From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Jamie Iles <jamie@jamieiles.com>
Cc: Ming Lei <tom.leiming@gmail.com>,
Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@elte.hu>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Russell King <linux@arm.linux.org.uk>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [Questions] How to run 'perf top' on ARM to profile kernel functions with modules loaded
Date: Thu, 11 Nov 2010 13:06:16 +0100 [thread overview]
Message-ID: <1289477176.2084.64.camel@laptop> (raw)
In-Reply-To: <20101111091733.GA2929@pulham.picochip.com>
On Thu, 2010-11-11 at 09:17 +0000, Jamie Iles wrote:
> On Thu, Nov 11, 2010 at 03:52:07PM +0800, Ming Lei wrote:
> > 2010/11/11 Ming Lei <tom.leiming@gmail.com>:
> > > Hi,
> > >
> > > 'perf top' can't display any functions when modules are loaded on ARM.
> >
> > Sorry, should be can't display any kernel functions when modules are loaded
> > on ARM.
> I've noticed this myself and I spent a bit of time looking into it last week
> but didn't get too far. I did wonder if it was something to do with the map
> fixups after loading the modules. If you look at the raw events after a perf
> record with 'perf report -D' then the last module has a size that takes it to
> 0xFFFFFFFF which overlaps with the rest of the kernel symbols.
>
> On x86 it looks like the modules are loaded after the kernel image in VM
> unlike ARM.
Order shouldn't matter, but that overlap is very likely what kills it.
That module size is buggy.
next prev parent reply other threads:[~2010-11-11 12:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-11 6:56 [Questions] How to run 'perf top' on ARM to profile kernel functions with modules loaded Ming Lei
2010-11-11 7:52 ` Ming Lei
2010-11-11 8:28 ` Ingo Molnar
2010-11-11 8:34 ` Kyungmin Park
2010-11-11 10:03 ` Ming Lei
2010-11-11 9:17 ` Jamie Iles
2010-11-11 12:06 ` Peter Zijlstra [this message]
2010-11-11 12:21 ` Jamie Iles
2010-11-11 12:30 ` Peter Zijlstra
2010-11-12 1:40 ` Ming Lei
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