From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vweaver1@eecs.utk.edu>,
linux-kernel@vger.kernel.org, mingo@elte.hu, paulus@samba.org,
acme@redhat.com
Subject: Re: perf: [patch] regression with PERF_EVENT_IOC_REFRESH
Date: Tue, 31 May 2011 09:23:13 +0200 [thread overview]
Message-ID: <1306826593.2530.7.camel@twins> (raw)
In-Reply-To: <Pine.LNX.4.64.1105302129210.7601@pianoman.cluster.toy>
On Mon, 2011-05-30 at 21:33 -0400, Vince Weaver wrote:
> the problem was the mentioned commit tried to optimize the use of
> watermark and wakeup_watermark without taking into account that
> wakeup_watermark is a union with wakeup_events.
Note that wake_events isn't related to IOC_REFRESH, wake_events is how
much events to buffer in the mmap-buffer before issuing a wakeup.
IOC_REFRESH increments event_limit, which is how many events to run
before disabling yourself.
What I gather is that due to that SIGIO bug (fixed by f506b3dc0e), you
had to have both an mmap and a wakeup in order for that signal to
arrive.
next prev parent reply other threads:[~2011-05-31 7:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-23 20:04 perf: regression with PERF_EVENT_IOC_REFRESH Vince Weaver
2011-05-23 20:22 ` Peter Zijlstra
2011-05-24 6:20 ` Vince Weaver
2011-05-24 10:30 ` Peter Zijlstra
2011-05-24 15:04 ` Vince Weaver
2011-05-24 15:10 ` Peter Zijlstra
2011-05-24 15:40 ` Ingo Molnar
2011-05-24 20:31 ` Vince Weaver
2011-05-25 10:39 ` Ingo Molnar
2011-05-25 21:24 ` Vince Weaver
2011-05-24 17:53 ` Vince Weaver
2011-05-24 15:11 ` Peter Zijlstra
2011-05-24 15:18 ` Peter Zijlstra
2011-05-24 21:48 ` Vince Weaver
2011-05-28 3:38 ` Vince Weaver
2011-05-28 10:22 ` Peter Zijlstra
2011-05-28 13:26 ` perf: definition of a "regression" Vince Weaver
2011-06-02 7:45 ` Ingo Molnar
2011-05-29 16:54 ` perf: regression with PERF_EVENT_IOC_REFRESH Vince Weaver
2011-05-31 1:33 ` perf: [patch] " Vince Weaver
2011-05-31 7:17 ` Peter Zijlstra
2011-05-31 7:23 ` Peter Zijlstra [this message]
2011-05-31 13:49 ` Vince Weaver
2011-05-31 15:52 ` Peter Zijlstra
2011-05-31 16:39 ` Vince Weaver
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