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From: Theodore Dubois <tbodt@google.com>
To: a.p.zijlstra@chello.nl
Cc: linux-kernel@vger.kernel.org, kernelnewbies@kernelnewbies.org
Subject: perf_event wakeup_events = 0
Date: Fri, 6 Sep 2019 16:28:24 -0700
Message-ID: <CAN3rvwA+Dnqj4O79f6rNfO50VjbAC3YwJ7CW2ze2aBLzkSJRgQ@mail.gmail.com> (raw)

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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Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-06 23:28 Theodore Dubois [this message]
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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