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From: Andrew Wagin <avagin@gmail.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Vagin <avagin@openvz.org>,
	linux-kernel@vger.kernel.org, Arun Sharma <asharma@fb.com>,
	Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@elte.hu>,
	Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
	devel@openvz.org
Subject: Re: [PATCH 2/7] event: don't divide events if it has field period
Date: Thu, 17 Nov 2011 11:22:20 +0300	[thread overview]
Message-ID: <CANaxB-xOQr=gHGRwPUoZN7cMdss48Q5A2XJvU7Kg+MaCZeqX9w@mail.gmail.com> (raw)
In-Reply-To: <4EBCF0EB.8080304@gmail.com>

Hello Peter,

11 ноября 2011 г. 13:54 пользователь Andrew Vagin <avagin@gmail.com> написал:
> On 11/09/2011 03:55 PM, Peter Zijlstra wrote:
>>
>> On Mon, 2011-11-07 at 15:54 +0300, Andrew Vagin wrote:
>>>
>>> This patch solves the following problem:
>>>
>>> Now some samples may be lost due to throttling. The number of samples is
>>> restricted by sysctl_perf_event_sample_rate/HZ.  A trace event is
>>> divided on some samples according to event's period.  I don't sure, that
>>> we should generate more than one sample on each trace event. I think the
>>> better way to use SAMPLE_PERIOD.
>>
>> It would be yes, but this code predates that, also it needs to work even
>> if the user doesn't provide SAMPLE_PERIOD.

I have not understood exactly what I should do now.
I'm going to send the third version of this patches. New version
contains only a small fix according with the comment for path 4/7.
In new version I am not going to fix the problem about which we
discussed early. I have some reasons for it:

*  It's another task. My decision is more effective for my task and  I
believe that exists many cases where my decision may be suitable. I
want to say, that it may be in kernel, event if the problem would not
exist at all.
* __perf_count() has been broken for a long time and nobody reports
this problem, so we can say, that the problem isn't urgent.
* Only few events sched:sched_stat_* are affected by this problem.
* I am not sure, that we should to solve this problem. The "problem"
may be not a problem at all. We have ability to customize
sample_period and we have events about that some events were
throttled.

If you have any objection, send them to me.

  reply	other threads:[~2011-11-17  8:22 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-07 12:54 [PATCH 0/7] Profiling sleep times (v2) Andrew Vagin
2011-11-07 12:54 ` [PATCH 1/7] perf: use event_name() to get an event name Andrew Vagin
2011-11-07 12:54 ` [PATCH 2/7] event: don't divide events if it has field period Andrew Vagin
2011-11-09 11:55   ` Peter Zijlstra
2011-11-11  9:54     ` Andrew Vagin
2011-11-17  8:22       ` Andrew Wagin [this message]
2011-11-17  8:45         ` Peter Zijlstra
2011-11-18 23:36   ` [tip:perf/core] events: Don't " tip-bot for Andrew Vagin
2011-11-07 12:54 ` [PATCH 3/7] perf: add ability to record event period Andrew Vagin
2011-11-07 12:54 ` [PATCH 4/7] perf: add ability to change event according to sample Andrew Vagin
2011-11-07 21:14   ` David Ahern
2011-11-07 12:54 ` [PATCH 5/7] perf: teach "perf inject" to work with files Andrew Vagin
2011-11-07 12:54 ` [PATCH 6/7] perf: teach perf inject to merge sched_stat_* and sched_switch events Andrew Vagin
2011-11-07 12:54 ` [PATCH 7/7] perf: add scripts for profiling sleep times Andrew Vagin

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