From: Ingo Molnar <mingo@elte.hu>
To: Theodore Tso <tytso@MIT.EDU>
Cc: Frederic Weisbecker <fweisbec@gmail.com>, Jan Kara <jack@suse.cz>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Li Zefan <lizf@cn.fujitsu.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Masami Hiramatsu <mhiramat@redhat.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/18] Allow different tracers to be compiled independently
Date: Tue, 23 Mar 2010 09:05:26 +0100 [thread overview]
Message-ID: <20100323080526.GB4848@elte.hu> (raw)
In-Reply-To: <DA3F0457-83D6-4A95-AC86-188BC1C9B2F0@mit.edu>
* Theodore Tso <tytso@MIT.EDU> wrote:
>
> On Mar 22, 2010, at 9:04 PM, Frederic Weisbecker wrote:
> >
> > I don't know. Yeah this first looks like a good idea but once
> > CONFIG_EVENT_TRACING is enabled, each tracepoint is a lightweight thing
> > and induce a tiny overhead, probably hard to notice, and this is going to
> > be even more the case after the jmp label optimization patches.
> >
> > I liked the fact we had a general tracing kernel once the above config is
> > selected. And we don't bother telling people that to use tool X you need
> > CONFIG_EVENT_Y, and you need to rebuild your kernel, etc...
>
> Indeed, a lot of the value of tracepoints goes away if people are compiling
> kernels without them and we need to get a special "tracing kernel" installed
> before we can debug a problem.
>
> So I'd hope we can do the necessary optimization work so people don't feel
> it's necessary to enable or disable tracepoints by subsystem....
Yeah, agreed. Ultra-embedded can disable them all, but other than that i think
we should not make it too finegrained as a lot of tooling value is in the
'critical mass' that tracepoints have achieved. The power events tracepoints
are most useful when combined with scheduling events, etc.
Ingo
next prev parent reply other threads:[~2010-03-23 8:05 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-23 0:32 Jan Kara
2010-03-23 0:32 ` [PATCH 01/18] trace: Allow <linux/tracepoint.h> to create empty tracepoints Jan Kara
2010-03-23 1:06 ` Steven Rostedt
2010-03-26 1:30 ` Jan Kara
2010-03-23 0:32 ` [PATCH 02/18] block: Generate blktrace trace points only if blktrace is enabled Jan Kara
2010-03-23 0:32 ` [PATCH 03/18] mm: Generate kmemtrace trace points only if they are enabled Jan Kara
2010-03-23 0:32 ` [PATCH 04/18] mac80211: Generate trace points only if api tracer enabled Jan Kara
2010-03-23 1:11 ` Johannes Berg
2010-03-23 23:54 ` Steven Rostedt
2010-03-23 0:32 ` [PATCH 05/18] workqueue: Generate trace points only when workqueue " Jan Kara
2010-03-23 0:32 ` [PATCH 06/18] sched: Generate trace points only if scheduler tracing is enabled Jan Kara
2010-03-23 1:07 ` Frederic Weisbecker
2010-03-23 23:52 ` Steven Rostedt
2010-03-24 0:31 ` Frederic Weisbecker
2010-03-23 0:32 ` [PATCH 07/18] ext4: Provide config options for enabling ext4 and jbd2 tracing Jan Kara
2010-03-23 0:32 ` [PATCH 08/18] lockdep: Provide config option for enabling lock tracepoints Jan Kara
2010-03-23 0:32 ` [PATCH 09/18] module: Provide config option to enable tracing of module load / unload Jan Kara
2010-03-23 0:32 ` [PATCH 10/18] gfs2: Provide config option for enabling trace points Jan Kara
2010-03-23 12:01 ` [Cluster-devel] " Steven Whitehouse
2010-03-23 23:56 ` Steven Rostedt
2010-03-24 11:20 ` Steven Whitehouse
2010-03-24 12:09 ` Steven Rostedt
2010-03-23 0:32 ` [PATCH 11/18] i915: Provide config option for enabling tracepoints Jan Kara
2010-03-23 8:42 ` Chris Wilson
2010-03-23 0:32 ` [PATCH 12/18] timer: Provide config option for enabling timer tracepoints Jan Kara
2010-03-23 2:01 ` Thomas Gleixner
2010-03-23 3:01 ` Steven Rostedt
2010-03-23 0:32 ` [PATCH 13/18] acpi: Provide config option to enable power tracepoints Jan Kara
2010-03-23 0:32 ` [PATCH 14/18] net: Provide config option for enabling SKB tracing Jan Kara
2010-03-23 0:32 ` [PATCH 15/18] net: Provide config option for enabling NAPI tracing Jan Kara
2010-03-23 0:32 ` [PATCH 16/18] Generate empty tracepoints if syscall tracing is disabled Jan Kara
2010-03-23 0:32 ` [PATCH 17/18] kvm: Provide config option for enabling KVM trace events Jan Kara
2010-03-23 0:32 ` [PATCH 18/18] Create config option for enabling IRQ tracepoints Jan Kara
2010-03-23 1:04 ` [PATCH 0/18] Allow different tracers to be compiled independently Frederic Weisbecker
2010-03-23 3:34 ` Theodore Tso
2010-03-23 8:05 ` Ingo Molnar [this message]
2010-03-23 12:27 ` Mathieu Desnoyers
2010-03-23 13:18 ` Steven Rostedt
2010-03-26 0:20 ` Jan Kara
2010-03-26 19:09 ` Frederic Weisbecker
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