 1 | .TH "CPUPOWER-IDLE-SET" "1" "0.1" "" "cpupower Manual" |
| 2 | .SH "NAME" |
| 3 | .LP |
| 4 | cpupower idle\-set \- Utility to set cpu idle state specific kernel options |
| 5 | .SH "SYNTAX" |
| 6 | .LP |
| 7 | cpupower [ \-c cpulist ] idle\-info [\fIoptions\fP] |
| 8 | .SH "DESCRIPTION" |
| 9 | .LP |
| 10 | The cpupower idle\-set subcommand allows to set cpu idle, also called cpu |
| 11 | sleep state, specific options offered by the kernel. One example is disabling |
| 12 | sleep states. This can be handy for power vs performance tuning. |
| 13 | .SH "OPTIONS" |
| 14 | .LP |
| 15 | .TP |
| 16 | \fB\-d\fR \fB\-\-disable\fR |
| 17 | Disable a specific processor sleep state. |
| 18 | .TP |
| 19 | \fB\-e\fR \fB\-\-enable\fR |
| 20 | Enable a specific processor sleep state. |
| 21 | |
| 22 | .SH "REMARKS" |
| 23 | .LP |
| 24 | Cpuidle Governors Policy on Disabling Sleep States |
| 25 | |
| 26 | .RS 4 |
| 27 | Depending on the used cpuidle governor, implementing the kernel policy |
| 28 | how to choose sleep states, subsequent sleep states on this core, might get |
| 29 | disabled as well. |
| 30 | |
| 31 | There are two cpuidle governors ladder and menu. While the ladder |
| 32 | governor is always available, if CONFIG_CPU_IDLE is selected, the |
| 33 | menu governor additionally requires CONFIG_NO_HZ. |
| 34 | |
| 35 | The behavior and the effect of the disable variable depends on the |
| 36 | implementation of a particular governor. In the ladder governor, for |
| 37 | example, it is not coherent, i.e. if one is disabling a light state, |
| 38 | then all deeper states are disabled as well. Likewise, if one enables a |
| 39 | deep state but a lighter state still is disabled, then this has no effect. |
| 40 | .RE |
| 41 | .LP |
| 42 | Disabling the Lightest Sleep State may not have any Affect |
| 43 | |
| 44 | .RS 4 |
| 45 | If criteria are not met to enter deeper sleep states and the lightest sleep |
| 46 | state is chosen when idle, the kernel may still enter this sleep state, |
| 47 | irrespective of whether it is disabled or not. This is also reflected in |
| 48 | the usage count of the disabled sleep state when using the cpupower idle-info |
| 49 | command. |
| 50 | .RE |
| 51 | .LP |
| 52 | Selecting specific CPU Cores |
| 53 | |
| 54 | .RS 4 |
| 55 | By default processor sleep states of all CPU cores are set. Please refer |
| 56 | to the cpupower(1) manpage in the \-\-cpu option section how to disable |
| 57 | C-states of specific cores. |
| 58 | .RE |
| 59 | .SH "FILES" |
| 60 | .nf |
| 61 | \fI/sys/devices/system/cpu/cpu*/cpuidle/state*\fP |
| 62 | \fI/sys/devices/system/cpu/cpuidle/*\fP |
| 63 | .fi |
| 64 | .SH "AUTHORS" |
| 65 | .nf |
| 66 | Thomas Renninger <trenn@suse.de> |
| 67 | .fi |
| 68 | .SH "SEE ALSO" |
| 69 | .LP |
| 70 | cpupower(1), cpupower\-monitor(1), cpupower\-info(1), cpupower\-set(1), |
| 71 | cpupower\-idle\-info(1) |