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From: Nelson Elhage <nelhage@nelhage.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@elte.hu>,
	Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 0/3] perf: builtin-record: Be more helpful when running up against mlock limits.
Date: Mon, 19 Dec 2011 08:39:29 -0500	[thread overview]
Message-ID: <1324301972-22740-1-git-send-email-nelhage@nelhage.com> (raw)

With the current code, it's relatively easy to run up against the
perf_event_mlock_kb limit if you try to attach to a multithreaded
target with 'perf record -p', because perf will attempt to mmap 512k
per target thread, and the default mlock limit is (512k + 1 page),
total.

Current, this results in a completely inscrutable
  Fatal: failed to mmap with 22 (Invalid argument)

We should perhaps automatically detect a better choice of mmap_pages,
but in the meanwhile, it's easy to improve the error to give users
some guidance about what's going on, so that hopefully I can be the
last person to have to source-dive to figure out what's going on.


             reply	other threads:[~2011-12-19 13:40 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-19 13:39 Nelson Elhage [this message]
2011-12-19 13:39 ` [PATCH 1/3] perf: __perf_evlist__mmap: Fix errno value on failed map Nelson Elhage
2011-12-19 15:33   ` Namhyung Kim
2011-12-19 16:29     ` Arnaldo Carvalho de Melo
2011-12-20 17:55     ` Arnaldo Carvalho de Melo
2011-12-21  8:43   ` [tip:perf/core] perf evlist: Fix errno value reporting on failed mmap tip-bot for Nelson Elhage
2011-12-19 13:39 ` [PATCH 2/3] perf: builtin-record: Provide advice if mmap'ing fails with EPERM Nelson Elhage
2011-12-29 20:50   ` [tip:perf/core] perf: builtin-record: Provide advice if mmap' ing " tip-bot for Nelson Elhage
2011-12-19 13:39 ` [PATCH 3/3] perf: builtin-record: Document and check that mmap_pages must be a power of two Nelson Elhage
2011-12-29 20:50   ` [tip:perf/core] " tip-bot for Nelson Elhage

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