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| author | Valdis Kletnieks <valdis.kletnieks@vt.edu> | 2006-04-19 09:23:09 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@nelson.home.kernel.dk> | 2006-04-20 13:04:36 +0200 |
| commit | 73af994c7d58dd513922dc9d5cd76b124ec02b1b (patch) | |
| tree | 793dfd57372a73a5c4b1e7c8b9f33a04fc08b61e /Documentation/block | |
| parent | 5a7b46b369419493bab4de67b1526e9f76b22a7f (diff) | |
| download | lwn-73af994c7d58dd513922dc9d5cd76b124ec02b1b.tar.gz lwn-73af994c7d58dd513922dc9d5cd76b124ec02b1b.zip | |
[PATCH] Document online io scheduler switching
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>
Diffstat (limited to 'Documentation/block')
| -rw-r--r-- | Documentation/block/switching-sched.txt | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/block/switching-sched.txt b/Documentation/block/switching-sched.txt new file mode 100644 index 000000000000..5fa130a67531 --- /dev/null +++ b/Documentation/block/switching-sched.txt @@ -0,0 +1,22 @@ +As of the Linux 2.6.10 kernel, it is now possible to change the +IO scheduler for a given block device on the fly (thus making it possible, +for instance, to set the CFQ scheduler for the system default, but +set a specific device to use the anticipatory or noop schedulers - which +can improve that device's throughput). + +To set a specific scheduler, simply do this: + +echo SCHEDNAME > /sys/block/DEV/queue/scheduler + +where SCHEDNAME is the name of a defined IO scheduler, and DEV is the +device name (hda, hdb, sga, or whatever you happen to have). + +The list of defined schedulers can be found by simply doing +a "cat /sys/block/DEV/queue/scheduler" - the list of valid names +will be displayed, with the currently selected scheduler in brackets: + +# cat /sys/block/hda/queue/scheduler +noop anticipatory deadline [cfq] +# echo anticipatory > /sys/block/hda/queue/scheduler +# cat /sys/block/hda/queue/scheduler +noop [anticipatory] deadline cfq |