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  1. 28 Oct, 2009 1 commit
    • Corrado Zoccolo's avatar
      cfq-iosched: adapt slice to number of processes doing I/O · 5db5d642
      Corrado Zoccolo authored 
      When the number of processes performing I/O concurrently increases,
a fixed time slice per process will cause large latencies.

This patch, if low_latency mode is enabled,  will scale the time slice
assigned to each process according to a 300ms target latency.

In order to keep fairness among processes:
* The number of active processes is computed using a special form of
running average, that quickly follows sudden increases (to keep latency low),
and decrease slowly (to have fairness in spite of rapid decreases of this
value).

To safeguard sequential bandwidth, we impose a minimum time slice
(computed using 2*cfq_slice_idle as base, adjusted according to priority
and async-ness).
Signed-off-by: default avatarCorrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      5db5d642
  3. 27 Oct, 2009 1 commit
  5. 26 Oct, 2009 4 commits
  7. 13 Oct, 2009 3 commits
  9. 12 Oct, 2009 1 commit
  11. 09 Oct, 2009 3 commits
    • Wu Fengguang's avatar
      writeback: kill space in debugfs item name · 961515f6
      Wu Fengguang authored 
      The space is not script friendly, kill it.
Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      961515f6
    • Wu Fengguang's avatar
      writeback: account IO throttling wait as iowait · d25105e8
      Wu Fengguang authored 
      It makes sense to do IOWAIT when someone is blocked
due to IO throttle, as suggested by Kame and Peter.

There is an old comment for not doing IOWAIT on throttle,
however it has been mismatching the code for a long time.

If we stop accounting IOWAIT for 2.6.32, it could be an
undesirable behavior change. So restore the io_schedule.

CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      d25105e8
    • KOSAKI Motohiro's avatar
      elv_iosched_store(): fix strstrip() misuse · 8c279598
      KOSAKI Motohiro authored 
      elv_iosched_store() ignore the return value of strstrip().  It makes small
inconsistent behavior.

This patch fixes it.

 <before>
 ====================================
 # cd /sys/block/{blockdev}/queue

 case1:
 # echo "anticipatory" > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case2:
 # echo "anticipatory " > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case3:
 # echo " anticipatory" > scheduler
 bash: echo: write error: Invalid argument

 <after>
 ====================================
 # cd /sys/block/{blockdev}/queue

 case1:
 # echo "anticipatory" > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case2:
 # echo "anticipatory " > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case3:
 # echo " anticipatory" > scheduler
 noop [anticipatory] deadline cfq

Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      8c279598
  13. 08 Oct, 2009 1 commit
  15. 07 Oct, 2009 3 commits
  17. 06 Oct, 2009 5 commits
  19. 05 Oct, 2009 6 commits
  21. 04 Oct, 2009 12 commits