From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>,
Ingo Molnar <mingo@elte.hu>, Paul Mackerras <paulus@samba.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: Lock dependency based tree report in perf lock
Date: Mon, 01 Feb 2010 09:25:04 +0100 [thread overview]
Message-ID: <1265012704.24455.80.camel@laptop> (raw)
In-Reply-To: <20100130185736.GC5675@nowhere>
On Sat, 2010-01-30 at 19:57 +0100, Frederic Weisbecker wrote:
> On Sat, Jan 30, 2010 at 09:46:28AM +0100, Peter Zijlstra wrote:
> > On Sat, 2010-01-30 at 00:17 +0100, Frederic Weisbecker wrote:
> > >
> > >
> > > Anyway, that's just an idea, not trivial I must admit.
> >
> > lockdep actually collects all this information, so writing it out isn't
> > too hard.
>
>
>
> Lockdep collects the theorical dependencies but not the practical
> scenarios.
>
> Say B and C depend on A, you'll get:
>
> A
> / \
> B C
>
> But nothing can tell you that if A is taken, B and C will always
> be taken. You may have different scenarios based on this dependency,
> which is not something that lockdep logs, right?
Right. But we keep track of the full held lock stack, which is what was
requested.
next prev parent reply other threads:[~2010-02-01 8:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-29 23:17 Lock dependency based tree report in perf lock Frederic Weisbecker
2010-01-30 8:46 ` Peter Zijlstra
2010-01-30 18:57 ` Frederic Weisbecker
2010-02-01 8:25 ` Peter Zijlstra [this message]
2010-02-01 17:48 ` Frederic Weisbecker
2010-02-01 1:23 ` Frederic Weisbecker
2010-02-01 9:21 ` 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=1265012704.24455.80.camel@laptop \
--to=peterz@infradead.org \
--cc=acme@redhat.com \
--cc=fweisbec@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=mitake@dcl.info.waseda.ac.jp \
--cc=paulmck@linux.vnet.ibm.com \
--cc=paulus@samba.org \
--cc=tglx@linutronix.de \
/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.