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 [thread overview]
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
_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
next reply other threads:[~2019-09-16 15:51 UTC|newest]
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 ` perf_event wakeup_events = 0 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAN3rvwA+Dnqj4O79f6rNfO50VjbAC3YwJ7CW2ze2aBLzkSJRgQ@mail.gmail.com \
--to=tbodt@google.com \
--cc=a.p.zijlstra@chello.nl \
--cc=kernelnewbies@kernelnewbies.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).