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  1. 18 May, 2009 1 commit
  3. 17 May, 2009 4 commits
    • Ingo Molnar's avatar
      perf_counter, x86: fix zero irq_period counters · d2517a49
      Ingo Molnar authored 
      The quirk to irq_period unearthed an unrobustness we had in the
hw_counter initialization sequence: we left irq_period at 0, which
was then quirked up to 2 ... which then generated a _lot_ of
interrupts during 'perf stat' runs, slowed them down and skewed
the counter results in general.

Initialize irq_period to the maximum instead.

[ Impact: fix perf stat results ]

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      d2517a49
    • Ingo Molnar's avatar
      perf_counter: fix threaded task exit · 0203026b
      Ingo Molnar authored 
      Flushing counters in __exit_signal() with irqs disabled is not
a good idea as perf_counter_exit_task() acquires mutexes. So
flush it before acquiring the tasklist lock.

(Note, we still need a fix for when the PID has been unhashed.)

[ Impact: fix crash with inherited counters ]

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0203026b
    • Peter Zijlstra's avatar
      perf_counter: Fix counter inheritance · 856d56b9
      Peter Zijlstra authored 
      Srivatsa Vaddagiri reported that a Java workload triggers this
warning in kernel/exit.c:

   WARN_ON_ONCE(!list_empty(&tsk->perf_counter_ctx.counter_list));

Add the inherited counter propagation on self-detach, this could
cause counter leaks and incomplete stats in threaded code like
the below:

  #include <pthread.h>
  #include <unistd.h>

  void *thread(void *arg)
  {
          sleep(5);
          return NULL;
  }

  void main(void)
  {
          pthread_t thr;
          pthread_create(&thr, NULL, thread, NULL);
  }
Reported-by: default avatarSrivatsa Vaddagiri <vatsa@in.ibm.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      856d56b9
    • Peter Zijlstra's avatar
      perf_counter: Fix inheritance cleanup code · 8bc20959
      Peter Zijlstra authored 
      Clean up code that open-coded the list_{add,del}_counter() code in
__perf_counter_exit_task() which consequently diverged. This could
lead to software counter crashes.

Also, fold the ctx->nr_counter inc/dec into those functions and clean
up some of the related code.

[ Impact: fix potential sw counter crash, cleanup ]
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      8bc20959
  5. 16 May, 2009 1 commit
  7. 15 May, 2009 34 commits