1 =================== 2 Switching Scheduler 3 =================== 4 5 Each io queue has a set of io scheduler tunables associated with it. These 6 tunables control how the io scheduler works. You can find these entries 7 in:: 8 9 /sys/block/<device>/queue/iosched 10 11 assuming that you have sysfs mounted on /sys. If you don't have sysfs mounted, 12 you can do so by typing:: 13 14 # mount none /sys -t sysfs 15 16 It is possible to change the IO scheduler for a given block device on 17 the fly to select one of mq-deadline, none, bfq, or kyber schedulers - 18 which can improve that device's throughput. 19 20 To set a specific scheduler, simply do this:: 21 22 echo SCHEDNAME > /sys/block/DEV/queue/scheduler 23 24 where SCHEDNAME is the name of a defined IO scheduler, and DEV is the 25 device name (hda, hdb, sga, or whatever you happen to have). 26 27 The list of defined schedulers can be found by simply doing 28 a "cat /sys/block/DEV/queue/scheduler" - the list of valid names 29 will be displayed, with the currently selected scheduler in brackets:: 30 31 # cat /sys/block/sda/queue/scheduler 32 [mq-deadline] kyber bfq none 33 # echo none >/sys/block/sda/queue/scheduler 34 # cat /sys/block/sda/queue/scheduler 35 [none] mq-deadline kyber bfq
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