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* perf_event wakeup_events = 0
@ 2019-09-06 23:28 Theodore Dubois
  2019-09-07 13:40 ` Valdis Klētnieks
  0 siblings, 1 reply; 6+ messages in thread
From: Theodore Dubois @ 2019-09-06 23:28 UTC (permalink / raw)
  To: a.p.zijlstra; +Cc: linux-kernel, kernelnewbies

The man page for perf_event_open(2) says that recent kernels treat a 0
value for wakeup_events the same as 1, which I believe means it will
notify after a single sample. However, strace on perf(1) shows that it
uses wakeup_events=0, and it's definitely not waking up on every
sample (it seems to be waking up every few seconds.)
tools/perf/design.txt says "Normally a notification is generated for
every page filled". Is the documentation wrong, or am I
misunderstanding something?

~Theodore

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2019-09-06 23:28 perf_event wakeup_events = 0 Theodore Dubois
2019-09-07 13:40 ` Valdis Klētnieks
2019-09-07 16:14   ` Theodore Dubois
2019-09-07 22:00     ` Valdis Klētnieks
2019-09-07 22:45     ` Valdis Klētnieks
2019-09-07 23:27       ` Theodore Dubois

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