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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
	"David S. Ahern" <daahern@cisco.com>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 1/2] perf tools: Add reference timestamp to perf header
Date: Mon, 13 Dec 2010 19:10:24 +0100	[thread overview]
Message-ID: <1292263824.6803.391.camel@twins> (raw)
In-Reply-To: <20101213180548.GF1691@nowhere>

On Mon, 2010-12-13 at 19:05 +0100, Frederic Weisbecker wrote:
> 
> There is one writer per cpu and a (stupid) multiplexing at report time.
> It was working. Just the sorting on report time was (stupidly) slow.
> 
> I should perhaps rebase that branch and try to make something with it. 

Right, so we need to have a small ~16 events sort window per file [*],
and then a merge-sort over all files, simply consumer the most recent
event across all files.

We can have out-of-order events on a single cpu due to nesting and
taking the time-stamp _before_ we reserve the buffer. We could cure some
of this by moving the perf_clock() call from
__perf_event_header__init_id()/perf_prepare_sample() to
__perf_event_output_id_sample()/perf_output_sample().

  reply	other threads:[~2010-12-13 18:10 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-08  1:54 [PATCH 0/2] perf tools: add reference timestamp and use it in time history dump David Ahern
2010-12-08  1:54 ` [PATCH 1/2] perf tools: Add reference timestamp to perf header David Ahern
2010-12-12 20:16   ` Frederic Weisbecker
2010-12-13 13:15     ` Arnaldo Carvalho de Melo
2010-12-13 16:58       ` Arnaldo Carvalho de Melo
2010-12-13 14:39     ` David S. Ahern
2010-12-13 15:54       ` Frederic Weisbecker
2010-12-13 16:48         ` Arnaldo Carvalho de Melo
2010-12-13 17:09           ` Frederic Weisbecker
2010-12-13 17:11             ` Peter Zijlstra
2010-12-13 17:13               ` Peter Zijlstra
2010-12-13 17:23                 ` Frederic Weisbecker
2010-12-13 17:37                   ` Peter Zijlstra
2010-12-13 17:50                     ` Frederic Weisbecker
2010-12-13 17:15               ` Frederic Weisbecker
2010-12-13 17:18                 ` Peter Zijlstra
2010-12-13 17:22                   ` Arnaldo Carvalho de Melo
2010-12-13 17:35                     ` Peter Zijlstra
2010-12-13 17:43                       ` Arnaldo Carvalho de Melo
2010-12-13 17:51                         ` Peter Zijlstra
2010-12-13 18:05                           ` Frederic Weisbecker
2010-12-13 18:10                             ` Peter Zijlstra [this message]
2010-12-13 17:47                       ` Peter Zijlstra
2010-12-13 17:49                         ` David S. Ahern
2010-12-13 17:57                           ` Peter Zijlstra
2010-12-13 18:01                             ` David S. Ahern
2010-12-13 18:06                               ` Peter Zijlstra
2010-12-13 18:20                                 ` David S. Ahern
2010-12-13 19:08                               ` Arnaldo Carvalho de Melo
2010-12-13 19:15                                 ` David S. Ahern
2010-12-13 19:22                                   ` Peter Zijlstra
2010-12-13 19:17                                 ` Peter Zijlstra
2010-12-13 17:48                       ` Peter Zijlstra
2010-12-13 17:14             ` Arnaldo Carvalho de Melo
2010-12-13 17:36           ` David S. Ahern
2010-12-13 17:51             ` Arnaldo Carvalho de Melo
2010-12-08  1:54 ` [PATCH 2/2] perf tools: Add option to show time history of event samples David Ahern
2010-12-08 21:06   ` Arnaldo Carvalho de Melo
2010-12-12 21:32   ` Frederic Weisbecker
2010-12-09 17:18 ` [PATCH 0/2] perf tools: add reference timestamp and use it in time history dump Arnaldo Carvalho de Melo
2010-12-12 21:39   ` Frederic Weisbecker
  -- strict thread matches above, loose matches on Subject: below --
2010-11-29 23:07 [PATCH 0/2] perf tools: reference timestamp and " David Ahern
2010-11-29 23:07 ` [PATCH 1/2] perf tools: add reference timestamp to perf header David Ahern

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