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From: David Ahern <dsahern@gmail.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org,
	Corey Ashford <cjashfor@linux.vnet.ibm.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Ingo Molnar <mingo@elte.hu>, Namhyung Kim <namhyung@kernel.org>,
	Paul Mackerras <paulus@samba.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCHv2 00/25] perf tool: Add support for multiple data file storage
Date: Mon, 09 Sep 2013 08:03:21 -0700	[thread overview]
Message-ID: <522DE339.4030004@gmail.com> (raw)
In-Reply-To: <20130909143134.GA27974@krava.redhat.com>

On 9/9/13 7:31 AM, Jiri Olsa wrote:
> On Mon, Sep 09, 2013 at 07:11:11AM -0700, David Ahern wrote:
>> On 9/9/13 7:03 AM, Jiri Olsa wrote:
>>> my usage currently is to having this running during the day:
>>> (well whenever I remember to run it.. ;-) )
>>>
>>>    [jolsa@krava perf]$ sudo ./perf record -g -M 1m -a
>>>
>>> and checking report when the system or app get stuck
>>>
>>> with multiple files I can just easily (or automaticaly)
>>> remove old ones without restarting session
>>
>> Aren't you losing potentially important events by doing that --
>> FORK, COMM, MMAP?
>
> those are synthesized for each file via synthesize_record
> function, see:
>
> [PATCH 19/25] perf tools: Move synthesizing into single function

Ok. haven't had time to look through your 2 large patch sets.

Seems like a lot of repetitive work on a loaded system. The overhead of 
the task events will dominate compared to the samples.

>
>>
>> I have a flight recorder style command that address this problem
>> (long-running/daemons) by processing task events and then stashing
>> the sample events on a time-ordered list with chopping to maintain
>> the time window.
>
> so far I noticed there could be race among EXIT and remaining
> SAMPLE events on another CPU mmap than EXIT event.. ending up
> with EXIT being stored in the old file, while SAMPLEs will get
> to the new one
>
> I was thinking about some 'perf daemon' so I dont need to run that
> manually.. seems similar to what you did

Right now I focus on scheduling events. This latest version of it can be 
easily recycled for other use cases. Some work would be needed to dump 
events to a file versus dumping processed information.

I am in San Jose this week. Not sure if I will have time to finish it to 
a point of pushing out patches, but maybe I can push to github in the 
next couple of days.

David

  reply	other threads:[~2013-09-09 15:03 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-01 10:36 [PATCHv2 00/25] perf tool: Add support for multiple data file storage Jiri Olsa
2013-09-01 10:36 ` [PATCH 01/25] perf tools: Check mmap pages value early Jiri Olsa
2013-10-15  5:24   ` [tip:perf/core] " tip-bot for Jiri Olsa
2013-09-01 10:36 ` [PATCH 02/25] perf tools: Add possibility to specify mmap size Jiri Olsa
2013-10-15  5:25   ` [tip:perf/core] " tip-bot for Jiri Olsa
2013-09-01 10:36 ` [PATCH 03/25] perf tools: Introduce perf_evlist__new_default function Jiri Olsa
2013-10-15  5:25   ` [tip:perf/core] perf evlist: " tip-bot for Jiri Olsa
2013-09-01 10:36 ` [PATCH 04/25] perf tools: Adding throttle event data struct support Jiri Olsa
2013-10-15  5:25   ` [tip:perf/core] " tip-bot for Jiri Olsa
2013-09-01 10:36 ` [PATCH 05/25] perf tests: Add simple session read/write test Jiri Olsa
2013-09-01 10:36 ` [PATCH 06/25] perf tests: Add session reading test for little endian perf data Jiri Olsa
2013-09-01 10:36 ` [PATCH 07/25] perf tests: Add session reading test for big " Jiri Olsa
2013-09-01 10:36 ` [PATCH 08/25] perf doc: Add perf data file documentation Jiri Olsa
2013-09-01 10:36 ` [PATCH 09/25] perf tools: Introduce perf data file version CHECK macro Jiri Olsa
2013-09-01 10:36 ` [PATCH 10/25] perf tools: Introduce swap_features function Jiri Olsa
2013-09-01 10:36 ` [PATCH 11/25] perf tools: Introduce swap_header function Jiri Olsa
2013-09-01 10:36 ` [PATCH 12/25] perf tools: Separate version 2 specific perf data header bits Jiri Olsa
2013-09-01 10:36 ` [PATCH 13/25] perf tools: Using evlist as a holder for event_desc feature Jiri Olsa
2013-09-01 10:36 ` [PATCH 14/25] perf tools: Introduce perf.data version 3 format Jiri Olsa
2013-09-01 10:36 ` [PATCH 15/25] perf tools: Add perf data version 3 header swap Jiri Olsa
2013-09-01 10:36 ` [PATCH 16/25] perf tools: Add perf data version 3 header read Jiri Olsa
2013-09-01 10:36 ` [PATCH 17/25] perf tools: Add perf.data version 3 header write Jiri Olsa
2013-09-01 10:36 ` [PATCH 18/25] perf tools: Get rid of post_processing_offset in record command Jiri Olsa
2013-09-01 10:36 ` [PATCH 19/25] perf tools: Move synthesizing into single function Jiri Olsa
2013-09-01 10:36 ` [PATCH 20/25] perf tools: Add perf_data_file__open interface to data object Jiri Olsa
2013-09-01 10:36 ` [PATCH 21/25] perf tools: Separating data file properties from session Jiri Olsa
2013-09-01 10:36 ` [PATCH 22/25] perf tests: Add session reading test for little endian perf data v3 Jiri Olsa
2013-09-01 10:36 ` [PATCH 23/25] perf tests: Add session reading test for big " Jiri Olsa
2013-09-01 10:36 ` [PATCH 24/25] perf tools: Add multi file '-M' option for record command Jiri Olsa
2013-09-02  7:52   ` Adrian Hunter
2013-09-02  8:37     ` Jiri Olsa
2013-09-02  9:11       ` Adrian Hunter
2013-09-02  9:40         ` Jiri Olsa
2013-09-01 10:36 ` [PATCH 25/25] perf tools: Have the process properly sythesized in subsequent data files Jiri Olsa
2013-09-02  2:42 ` [PATCHv2 00/25] perf tool: Add support for multiple data file storage Andi Kleen
2013-09-09 11:17 ` Peter Zijlstra
2013-09-09 11:36   ` Jiri Olsa
2013-09-09 11:55     ` Peter Zijlstra
2013-09-09 14:03       ` Jiri Olsa
2013-09-09 14:11         ` David Ahern
2013-09-09 14:31           ` Jiri Olsa
2013-09-09 15:03             ` David Ahern [this message]
2013-09-14 18:32               ` David Ahern
2013-09-09 16:06           ` Ingo Molnar
2013-09-10 17:29             ` David Ahern
2013-09-10  6:54   ` Adrian Hunter
2013-09-10  9:15     ` Peter Zijlstra
2013-09-10  8:57   ` Namhyung Kim

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