From: David Ahern <dsahern@gmail.com>
To: Mikolaj Konarski <mikolaj.konarski@gmail.com>
Cc: chenggang.qin@gmail.com, Bernie Pope <florbitous@gmail.com>,
Duncan Coutts <duncan@well-typed.com>,
linux-perf-users@vger.kernel.org
Subject: Re: How to trace threads created by a process after perf has started recording, using the -p PID flag?
Date: Tue, 04 Sep 2012 10:04:31 -0600 [thread overview]
Message-ID: <5046268F.4050504@gmail.com> (raw)
In-Reply-To: <CAHFo2up0cy4A8pSX5=dJ4k95ZtUTEzvzqcvfRoaoUjedpcvw5Q@mail.gmail.com>
On 9/3/12 4:17 PM, Mikolaj Konarski wrote:
>>> Could someone clarify the behaviour of the -p PID flag of perf-record?
>>> In our experiments (3.2.0-27 #43-Ubuntu SMP x86_64),
>>> it ignores events on threads spawned after perf-record is started.
>>> Is this the intended behaviour, and is there any work-around?
>
> Anybody? We'd love to use a proven, standard workaround
> for this issue, preferably without forcing our users to upgrade
> the kernel or wait for any future release. Do we even diagnose
> the problem correctly? The best workaround we can come up with
> right now is to use the "--filter 'pid==NNNN'" option, but it has
> a couple of downsides. Any help would be sincerely appreciated.
I see the problem now. The perf tool gets FORK events as threads are
created, but it does not respond to them and create new counters. Some
refactoring is needed to make that happen.
David
next prev parent reply other threads:[~2012-09-04 16:04 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-25 12:52 How to trace threads created by a process after perf has started recording, using the -p PID flag? Mikolaj Konarski
[not found] ` <CAKYOsXwF-Rk97BEWk_fEHhfVisPy_q439tdx7H9onAOyFi=-uA@mail.gmail.com>
2012-09-03 22:17 ` Mikolaj Konarski
2012-09-04 6:47 ` Namhyung Kim
2012-09-04 16:04 ` David Ahern [this message]
2012-09-22 7:58 ` Mikolaj Konarski
2012-09-22 18:39 ` David Ahern
2012-09-22 19:57 ` Mikolaj Konarski
2012-09-24 4:31 ` David Ahern
[not found] <CAJgLYc+dMADVBkbPq1wJFptcx63UUSg24DDM5BbYSWW2bDV+tg@mail.gmail.com>
2012-08-26 4:56 ` chenggang qin
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