From: Tim Bird <tim.bird@am.sony.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Christoph Hellwig <hch@infradead.org>,
Gregory Haskins <ghaskins@novell.com>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
Thomas Gleixner <tglx@linutronix.de>,
Sam Ravnborg <sam@ravnborg.org>,
"Frank Ch. Eigler" <fche@redhat.com>,
Steven Rostedt <srostedt@redhat.com>,
Paul Mackerras <paulus@samba.org>,
Daniel Walker <dwalker@mvista.com>
Subject: Re: [RFC PATCH 16/22 -v2] add get_monotonic_cycles
Date: Wed, 16 Jan 2008 10:01:34 -0800 [thread overview]
Message-ID: <478E467E.6030409@am.sony.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0801161041010.15998@gandalf.stny.rr.com>
Steven Rostedt wrote:
> grmble. Then how do you trace preempt_disable? As my tracer does that
> (see the last patch in the series).
One way is to make a tracer_preempt_disable() and tracer_preempt_enable(),
both of which would be 'notrace'. You could probably optimize them
as well. The standard preempt_disable and preempt_enable don't look
very efficient (e.g. what's up with converting an increment operation into
an addition? - gak!)
Any lock you do is going to have a pretty bad effect.
In order to be able to trace as much as possible, for KFT, I implemented
my own synchronization mechanism using cmpxchg, to avoid using any of the
existing kernel locks (which change more often than you'd think, and have
weird side effects).
=============================
Tim Bird
Architecture Group Chair, CE Linux Forum
Senior Staff Engineer, Sony Corporation of America
=============================
next prev parent reply other threads:[~2008-01-16 17:58 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-09 23:29 [RFC PATCH 00/22 -v2] mcount and latency tracing utility -v2 Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 01/22 -v2] Add basic support for gcc profiler instrumentation Steven Rostedt
2008-01-10 18:19 ` Jan Kiszka
2008-01-10 19:54 ` Steven Rostedt
2008-01-10 23:02 ` Steven Rostedt
2008-01-10 18:28 ` Sam Ravnborg
2008-01-10 19:10 ` Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 02/22 -v2] Annotate core code that should not be traced Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 03/22 -v2] x86_64: notrace annotations Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 04/22 -v2] add notrace annotations to vsyscall Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 05/22 -v2] add notrace annotations for NMI routines Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 06/22 -v2] mcount based trace in the form of a header file library Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 07/22 -v2] tracer add debugfs interface Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 08/22 -v2] mcount tracer output file Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 09/22 -v2] mcount tracer show task comm and pid Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 10/22 -v2] Add a symbol only trace output Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 11/22 -v2] Reset the tracer when started Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 12/22 -v2] separate out the percpu date into a percpu struct Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 13/22 -v2] handle accurate time keeping over long delays Steven Rostedt
2008-01-10 0:00 ` john stultz
2008-01-10 0:09 ` Steven Rostedt
2008-01-10 19:54 ` Tony Luck
2008-01-10 20:15 ` Steven Rostedt
2008-01-10 20:41 ` john stultz
2008-01-10 20:29 ` john stultz
2008-01-10 20:42 ` Mathieu Desnoyers
2008-01-10 21:25 ` john stultz
2008-01-10 22:00 ` Mathieu Desnoyers
2008-01-10 22:40 ` Steven Rostedt
2008-01-10 22:51 ` john stultz
2008-01-10 23:05 ` john stultz
2008-01-10 21:33 ` [RFC PATCH 13/22 -v2] handle accurate time keeping over longdelays Luck, Tony
2008-01-10 0:19 ` [RFC PATCH 13/22 -v2] handle accurate time keeping over long delays john stultz
2008-01-10 0:25 ` Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 14/22 -v2] time keeping add cycle_raw for actual incrementation Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 15/22 -v2] initialize the clock source to jiffies clock Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 16/22 -v2] add get_monotonic_cycles Steven Rostedt
2008-01-10 3:28 ` Daniel Walker
2008-01-15 21:46 ` Mathieu Desnoyers
2008-01-15 22:01 ` Steven Rostedt
2008-01-15 22:03 ` Steven Rostedt
2008-01-15 22:08 ` Mathieu Desnoyers
2008-01-16 1:38 ` Steven Rostedt
2008-01-16 3:17 ` Mathieu Desnoyers
2008-01-16 13:17 ` Steven Rostedt
2008-01-16 14:56 ` Mathieu Desnoyers
2008-01-16 15:06 ` Steven Rostedt
2008-01-16 15:28 ` Mathieu Desnoyers
2008-01-16 15:58 ` Steven Rostedt
2008-01-16 17:00 ` Mathieu Desnoyers
2008-01-16 17:49 ` Mathieu Desnoyers
2008-01-16 19:43 ` Steven Rostedt
2008-01-16 20:17 ` Mathieu Desnoyers
2008-01-16 20:45 ` Tim Bird
2008-01-16 20:49 ` Steven Rostedt
2008-01-17 20:08 ` Steven Rostedt
2008-01-17 20:37 ` Frank Ch. Eigler
2008-01-17 21:03 ` Steven Rostedt
2008-01-18 22:26 ` Mathieu Desnoyers
2008-01-18 22:49 ` Steven Rostedt
2008-01-18 23:19 ` Mathieu Desnoyers
2008-01-19 3:36 ` Frank Ch. Eigler
2008-01-19 3:55 ` Steven Rostedt
2008-01-19 4:23 ` Frank Ch. Eigler
2008-01-19 15:29 ` Mathieu Desnoyers
2008-01-19 3:32 ` Frank Ch. Eigler
2008-01-16 18:01 ` Tim Bird [this message]
2008-01-16 22:36 ` john stultz
2008-01-16 22:51 ` john stultz
2008-01-16 23:33 ` Steven Rostedt
2008-01-17 2:28 ` john stultz
2008-01-17 2:40 ` Mathieu Desnoyers
2008-01-17 2:50 ` Mathieu Desnoyers
2008-01-17 3:02 ` Steven Rostedt
2008-01-17 3:21 ` Paul Mackerras
2008-01-17 3:39 ` Steven Rostedt
2008-01-17 4:22 ` Mathieu Desnoyers
2008-01-17 4:25 ` Mathieu Desnoyers
2008-01-17 4:14 ` Mathieu Desnoyers
2008-01-17 15:22 ` Steven Rostedt
2008-01-17 17:46 ` Linus Torvalds
2008-01-17 2:51 ` Steven Rostedt
2008-01-16 23:39 ` Mathieu Desnoyers
2008-01-16 23:50 ` Steven Rostedt
2008-01-17 0:36 ` Steven Rostedt
2008-01-17 0:33 ` john stultz
2008-01-17 2:20 ` Mathieu Desnoyers
2008-01-17 1:03 ` Linus Torvalds
2008-01-17 1:35 ` Mathieu Desnoyers
2008-01-17 2:20 ` john stultz
2008-01-17 2:35 ` Mathieu Desnoyers
2008-01-09 23:29 ` [RFC PATCH 17/22 -v2] Add timestamps to tracer Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 18/22 -v2] Sort trace by timestamp Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 19/22 -v2] speed up the output of the tracer Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 20/22 -v2] Add latency_trace format tor tracer Steven Rostedt
2008-01-10 3:41 ` Daniel Walker
2008-01-09 23:29 ` [RFC PATCH 21/22 -v2] Split out specific tracing functions Steven Rostedt
2008-01-09 23:29 ` [RFC PATCH 22/22 -v2] Trace irq disabled critical timings Steven Rostedt
2008-01-10 3:58 ` Daniel Walker
2008-01-10 14:45 ` Steven Rostedt
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