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From: Andi Kleen <andi@firstfloor.org>
To: Jim Keniston <jkenisto@us.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	ananth@in.ibm.com, akpm@linux-foundation.org,
	lkml <linux-kernel@vger.kernel.org>,
	mingo@elte.hu, mhiramat@redhat.com, davem@davemloft.net,
	hskinnemoen@atmel.com
Subject: Re: [PATCH] Kprobes: Add kprobes smoke tests that run on boot
Date: Wed, 9 Jan 2008 22:21:03 +0100	[thread overview]
Message-ID: <20080109212103.GB15612@one.firstfloor.org> (raw)
In-Reply-To: <1199910240.4162.31.camel@dyn9047018096.beaverton.ibm.com>

On Wed, Jan 09, 2008 at 12:24:00PM -0800, Jim Keniston wrote:
> On Wed, 2008-01-09 at 00:28 +0100, Andi Kleen wrote:
> > > I have no problem with that, but if we want to make it buildable as a
> > > module, the call to get_kprobe() needs to be replaced with some other
> > > gcc-inline-defeating mechanism, or we need to export get_probe().  I
> > 
> > It's still unclear where noinline does not work (do you have details on that? 
> > It sounds a little dubious) ...
> 
> Here's a simplified version of a module we've used to gauge kprobes
> performance.  On my system (i386, 2.6.23-rc8 at the moment, gcc version
> 4.1.2), the module calls the (empty) probed function (probeme) niter
> times, but reports zero probe hits -- indicating probeme was inlined
> even though it was declared noinline.

Yes indeed looks like a gcc bug. Have you reported it?

-Andi

  reply	other threads:[~2008-01-09 21:18 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-08  6:33 [PATCH] Kprobes: Add kprobes smoke tests that run on boot Ananth N Mavinakayanahalli
2008-01-08  9:15 ` Ingo Molnar
2008-01-08 21:00 ` Andi Kleen
2008-01-08 22:18   ` Ingo Molnar
2008-01-08 22:49     ` Andi Kleen
2008-01-08 22:50       ` Ingo Molnar
2008-01-09  8:00     ` Christoph Hellwig
2008-01-09  8:08       ` Sam Ravnborg
2008-01-08 23:10   ` Jim Keniston
2008-01-08 23:28     ` Andi Kleen
2008-01-09 20:24       ` Jim Keniston
2008-01-09 21:21         ` Andi Kleen [this message]
2008-01-09 22:33           ` Jim Keniston
2008-01-09  7:43 ` David Miller

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