1. 09 Oct, 2009 1 commit
    • 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>
  2. 01 Oct, 2009 1 commit
  3. 24 Sep, 2009 2 commits
  4. 22 Sep, 2009 1 commit
    • Arjan van de Ven's avatar
      cpuidle: fix the menu governor to boost IO performance · 69d25870
      Arjan van de Ven authored
      Fix the menu idle governor which balances power savings, energy efficiency
      and performance impact.
      The reason for a reworked governor is that there have been serious
      performance issues reported with the existing code on Nehalem server
      To show this I'm sure Andrew wants to see benchmark results:
      (benchmark is "fio", "no cstates" is using "idle=poll")
      		no cstates	current linux	new algorithm
      1 disk		107 Mb/s	85 Mb/s		105 Mb/s
      2 disks		215 Mb/s	123 Mb/s	209 Mb/s
      12 disks	590 Mb/s	320 Mb/s	585 Mb/s
      In various power benchmark measurements, no degredation was found by our
      measurement&diagnostics team.  Obviously a small percentage more power was
      used in the "fio" benchmark, due to the much higher performance.
      While it would be a novel idea to describe the new algorithm in this
      commit message, I cheaped out and described it in comments in the code
      [changes since first post: spelling fixes from akpm, review feedback,
      folded menu-tng into menu.c]
      Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
      Cc: Len Brown <lenb@kernel.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
      Acked-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  5. 21 Sep, 2009 2 commits
    • Ingo Molnar's avatar
      perf: Do the big rename: Performance Counters -> Performance Events · cdd6c482
      Ingo Molnar authored
      Bye-bye Performance Counters, welcome Performance Events!
      In the past few months the perfcounters subsystem has grown out its
      initial role of counting hardware events, and has become (and is
      becoming) a much broader generic event enumeration, reporting, logging,
      monitoring, analysis facility.
      Naming its core object 'perf_counter' and naming the subsystem
      'perfcounters' has become more and more of a misnomer. With pending
      code like hw-breakpoints support the 'counter' name is less and
      less appropriate.
      All in one, we've decided to rename the subsystem to 'performance
      events' and to propagate this rename through all fields, variables
      and API names. (in an ABI compatible fashion)
      The word 'event' is also a bit shorter than 'counter' - which makes
      it slightly more convenient to write/handle as well.
      Thanks goes to Stephane Eranian who first observed this misnomer and
      suggested a rename.
      User-space tooling and ABI compatibility is not affected - this patch
      should be function-invariant. (Also, defconfigs were not touched to
      keep the size down.)
      This patch has been generated via the following script:
        FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')
        sed -i \
          -e 's/PERF_EVENT_/PERF_RECORD_/g' \
          -e 's/PERF_COUNTER/PERF_EVENT/g' \
          -e 's/perf_counter/perf_event/g' \
          -e 's/nb_counters/nb_events/g' \
          -e 's/swcounter/swevent/g' \
          -e 's/tpcounter_event/tp_event/g' \
        for N in $(find . -name perf_counter.[ch]); do
          M=$(echo $N | sed 's/perf_counter/perf_event/g')
          mv $N $M
        FILES=$(find . -name perf_event.*)
        sed -i \
          -e 's/COUNTER_MASK/REG_MASK/g' \
          -e 's/COUNTER/EVENT/g' \
          -e 's/\<event\>/event_id/g' \
          -e 's/counter/event/g' \
          -e 's/Counter/Event/g' \
      ... to keep it as correct as possible. This script can also be
      used by anyone who has pending perfcounters patches - it converts
      a Linux kernel tree over to the new naming. We tried to time this
      change to the point in time where the amount of pending patches
      is the smallest: the end of the merge window.
      Namespace clashes were fixed up in a preparatory patch - and some
      stylistic fallout will be fixed up in a subsequent patch.
      ( NOTE: 'counters' are still the proper terminology when we deal
        with hardware registers - and these sed scripts are a bit
        over-eager in renaming them. I've undone some of that, but
        in case there's something left where 'counter' would be
        better than 'event' we can undo that on an individual basis
        instead of touching an otherwise nicely automated patch. )
      Suggested-by: default avatarStephane Eranian <eranian@google.com>
      Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: default avatarPaul Mackerras <paulus@samba.org>
      Reviewed-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Kyle McMartin <kyle@mcmartin.ca>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: <linux-arch@vger.kernel.org>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    • Peter Williams's avatar
      sched: Simplify sys_sched_rr_get_interval() system call · 0d721cea
      Peter Williams authored
      By removing the need for it to know details of scheduling classes.
      This allows PlugSched to define orthogonal scheduling classes.
      Signed-off-by: default avatarPeter Williams <pwil3058@bigpond.net.au>
      Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Mike Galbraith <efault@gmx.de>
      LKML-Reference: <06d1b89ee15a0eef82d7.1253496713@mudlark.pw.nest>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  6. 20 Sep, 2009 2 commits
  7. 17 Sep, 2009 2 commits
    • Peter Zijlstra's avatar
      sched: Add new wakeup preemption mode: WAKEUP_RUNNING · ad4b78bb
      Peter Zijlstra authored
      Create a new wakeup preemption mode, preempt towards tasks that run
      shorter on avg. It sets next buddy to be sure we actually run the task
      we preempted for.
      Test results:
       root@twins:~# while :; do :; done &
       [1] 6537
       root@twins:~# while :; do :; done &
       [2] 6538
       root@twins:~# while :; do :; done &
       [3] 6539
       root@twins:~# while :; do :; done &
       [4] 6540
       root@twins:/home/peter# ./latt -c4 sleep 4
       Entries: 48 (clients=4)
              Max          4750 usec
              Avg           497 usec
              Stdev         737 usec
       root@twins:/home/peter# echo WAKEUP_RUNNING > /debug/sched_features
       root@twins:/home/peter# ./latt -c4 sleep 4
       Entries: 48 (clients=4)
              Max            14 usec
              Avg             5 usec
              Stdev           3 usec
      Disabled by default - needs more testing.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: default avatarMike Galbraith <efault@gmx.de>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      LKML-Reference: <new-submission>
    • Ingo Molnar's avatar
      sched: Fix TASK_WAKING & loadaverage breakage · eb24073b
      Ingo Molnar authored
      Fix this:
      top - 21:54:00 up  2:59,  1 user,  load average: 432512.33, 426421.74, 417432.74
      Which happens because we now set TASK_WAKING before activate_task().
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Mike Galbraith <efault@gmx.de>
      LKML-Reference: <new-submission>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  8. 16 Sep, 2009 1 commit
  9. 15 Sep, 2009 12 commits
  10. 04 Sep, 2009 10 commits
  11. 02 Sep, 2009 1 commit
    • Arjan van de Ven's avatar
      sched: Provide iowait counters · 8f0dfc34
      Arjan van de Ven authored
      For counting how long an application has been waiting for
      (disk) IO, there currently is only the HZ sample driven
      information available, while for all other counters in this
      class, a high resolution version is available via
      In order to make an improved bootchart tool possible, we also
      need a higher resolution version of the iowait time.
      This patch below adds this scheduler statistic to the kernel.
      Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      LKML-Reference: <4A64B813.1080506@linux.intel.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  12. 29 Aug, 2009 1 commit
  13. 28 Aug, 2009 1 commit
    • Peter Zijlstra's avatar
      sched: Fix division by zero - really · 34d76c41
      Peter Zijlstra authored
      When re-computing the shares for each task group's cpu
      representation we need the ratio of weight on each cpu vs the
      total weight of the sched domain.
      Since load-balancing is loosely (read not) synchronized, the
      weight of individual cpus can change between doing the sum and
      calculating the ratio.
      The previous patch dealt with only one of the race scenarios,
      this patch side steps them all by saving a snapshot of all the
      individual cpu weights, thereby always working on a consistent
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: torvalds@linux-foundation.org
      Cc: jes@sgi.com
      Cc: jens.axboe@oracle.com
      Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
      Cc: Arjan van de Ven <arjan@infradead.org>
      Cc: Yinghai Lu <yinghai@kernel.org>
      LKML-Reference: <1251371336.18584.77.camel@twins>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  14. 23 Aug, 2009 1 commit
    • Paul E. McKenney's avatar
      rcu: Renamings to increase RCU clarity · d6714c22
      Paul E. McKenney authored
      Make RCU-sched, RCU-bh, and RCU-preempt be underlying
      implementations, with "RCU" defined in terms of one of the
      three.  Update the outdated rcu_qsctr_inc() names, as these
      functions no longer increment anything.
      Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: laijs@cn.fujitsu.com
      Cc: dipankar@in.ibm.com
      Cc: akpm@linux-foundation.org
      Cc: mathieu.desnoyers@polymtl.ca
      Cc: josht@linux.vnet.ibm.com
      Cc: dvhltc@us.ibm.com
      Cc: niv@us.ibm.com
      Cc: peterz@infradead.org
      Cc: rostedt@goodmis.org
      LKML-Reference: <12509746132696-git-send-email->
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  15. 21 Aug, 2009 1 commit
  16. 20 Aug, 2009 1 commit