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  1. 09 May, 2010 7 commits
    • Frederic Weisbecker's avatar
      perf lock: Always check min AND max wait time · 90c0e5fc
      Frederic Weisbecker authored 
      When a lock is acquired after beeing contended, we update the
wait time statistics for the given lock.
But if the min wait time is updated, we don't check the max wait
time. This is wrong because the first time we update the wait time,
we want to update both min and max wait time.

Before:
	Name   acquired  contended total wait (ns)   max wait (ns)   min wait (ns)
	key          8          1           21656           0           21656

After:
	Name   acquired  contended total wait (ns)   max wait (ns)   min wait (ns)
	key          8          1           21656           21656           21656
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
      90c0e5fc
    • Frederic Weisbecker's avatar
      perf: Fix perf lock bad rate · 5efe08cf
      Frederic Weisbecker authored 
      Fix the cast made to get the bad rate. It is made in the result
instead of the operands. We need the operands to be cast in double,
otherwise the result will always be zero.
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
      5efe08cf
    • Frederic Weisbecker's avatar
      perf: Humanize lock flags in perf lock · 84c7a217
      Frederic Weisbecker authored 
      Use an enum instead of plain constants for lock flags.
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
      84c7a217
    • Frederic Weisbecker's avatar
      perf: Cleanup perf lock broken states · 10350ec3
      Frederic Weisbecker authored 
      Use enum to get a human view of bad_hist indexes and
put bad histogram output in its own function.
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
      10350ec3
    • Hitoshi Mitake's avatar
      perf lock: Add "info" subcommand for dumping misc information · 26242d85
      Hitoshi Mitake authored 
      This adds the "info" subcommand to perf lock which can be used
to dump metadata like threads or addresses of lock instances.
"map" was removed because info should do the work for it.

This will be useful not only for debugging but also for ordinary
analyzing.

v2: adding example of usage
% sudo ./perf lock info -t
 | Thread ID: comm
 | 	 0: swapper
 |         1: init
 |        18: migration/5
 |        29: events/2
 |        32: events/5
 |        33: events/6
...

% sudo ./perf lock info -m
| Address of instance: name of class
|  0xffff8800b95adae0: &(&sighand->siglock)->rlock
|  0xffff8800bbb41ae0: &(&sighand->siglock)->rlock
|  0xffff8800bf165ae0: &(&sighand->siglock)->rlock
|  0xffff8800b9576a98: &p->cred_guard_mutex
|  0xffff8800bb890a08: &(&p->alloc_lock)->rlock
|  0xffff8800b9522a08: &(&p->alloc_lock)->rlock
|  0xffff8800bb8aaa08: &(&p->alloc_lock)->rlock
|  0xffff8800bba72a08: &(&p->alloc_lock)->rlock
|  0xffff8800bf18ea08: &(&p->alloc_lock)->rlock
|  0xffff8800b8a0d8a0: &(&ip->i_lock)->mr_lock
|  0xffff88009bf818a0: &(&ip->i_lock)->mr_lock
|  0xffff88004c66b8a0: &(&ip->i_lock)->mr_lock
|  0xffff8800bb6478a0: &(shost->host_lock)->rlock

v3: fixed some problems Frederic pointed out
 * better rbtree tracking in dump_threads()
 * removed printf() and used pr_info() and pr_debug()
Signed-off-by: default avatarHitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
LKML-Reference: <1272863520-16179-1-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      26242d85
    • Frederic Weisbecker's avatar
      perf: Provide a new deterministic events reordering algorithm · d6b17beb
      Frederic Weisbecker authored 
      The current events reordering algorithm is based on a heuristic that
gets broken once we deal with a very fast flow of events.

Indeed the time period based flushing is not suitable anymore
in the following case, assuming we have a flush period of two
seconds.

    CPU 0           |        CPU 1
                    |
  cnt1 timestamps   |      cnt1 timestamps
                    |
    0               |         0
    1               |         1
    2               |         2
    3               |         3
    [...]           |        [...]
    4 seconds later

If we spend too much time to read the buffers (case of a lot of
events to record in each buffers or when we have a lot of CPU buffers
to read), in the next pass the CPU 0 buffer could contain a slice
of several seconds of events. We'll read them all and notice we've
reached the period to flush. In the above example we flush the first
half of the CPU 0 buffer, then we read the CPU 1 buffer where we
have events that were on the flush slice and then the reordering
fails.

It's simple to reproduce with:

	perf lock record perf bench sched messaging

To solve this, we use a new solution that doesn't rely on an
heuristical time slice period anymore but on a deterministic basis
based on how perf record does its job.

perf record saves the buffers through passes. A pass is a tour
on every buffers from every CPUs. This is made in order: for
each CPU we read the buffers of every counters. So the more
buffers we visit, the later will be the timstamps of their events.

When perf record finishes a pass it records a
PERF_RECORD_FINISHED_ROUND pseudo event.
We record the max timestamp t found in the pass n. Assuming these
timestamps are monotonic across cpus, we know that if a buffer
still has events with timestamps below t, they will be all available
and then read in the pass n + 1.
Hence when we start to read the pass n + 2, we can safely flush every
events with timestamps below t.

      ============ PASS n =================
         CPU 0         |   CPU 1
                       |
      cnt1 timestamps  |   cnt2 timestamps
            1          |         2
            2          |         3
            -          |         4  <--- max recorded

      ============ PASS n + 1 ==============
         CPU 0         |   CPU 1
                       |
      cnt1 timestamps  |   cnt2 timestamps
            3          |         5
            4          |         6
            5          |         7 <---- max recorded

        Flush every events below timestamp 4

      ============ PASS n + 2 ==============
         CPU 0         |   CPU 1
                       |
      cnt1 timestamps  |   cnt2 timestamps
            6          |         8
            7          |         9
            -          |         10

        Flush every events below timestamp 7
        etc...

It also works on perf.data versions that don't have
PERF_RECORD_FINISHED_ROUND pseudo events. The difference is that
the events will be only flushed in the end of the perf.data
processing. It will then consume more memory and scale less with
large perf.data files.
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
      d6b17beb
    • Frederic Weisbecker's avatar
      perf: Introduce a new "round of buffers read" pseudo event · 98402807
      Frederic Weisbecker authored 
      In order to provide a more rubust and deterministic reordering
algorithm, we need to know when we reach a point where we just
did a pass through over every counter buffers to read every thing
they had.

This patch introduces a new PERF_RECORD_FINISHED_ROUND pseudo event
that only consist in an event header and doesn't need to contain
anything.
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
      98402807
  3. 08 May, 2010 8 commits
  5. 07 May, 2010 14 commits
  7. 06 May, 2010 1 commit
  9. 05 May, 2010 10 commits
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