From: David Ahern <david.ahern@oracle.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Frederic Weisbecker <fweisbec@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
Stephane Eranian <eranian@google.com>,
Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [PATCH] perf record: Allow poll timeout to be specified
Date: Wed, 25 Mar 2015 08:41:07 -0600 [thread overview]
Message-ID: <5512C903.6070905@oracle.com> (raw)
In-Reply-To: <20150325121425.GA13759@kernel.org>
On 3/25/15 6:14 AM, Arnaldo Carvalho de Melo wrote:
> If David doesn't come up with something I'll probably will, as making
> 'trace' use the ordered_samples, like 'perf top' does (initially with
> some arbitrary reasonable poll timeout value), is a low hanging fruit to
> get those multi-CPU tracepoints sorted until I get something better in
> place...
I have thought about it. It needs to be an adaptive algorithm:
1. start at 100 msec.
2. Read the maps. How much data are there (not events, but data size)?
3. Adjust poll timeout up or down with some heuristic -- maybe something
similar to the algorithm perf-top uses for removing entries from the
histograms.
That said, I still thinking giving the user control is not a crazy idea.
David
next prev parent reply other threads:[~2015-03-25 14:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-24 16:09 [PATCH] perf record: Allow poll timeout to be specified David Ahern
2015-03-24 16:12 ` Ingo Molnar
2015-03-24 16:18 ` David Ahern
2015-03-24 21:21 ` Arnaldo Carvalho de Melo
2015-03-25 9:11 ` Ingo Molnar
2015-03-25 12:14 ` Arnaldo Carvalho de Melo
2015-03-25 14:41 ` David Ahern [this message]
2015-03-25 18:20 ` Ingo Molnar
2015-03-25 12:38 ` Jiri Olsa
2015-03-25 14:37 ` David Ahern
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