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  1. 05 2月, 2009 5 次提交
    • P
      timers: split process wide cpu clocks/timers · 4cd4c1b4
      由 Peter Zijlstra 提交于 
      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: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      4cd4c1b4
    • P
      signal: re-add dead task accumulation stats. · 32bd671d
      由 Peter Zijlstra 提交于 
      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: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      32bd671d
    • I
      Merge branch 'sched/urgent' into timers/urgent · 83895147
      由 Ingo Molnar 提交于 
      Merging it here because an upcoming timers/urgent fix relies on
a change already in sched/urgent and not yet upstream.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      83895147
    • P
      x86: fix hpet timer reinit for x86_64 · a6a95406
      由 Pavel Emelyanov 提交于 
      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: NKirill Korotaev <dev@openvz.org>
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      a6a95406
    • S
      sched: fix nohz load balancer on cpu offline · 483b4ee6
      由 Suresh Siddha 提交于 
      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: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Tested-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      483b4ee6
  3. 03 2月, 2009 26 次提交
  5. 02 2月, 2009 9 次提交