From: David Ahern <dsahern@gmail.com>
To: Namhyung Kim <namhyung@kernel.org>, Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
linux-kernel@vger.kernel.org, jolsa@redhat.com,
Frederic Weisbecker <fweisbec@gmail.com>,
Mike Galbraith <efault@gmx.de>,
Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 4/5] perf record: mmap output file - v5
Date: Mon, 18 Nov 2013 17:34:49 -0700 [thread overview]
Message-ID: <528AB229.6030603@gmail.com> (raw)
In-Reply-To: <877gc5utkf.fsf@sejong.aot.lge.com>
On 11/18/13, 5:24 PM, Namhyung Kim wrote:
>>>> What now? Can we add the mmap path as an option?
>>>
>>> I'd say an option is always a possibility, but someone please try
>>> what happens if you use stupid large events (dwarf stack copies) on
>>> PERF_COUNT_SW_PAGE_FAULTS (.period=1) while recording with mmap().
>>>
>>> The other option is to simply disallow PERF_SAMPLE_STACK_USER for
>>> that event.
>>>
>>> Personally I think 8k copies for every event are way stupid anyway,
>>> that's a metric ton of data at a huge cost.
>>
>> Well, with 1 khz sampling of a single threaded workload it's 8MB per
>> second - that's 80 MB for 10 seconds profiling - not the end of the
>> world.
>
> We now use 4 khz sampling frequency by default, just FYI. :)
I think Peter is asking about:
perf record -e faults -c 1 --call-graph dwarf,8192 -a -- sleep 1
And as expected it is a massive feedback spiraling out of control.
David
next prev parent reply other threads:[~2013-11-19 0:34 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-12 14:46 [PATCH 0/5] perf record: mmap output file - v5 David Ahern
2013-11-12 14:46 ` [PATCH 1/5] perf record: Fix segfault with --no-mmap-pages David Ahern
2013-11-12 21:57 ` [tip:perf/urgent] " tip-bot for David Ahern
2013-11-12 14:46 ` [PATCH 2/5] perf tool: Round mmap pages to power 2 - v2 David Ahern
2013-11-12 21:57 ` [tip:perf/urgent] perf evlist: " tip-bot for David Ahern
2013-11-12 14:46 ` [PATCH 3/5] perf tool: Refactor mmap_pages parsing David Ahern
2013-11-12 21:57 ` [tip:perf/urgent] perf evlist: " tip-bot for David Ahern
2013-11-12 14:46 ` [PATCH 4/5] perf record: mmap output file - v5 David Ahern
2013-11-12 14:57 ` Peter Zijlstra
2013-11-12 15:07 ` Arnaldo Carvalho de Melo
2013-11-12 15:19 ` Peter Zijlstra
2013-11-12 15:36 ` David Ahern
2013-11-12 21:11 ` Ingo Molnar
2013-11-13 11:34 ` Peter Zijlstra
2013-11-13 11:50 ` Ingo Molnar
2013-11-13 12:16 ` Peter Zijlstra
2013-11-13 14:29 ` David Ahern
2013-11-15 16:41 ` David Ahern
2013-11-18 9:01 ` Peter Zijlstra
2013-11-18 9:40 ` Ingo Molnar
2013-11-19 0:24 ` Namhyung Kim
2013-11-19 0:34 ` David Ahern [this message]
2013-11-19 1:48 ` Namhyung Kim
2013-11-19 2:02 ` Namhyung Kim
2013-11-19 2:13 ` Namhyung Kim
2013-11-19 2:17 ` David Ahern
2013-11-19 2:30 ` Namhyung Kim
2013-11-19 2:33 ` David Ahern
2013-11-19 2:36 ` Namhyung Kim
2013-11-19 6:58 ` Ingo Molnar
2013-11-19 11:48 ` Peter Zijlstra
2013-11-19 11:49 ` Peter Zijlstra
2013-11-19 13:13 ` Ingo Molnar
2013-11-19 13:45 ` Peter Zijlstra
2013-11-19 15:31 ` Ingo Molnar
2013-11-19 16:09 ` David Ahern
2013-11-19 16:14 ` Ingo Molnar
2013-11-19 12:08 ` Peter Zijlstra
2013-11-19 6:54 ` Ingo Molnar
2013-11-12 14:46 ` [PATCH 5/5] perf record: Handle out of space failures writing data with mmap David Ahern
2013-11-12 21:19 ` Ingo Molnar
2013-11-13 14:33 ` David Ahern
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=528AB229.6030603@gmail.com \
--to=dsahern@gmail.com \
--cc=acme@ghostprotocols.net \
--cc=efault@gmx.de \
--cc=eranian@google.com \
--cc=fweisbec@gmail.com \
--cc=jolsa@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=namhyung@kernel.org \
--cc=peterz@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).