[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <48A5670C.2080805@novell.com>
Date: Fri, 15 Aug 2008 07:22:52 -0400
From: Gregory Haskins <ghaskins@...ell.com>
To: Ingo Molnar <mingo@...e.hu>
CC: Steven Rostedt <rostedt@...dmis.org>, linux-kernel@...r.kernel.org,
Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <peterz@...radead.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
David Miller <davem@...emloft.net>,
Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>,
Roland McGrath <roland@...hat.com>,
Ulrich Drepper <drepper@...hat.com>,
Rusty Russell <rusty@...tcorp.com.au>,
Jeremy Fitzhardinge <jeremy@...p.org>,
Arnaldo Carvalho de Melo <acme@...hat.com>,
"Luis Claudio R. Goncalves" <lclaudio@...g.org>,
Clark Williams <williams@...hat.com>,
Bruce Duncan <bwduncan@...il.com>,
Marcin Slusarz <marcin.slusarz@...il.com>,
Steven Rostedt <srostedt@...hat.com>
Subject: Re: [PATCH v2 0/6] ftrace: to kill a daemon (small updates)
(From the original mail)
Steven Rostedt wrote:
>
> Along came Gregory Haskins, who was bickering about having ftrace enabled
> on a production -rt kernel. I told him the reasons that this would be bad
> and then he started thinking out loud, and suggesting wild ideas, like
> patching gcc!
>
^^^^^^^^^^
Ingo Molnar wrote:
> Eventually gcc should be extended to provide a separate section for
> instrumentation patch sites, instead of us having to disassemble the
> object code.
:)
I obviously agree with this, so +1
Though, tbh, at the time I suggested it I didn't think of Steve's idea
to post-process which was quite clever. But I do agree that having gcc
do it will probably save some build time since it will probably be
trivial for it to do this when already processing -pg. It would have the
added benefit of letting the arch specific toolchain do the arch
specific work (though I think Steve's solution capitalizes on the
toolchain extensively as it is).
The biggest downside is that we would have an external dependency on gcc
for the feature, but I guess the kernel already has some of those anyway
(e.g. the stack overflow guard feature, etc). We could always fall back
on Steve's post-processing if the toolchain lacks the feature.
-Greg
Download attachment "signature.asc" of type "application/pgp-signature" (258 bytes)
Powered by blists - more mailing lists