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+===================
+Switching Scheduler
+===================
+
+To choose IO schedulers at boot time, use the argument 'elevator=deadline'.
+'noop' 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
+
+It is possible to change the IO scheduler for a given block device on
+the fly to select one of mq-deadline, none, bfq, or kyber 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/sda/queue/scheduler
+  [mq-deadline] kyber bfq none
+  # echo none >/sys/block/sda/queue/scheduler
+  # cat /sys/block/sda/queue/scheduler
+  [none] mq-deadline kyber bfq