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| 1 | As of the Linux 2.6.10 kernel, it is now possible to change the | ||
| 2 | IO scheduler for a given block device on the fly (thus making it possible, | ||
| 3 | for instance, to set the CFQ scheduler for the system default, but | ||
| 4 | set a specific device to use the anticipatory or noop schedulers - which | ||
| 5 | can improve that device's throughput). | ||
| 6 | |||
| 7 | To set a specific scheduler, simply do this: | ||
| 8 | |||
| 9 | echo SCHEDNAME > /sys/block/DEV/queue/scheduler | ||
| 10 | |||
| 11 | where SCHEDNAME is the name of a defined IO scheduler, and DEV is the | ||
| 12 | device name (hda, hdb, sga, or whatever you happen to have). | ||
| 13 | |||
| 14 | The list of defined schedulers can be found by simply doing | ||
| 15 | a "cat /sys/block/DEV/queue/scheduler" - the list of valid names | ||
| 16 | will be displayed, with the currently selected scheduler in brackets: | ||
| 17 | |||
| 18 | # cat /sys/block/hda/queue/scheduler | ||
| 19 | noop anticipatory deadline [cfq] | ||
| 20 | # echo anticipatory > /sys/block/hda/queue/scheduler | ||
| 21 | # cat /sys/block/hda/queue/scheduler | ||
| 22 | noop [anticipatory] deadline cfq | ||
