73af994c7d
We added the ability to change a block device's IO elevator scheduler both at kernel boot and on-the-fly, but we only documented the elevator= boot parameter. Add a quick how-to on doing it on the fly. Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Jens Axboe <axboe@suse.de>
22 lines
935 B
Text
22 lines
935 B
Text
As of the Linux 2.6.10 kernel, it is now possible to change the
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IO scheduler for a given block device on the fly (thus making it possible,
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for instance, to set the CFQ scheduler for the system default, but
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set a specific device to use the anticipatory or noop schedulers - which
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can improve that device's throughput).
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To set a specific scheduler, simply do this:
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echo SCHEDNAME > /sys/block/DEV/queue/scheduler
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where SCHEDNAME is the name of a defined IO scheduler, and DEV is the
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device name (hda, hdb, sga, or whatever you happen to have).
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The list of defined schedulers can be found by simply doing
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a "cat /sys/block/DEV/queue/scheduler" - the list of valid names
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will be displayed, with the currently selected scheduler in brackets:
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# cat /sys/block/hda/queue/scheduler
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noop anticipatory deadline [cfq]
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# echo anticipatory > /sys/block/hda/queue/scheduler
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# cat /sys/block/hda/queue/scheduler
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noop [anticipatory] deadline cfq
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