Skip to content
GitLab
  1. May 11, 2009
    • Paul Mackerras's avatar
      perf_counter: don't count scheduler ticks as context switches · a08b159f
      Paul Mackerras authored 
      

The context-switch software counter gives inflated values at present
because each scheduler tick and each process-wide counter
enable/disable prctl gets counted as a context switch.

This happens because perf_counter_task_tick, perf_counter_task_disable
and perf_counter_task_enable all call perf_counter_task_sched_out,
which calls perf_swcounter_event to record a context switch event.

This fixes it by introducing a variant of perf_counter_task_sched_out
with two underscores in front for internal use within the perf_counter
code, and makes perf_counter_task_{tick,disable,enable} call it.  This
variant doesn't record a context switch event, and takes a struct
perf_counter_context *.  This adds the new variant rather than
changing the behaviour or interface of perf_counter_task_sched_out
because that is called from other code.

[ Impact: fix inflated context-switch event counts ]

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <18951.48034.485580.498953@drongo.ozlabs.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      a08b159f
    • Paul Mackerras's avatar
      perf_counter: Put whole group on when enabling group leader · 6751b71e
      Paul Mackerras authored 
      

Currently, if you have a group where the leader is disabled and there
are siblings that are enabled, and then you enable the leader, we only
put the leader on the PMU, and not its enabled siblings.  This is
incorrect, since the enabled group members should be all on or all off
at any given point.

This fixes it by adding a call to group_sched_in in
__perf_counter_enable in the case where we're enabling a group leader.

To avoid the need for a forward declaration this also moves
group_sched_in up before __perf_counter_enable.  The actual content of
group_sched_in is unchanged by this patch.

[ Impact: fix bug in counter enable code ]

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <18951.34946.451546.691693@drongo.ozlabs.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      6751b71e
    • Mike Galbraith's avatar
      perf_counter, x86: clean up throttling printk · 88233923
      Mike Galbraith authored 
      

s/PERFMON/perfcounters for perfcounter interrupt throttling warning.

'perfmon' is the CPU feature name that is Intel-only, while we do
throttling in a generic way.

[ Impact: cleanup ]

Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      88233923
  3. May 10, 2009
  5. May 09, 2009
  7. May 06, 2009
  9. May 05, 2009
    • Ingo Molnar's avatar
      perf_counter: fix fixed-purpose counter support on v2 Intel-PERFMON · 066d7dea
      Ingo Molnar authored 
      Fixed-purpose counters stopped working in a simple 'perf stat ls' run:

   <not counted>  cache references
   <not counted>  cache misses

Due to:

  ef7b3e09

: perf_counter, x86: remove vendor check in fixed_mode_idx()

Which made x86_pmu.num_counters_fixed matter: if it's nonzero, the
fixed-purpose counters are utilized.

But on v2 perfmon this field is not set (despite there being
fixed-purpose PMCs). So add a quirk to set the number of fixed-purpose
counters to at least three.

[ Impact: add quirk for three fixed-purpose counters on certain Intel CPUs ]

Cc: Robert Richter <robert.richter@amd.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1241002046-8832-28-git-send-email-robert.richter@amd.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      066d7dea
    • Ingo Molnar's avatar
      perf_counter: convert perf_resource_mutex to a spinlock · 1dce8d99
      Ingo Molnar authored 
      

Now percpu counters can be initialized very early. But the init
sequence uses mutex_lock(). Fortunately, perf_resource_mutex should
be a spinlock anyway, so convert it.

[ Impact: fix crash due to early init mutex use ]

LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      1dce8d99
    • Ingo Molnar's avatar
      perf_counter: initialize the per-cpu context earlier · 0d905bca
      Ingo Molnar authored 
      

percpu scheduling for perfcounters wants to take the context lock,
but that lock first needs to be initialized. Currently it is an
early_initcall() - but that is too late, the task tick runs much
sooner than that.

Call it explicitly from the scheduler init sequence instead.

[ Impact: fix access-before-init crash ]

LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0d905bca
    • Peter Zijlstra's avatar
      perf_counter: x86: fixup nmi_watchdog vs perf_counter boo-boo · ba77813a
      Peter Zijlstra authored 
      

Invert the atomic_inc_not_zero() test so that we will indeed detect the
first activation.

Also rename the global num_counters, since its easy to confuse with
x86_pmu.num_counters.

[ Impact: fix non-working perfcounters on AMD CPUs, cleanup ]

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1241455664.7620.4938.camel@twins>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      ba77813a
    • Ingo Molnar's avatar
      perf_counter: round-robin per-CPU counters too · b82914ce
      Ingo Molnar authored 
      

This used to be unstable when we had the rq->lock dependencies,
but now that they are that of the past we can turn on percpu
counter RR too.

[ Impact: handle counter over-commit for per-CPU counters too ]

LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b82914ce
  11. May 03, 2009
  13. May 02, 2009
  15. May 01, 2009
  17. Apr 30, 2009