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linux/kernel
Peter Zijlstra bce379bf35 perf_counter: minimize context time updates
Push the update_context_time() calls up the stack so that we get less
invokations and thereby a less noisy output:

before:

 # ./perfstat -e 1:0 -e 1:1 -e 1:1 -e 1:1 -l ls > /dev/null

 Performance counter stats for 'ls':

      10.163691  cpu clock ticks      (msecs)  (scaled from 98.94%)
      10.215360  task clock ticks     (msecs)  (scaled from 98.18%)
      10.185549  task clock ticks     (msecs)  (scaled from 98.53%)
      10.183581  task clock ticks     (msecs)  (scaled from 98.71%)

 Wall-clock time elapsed:    11.912858 msecs

after:

 # ./perfstat -e 1:0 -e 1:1 -e 1:1 -e 1:1 -l ls > /dev/null

 Performance counter stats for 'ls':

       9.316630  cpu clock ticks      (msecs)
       9.280789  task clock ticks     (msecs)
       9.280789  task clock ticks     (msecs)
       9.280789  task clock ticks     (msecs)

 Wall-clock time elapsed:     9.574872 msecs

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090406094518.618876874@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-07 10:49:01 +02:00
..
2009-04-02 19:04:55 -07:00
2009-01-14 18:09:02 +01:00
2009-03-13 11:25:53 +01:00
2009-03-30 22:05:16 +10:30
2009-01-06 11:07:15 +01:00
2009-04-07 10:49:01 +02:00
2009-04-03 16:42:35 +01:00
2009-04-03 16:42:35 +01:00
2009-03-24 10:52:46 +11:00