From: David Ahern <dsahern@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>,
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: Tue, 10 Sep 2013 10:29:20 -0700 [thread overview]
Message-ID: <522F56F0.4040206@gmail.com> (raw)
In-Reply-To: <20130909160608.GB25555@gmail.com>
On 9/9/13 9:06 AM, Ingo Molnar wrote:
>> Aren't you losing potentially important events by doing that -- FORK,
>> COMM, MMAP?
>
> I suspect these could/should be tracked and emitted fully (in bulk) when a
> new data file is opened, so that each partial data file is fully
> consistent?
In my case I am not saving task events, but processing them. In Jiri's
case where events are written to a file it should be possible to stash
the unprocessed events on a list, when the exit happens move them to a
dead threads list which can be cleaned up from time to time and then on
file dump requests dump the task events followed by the sample events.
>
>> 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.
>
> Could this be used to emit currently relevant task context?
sure.
>
> Btw., I also think it would be useful to have kernel support for that -
> the 'collections' stuff I talked about a good while ago: the kernel would
> work with user-space to iterate over all MMAPs and all running COMMs at
> the opening of a tracing session.
>
> That way we could avoid racy access to /proc, we could make sure that all
> information that is emitted by FORK/COMM/MMAP is also emitted for the
> 'bulk' data, etc.
Walking the task list and emitting events would be better but wouldn't
that be a performance hit holding the task lock (tasklist_lock?)? (I
thought that one is needed when walking the task list.)
David
next prev parent reply other threads:[~2013-09-10 17:29 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
2013-09-14 18:32 ` David Ahern
2013-09-09 16:06 ` Ingo Molnar
2013-09-10 17:29 ` David Ahern [this message]
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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