diff options
| author | Alan D. Brunelle <Alan.Brunelle@hp.com> | 2007-10-15 13:22:26 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2007-10-16 09:59:55 +0200 |
| commit | 23c76983e23628c7762137a00651e3e371aa97d3 (patch) | |
| tree | 3e335f0eb806b7890542420d6c2f635823d210ff /Documentation/block/switching-sched.txt | |
| parent | 26bbb29a2a4e1491238ae49bf3294955dc0ab662 (diff) | |
| download | lwn-23c76983e23628c7762137a00651e3e371aa97d3.tar.gz lwn-23c76983e23628c7762137a00651e3e371aa97d3.zip | |
Some IO scheduler cleanup in Documentation/block
as-iosched.txt:
o Changed IO scheduler selection text to a reference to the
switching-sched.txt file.
o Fixed typo: 'for up time...' -> 'for up to...'
o Added short description of the est_time file.
deadline-iosched.txt:
o Changed IO scheduler selection text to a reference to the
switching-sched.txt file.
o Removed references to non-existent seek-cost and stream_unit.
o Fixed typo: 'write_starved' -> 'writes_starved'
switching-sched.txt:
o Added in boot-time argument to set the default IO scheduler. (From
as-iosched.txt)
o Added in sysfs mount instructions. (From deadline-iosched.txt)
Signed-off-by: Alan D. Brunelle <Alan.Brunelle@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'Documentation/block/switching-sched.txt')
| -rw-r--r-- | Documentation/block/switching-sched.txt | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/block/switching-sched.txt b/Documentation/block/switching-sched.txt index 5fa130a67531..634c952e1964 100644 --- a/Documentation/block/switching-sched.txt +++ b/Documentation/block/switching-sched.txt @@ -1,3 +1,18 @@ +To choose IO schedulers at boot time, use the argument 'elevator=deadline'. +'noop', 'as' and 'cfq' (the default) are also available. IO schedulers are +assigned globally at boot time only presently. + +Each io queue has a set of io scheduler tunables associated with it. These +tunables control how the io scheduler works. You can find these entries +in: + +/sys/block/<device>/queue/iosched + +assuming that you have sysfs mounted on /sys. If you don't have sysfs mounted, +you can do so by typing: + +# mount none /sys -t sysfs + 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 @@ -20,3 +35,9 @@ noop anticipatory deadline [cfq] # echo anticipatory > /sys/block/hda/queue/scheduler # cat /sys/block/hda/queue/scheduler noop [anticipatory] deadline cfq + +Each io queue has a set of io scheduler tunables associated with it. These +tunables control how the io scheduler works. You can find these entries +in: + +/sys/block/<device>/queue/iosched |