1. 11 Feb, 2009 2 commits
  2. 06 Feb, 2009 2 commits
  3. 05 Feb, 2009 4 commits
    • Peter Zijlstra's avatar
      timers: split process wide cpu clocks/timers · 4cd4c1b4
      Peter Zijlstra authored
      Change the process wide cpu timers/clocks so that we:
      
       1) don't mess up the kernel with too many threads,
       2) don't have a per-cpu allocation for each process,
       3) have no impact when not used.
      
      In order to accomplish this we're going to split it into two parts:
      
       - clocks; which can take all the time they want since they run
                 from user context -- ie. sys_clock_gettime(CLOCK_PROCESS_CPUTIME_ID)
      
       - timers; which need constant time sampling but since they're
                 explicity used, the user can pay the overhead.
      
      The clock readout will go back to a full sum of the thread group, while the
      timers will run of a global 'clock' that only runs when needed, so only
      programs that make use of the facility pay the price.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Reviewed-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      4cd4c1b4
    • Peter Zijlstra's avatar
      signal: re-add dead task accumulation stats. · 32bd671d
      Peter Zijlstra authored
      We're going to split the process wide cpu accounting into two parts:
      
       - clocks; which can take all the time they want since they run
                 from user context.
      
       - timers; which need constant time tracing but can affort the overhead
                 because they're default off -- and rare.
      
      The clock readout will go back to a full sum of the thread group, for this
      we need to re-add the exit stats that were removed in the initial itimer
      rework (f06febc9: timers: fix itimer/many thread hang).
      
      Furthermore, since that full sum can be rather slow for large thread groups
      and we have the complete dead task stats, revert the do_notify_parent time
      computation.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Reviewed-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      32bd671d
    • Ingo Molnar's avatar
      Merge branch 'sched/urgent' into timers/urgent · 83895147
      Ingo Molnar authored
      Merging it here because an upcoming timers/urgent fix relies on
      a change already in sched/urgent and not yet upstream.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      83895147
    • Pavel Emelyanov's avatar
      x86: fix hpet timer reinit for x86_64 · a6a95406
      Pavel Emelyanov authored
      There's a small problem with hpet_rtc_reinit function - it checks
      for the:
      
      	hpet_readl(HPET_COUNTER) - hpet_t1_cmp > 0
      
      to continue increasing both the HPET_T1_CMP (register) and the
      hpet_t1_cmp (variable).
      
      But since the HPET_COUNTER is always 32-bit, if the hpet_t1_cmp
      is 64-bit this condition will always be FALSE once the latter hits
      the 32-bit boundary, and we can have a situation, when we don't
      increase the HPET_T1_CMP register high enough.
      
      The result - timer stops ticking, since HPET_T1_CMP becomes less,
      than the COUNTER and never increased again.
      
      The solution is (based on Linus's suggestion) to not compare 64-bits
      (on 64-bit x86), but to do the comparison on 32-bit signed
      integers.
      Reported-by: default avatarKirill Korotaev <dev@openvz.org>
      Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      a6a95406
  4. 04 Feb, 2009 1 commit
    • Suresh Siddha's avatar
      sched: fix nohz load balancer on cpu offline · 483b4ee6
      Suresh Siddha authored
      Christian Borntraeger reports:
      
      > After a logical cpu offline, even on a complete idle system, there
      > is one cpu with full ticks. It turns out that nohz.cpu_mask has the
      > the offlined cpu still set.
      >
      > In select_nohz_load_balancer() we check if the system is completely
      > idle to turn of load balancing. We compare cpu_online_map with
      > nohz.cpu_mask.  Since cpu_online_map is updated on cpu unplug,
      > but nohz.cpu_mask is not, the check fails and the scheduler believes
      > that we need an "idle load balancer" even on a fully idle system.
      > Since the ilb cpu does not deactivate the timer tick this breaks NOHZ.
      
      Fix the select_nohz_load_balancer() to not set the nohz.cpu_mask
      while a cpu is going offline.
      Reported-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
      Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
      Tested-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      483b4ee6
  5. 03 Feb, 2009 12 commits
  6. 02 Feb, 2009 19 commits