From: Mathieu Desnoyers <compudj@krystal.dyndns.org>
To: Darren Hart <darren@dvhart.com>
Cc: Roland Dreier <rdreier@cisco.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Masami Hiramatsu <mhiramat@redhat.com>,
Martin Bligh <mbligh@google.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
"Frank Ch. Eigler" <fche@redhat.com>,
systemtap-ml <systemtap@sources.redhat.com>
Subject: Re: Unified tracing buffer
Date: Mon, 22 Sep 2008 22:31:15 -0400 [thread overview]
Message-ID: <20080923023115.GE24937@Krystal> (raw)
In-Reply-To: <e17d46420809221926g1396fbb4id5b9c934bad1d96e@mail.gmail.com>
* Darren Hart (darren@dvhart.com) wrote:
> On Mon, Sep 22, 2008 at 7:02 PM, Mathieu Desnoyers <compudj@krystal.dyndns.org>
> > So only in the specific case of instrumentation of things like locking,
> > where it is possible to insure that instrumentation is synchronized with
> > the instrumented operation, does it make a difference to choose the TSC
> > (which implies a slight delta between the TSCs due to cache line delays
> > at synchronization and delay due to TSCs drifts caused by temperature)
> > over an atomic increment.
> >
>
> Hrm, i think that overlooks the other reason to use a time based counter over
> an atomic increment: you might care about time. Perhaps one might be less
> concerned with actual order tightly grouped events and more concerned with the
> actual time delta between more temporally distant events. In that case, using
> a clocksource would still be valuable. Although admitedtly the caller could
> embed that in their payload, but since we seem to agree we need some kind of
> counter, the time-based counter appears to be the most flexible.
>
> Thanks,
>
See my answer to Linus for a proposal on how to do both :)
Mathieu
> --
> Darren Hart
>
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
next prev parent reply other threads:[~2008-09-23 2:31 UTC|newest]
Thread overview: 125+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-19 21:33 Unified tracing buffer Martin Bligh
2008-09-19 21:42 ` Randy Dunlap
2008-09-19 21:57 ` Martin Bligh
2008-09-19 22:41 ` Olaf Dabrunz
2008-09-19 22:19 ` Martin Bligh
2008-09-20 8:10 ` Olaf Dabrunz
2008-09-20 8:29 ` Steven Rostedt
2008-09-20 11:40 ` Mathieu Desnoyers
2008-09-20 8:26 ` Steven Rostedt
2008-09-20 11:44 ` Mathieu Desnoyers
2008-09-19 22:28 ` Olaf Dabrunz
2008-09-19 22:09 ` Martin Bligh
2008-09-19 23:18 ` Frank Ch. Eigler
2008-09-20 8:50 ` Steven Rostedt
2008-09-20 13:37 ` Mathieu Desnoyers
2008-09-20 13:51 ` Steven Rostedt
2008-09-20 14:54 ` Steven Rostedt
2008-09-22 18:45 ` Mathieu Desnoyers
2008-09-22 21:39 ` Steven Rostedt
2008-09-23 3:27 ` Mathieu Desnoyers
2008-09-20 0:07 ` Peter Zijlstra
2008-09-22 14:07 ` K.Prasad
2008-09-22 14:45 ` Peter Zijlstra
2008-09-22 16:29 ` Martin Bligh
2008-09-22 16:36 ` Peter Zijlstra
2008-09-22 20:50 ` Masami Hiramatsu
2008-09-23 3:05 ` Mathieu Desnoyers
2008-09-23 2:49 ` Mathieu Desnoyers
2008-09-23 5:25 ` Tom Zanussi
2008-09-23 9:31 ` Peter Zijlstra
2008-09-23 18:13 ` Mathieu Desnoyers
2008-09-23 18:13 ` Mathieu Desnoyers
2008-09-23 18:33 ` Christoph Lameter
2008-09-23 18:33 ` Christoph Lameter
2008-09-23 18:56 ` Linus Torvalds
2008-09-23 18:56 ` Linus Torvalds
2008-09-23 13:50 ` Mathieu Desnoyers
2008-09-23 14:00 ` Martin Bligh
2008-09-23 17:55 ` K.Prasad
2008-09-23 18:27 ` Martin Bligh
2008-09-24 3:50 ` Tom Zanussi
2008-09-24 5:42 ` K.Prasad
2008-09-25 6:07 ` [RFC PATCH 0/8] current relay cleanup patchset Tom Zanussi
2008-09-25 6:07 ` [RFC PATCH 1/8] relay - Clean up relay_switch_subbuf() and make waking up consumers optional Tom Zanussi
2008-09-25 6:07 ` [RFC PATCH 2/8] relay - Make the relay sub-buffer switch code replaceable Tom Zanussi
2008-09-25 6:07 ` [RFC PATCH 3/8] relay - Add channel flags to relay, remove global callback param Tom Zanussi
2008-09-25 6:07 ` [RFC PATCH 4/8] relay - Add reserved param to switch-subbuf, in preparation for non-pad write/reserve Tom Zanussi
2008-09-25 6:07 ` [RFC PATCH 5/8] relay - Map the first sub-buffer at the end of the buffer, for temporary convenience Tom Zanussi
2008-09-25 6:07 ` [RFC PATCH 6/8] relay - Replace relay_reserve/relay_write with non-padded versions Tom Zanussi
2008-09-25 6:07 ` [RFC PATCH 7/8] relay - Remove padding-related code from relay_read()/relay_splice_read() et al Tom Zanussi
2008-09-25 6:08 ` [RFC PATCH 8/8] relay - Clean up remaining padding-related junk Tom Zanussi
2008-09-23 5:27 ` [PATCH 1/3] relay - clean up subbuf switch Tom Zanussi
2008-09-23 20:15 ` Andrew Morton
2008-09-23 5:27 ` [PATCH 2/3] relay - make subbuf switch replaceable Tom Zanussi
2008-09-23 20:17 ` Andrew Morton
2008-09-23 5:27 ` [PATCH 3/3] relay - add channel flags Tom Zanussi
2008-09-23 20:20 ` Andrew Morton
2008-09-24 3:57 ` Tom Zanussi
2008-09-20 0:26 ` Unified tracing buffer Marcel Holtmann
2008-09-20 9:03 ` Steven Rostedt
2008-09-20 13:55 ` Mathieu Desnoyers
2008-09-20 14:12 ` Arjan van de Ven
2008-09-22 18:52 ` Mathieu Desnoyers
2008-10-02 15:28 ` Jason Baron
2008-10-03 16:11 ` Mathieu Desnoyers
2008-10-03 18:37 ` Jason Baron
2008-10-03 19:10 ` Mathieu Desnoyers
2008-10-03 19:25 ` Jason Baron
2008-10-03 19:56 ` Mathieu Desnoyers
2008-10-03 20:25 ` Jason Baron
2008-10-03 21:52 ` Frank Ch. Eigler
2008-09-22 3:09 ` KOSAKI Motohiro
2008-09-22 9:57 ` Peter Zijlstra
2008-09-23 2:36 ` Mathieu Desnoyers
2008-09-22 13:57 ` K.Prasad
2008-09-22 19:45 ` Masami Hiramatsu
2008-09-22 20:13 ` Martin Bligh
2008-09-22 22:25 ` Masami Hiramatsu
2008-09-22 23:11 ` Darren Hart
2008-09-23 0:04 ` Masami Hiramatsu
2008-09-22 23:16 ` Martin Bligh
2008-09-23 0:05 ` Masami Hiramatsu
2008-09-23 0:12 ` Martin Bligh
2008-09-23 14:49 ` Masami Hiramatsu
2008-09-23 15:04 ` Mathieu Desnoyers
2008-09-23 15:30 ` Masami Hiramatsu
2008-09-23 16:01 ` Linus Torvalds
2008-09-23 17:04 ` Masami Hiramatsu
2008-09-23 17:30 ` Thomas Gleixner
2008-09-23 18:59 ` Masami Hiramatsu
2008-09-23 19:36 ` Thomas Gleixner
2008-09-23 19:38 ` Martin Bligh
2008-09-23 19:41 ` Thomas Gleixner
2008-09-23 19:50 ` Martin Bligh
2008-09-23 20:03 ` Thomas Gleixner
2008-09-23 21:02 ` Martin Bligh
2008-09-23 20:03 ` Masami Hiramatsu
2008-09-23 20:08 ` Thomas Gleixner
2008-09-23 15:46 ` Linus Torvalds
2008-09-23 0:39 ` Linus Torvalds
2008-09-23 1:26 ` Roland Dreier
2008-09-23 1:39 ` Steven Rostedt
2008-09-23 2:02 ` Mathieu Desnoyers
2008-09-23 2:26 ` Darren Hart
2008-09-23 2:31 ` Mathieu Desnoyers [this message]
2008-09-23 3:26 ` Linus Torvalds
2008-09-23 3:36 ` Mathieu Desnoyers
2008-09-23 4:05 ` Linus Torvalds
2008-09-23 3:43 ` Steven Rostedt
2008-09-23 4:10 ` Masami Hiramatsu
2008-09-23 4:17 ` Martin Bligh
2008-09-23 15:23 ` Masami Hiramatsu
2008-09-23 10:53 ` Steven Rostedt
2008-09-23 4:19 ` Linus Torvalds
2008-09-23 14:12 ` Mathieu Desnoyers
2008-09-23 2:30 ` Mathieu Desnoyers
2008-09-23 3:06 ` Masami Hiramatsu
2008-09-23 14:36 ` KOSAKI Motohiro
2008-09-23 15:02 ` Frank Ch. Eigler
2008-09-23 15:21 ` Masami Hiramatsu
2008-09-23 17:59 ` KOSAKI Motohiro
2008-09-23 18:28 ` Martin Bligh
2008-09-23 3:33 ` Andi Kleen
2008-09-23 3:47 ` Martin Bligh
2008-09-23 5:04 ` Andi Kleen
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