From: Mathieu Desnoyers <compudj@krystal.dyndns.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: prasad@linux.vnet.ibm.com, jan.kiszka@web.de,
Gian Lorenzo Meocci <glmeocci@gmail.com>,
ltt-dev@lists.casi.polymtl.ca, linux-kernel@vger.kernel.org,
mbligh@google.com
Subject: Re: [ltt-dev] trace a futex
Date: Fri, 5 Dec 2008 07:28:22 -0500 [thread overview]
Message-ID: <20081205122822.GA25816@Krystal> (raw)
In-Reply-To: <1228380784.5092.18.camel@twins>
* Peter Zijlstra (peterz@infradead.org) wrote:
>
> FWIW, the ftrace infrastructure has on many an occasion (even before it
> was called ftrace and specific to -rt) helped in debugging and fixing
> futex races.
>
Hrm, I'm not sure futex races is the key aspect of interest here.
Knowing which amount of pthread mutex lock calls ends up calling the
scheduler looks a bit more like the topic brought by this particular
use-case. Therefore, correlating the information from the nptl with the
kernel information would be useful.
Is lockdep called when a futex is taken ? Should we add instrumentation
(tracepoints) to futex.c ? If yes, was there specific instrumentation
you used with ftrace that should be added ?
Mathieu
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
next prev parent reply other threads:[~2008-12-05 12:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <8d94e9280812021142j2eb5ca72td730410e97ccd9a1@mail.gmail.com>
[not found] ` <20081202195015.GA25792@Krystal>
[not found] ` <8d94e9280812021215m6a63d6c2l4e64acd26274953d@mail.gmail.com>
[not found] ` <20081202215519.GA734@Krystal>
[not found] ` <4935B25F.7010701@web.de>
2008-12-03 5:26 ` [ltt-dev] trace a futex Mathieu Desnoyers
2008-12-03 18:01 ` K.Prasad
2008-12-04 8:53 ` Peter Zijlstra
2008-12-05 12:28 ` Mathieu Desnoyers [this message]
2008-12-05 15:58 ` Peter Zijlstra
2008-12-05 16:01 ` Peter Zijlstra
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=20081205122822.GA25816@Krystal \
--to=compudj@krystal.dyndns.org \
--cc=glmeocci@gmail.com \
--cc=jan.kiszka@web.de \
--cc=linux-kernel@vger.kernel.org \
--cc=ltt-dev@lists.casi.polymtl.ca \
--cc=mbligh@google.com \
--cc=peterz@infradead.org \
--cc=prasad@linux.vnet.ibm.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.