Date: Wed, 19 Jun 2013 20:17:06 -0700
From: Jed Davis <jld@mozilla.com>
To: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>, Paul Mackerras <paulus@samba.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
        Russell King <linux@arm.linux.org.uk>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] perf: ARM: Record the user-mode PC in the call chain.
Message-ID: <20130620031706.GB27428@mozilla.com>
References: <20130613232111.GA12536@mozilla.com>
 <20130618131319.GC6801@mudshark.cambridge.arm.com>
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On Tue, Jun 18, 2013 at 02:13:19PM +0100, Will Deacon wrote:
> On Fri, Jun 14, 2013 at 12:21:11AM +0100, Jed Davis wrote:
> > With this change, we no longer lose the innermost entry in the user-mode
> > part of the call chain.  See also the x86 port, which includes the ip.
> > 
> > It's possible to partially work around this problem by post-processing
> > the data to use the PERF_SAMPLE_IP value, but this works only if the CPU
> > wasn't in the kernel when the sample was taken.
> 
> Thanks. I guess we need something similar for arm64 too. Could you cook a
> similar patch please?

Done (and tested, on the ARM V8 Foundation Model).

It looked as if the powerpc and sparc ports might have similar issues,
but I haven't checked on them yet.

--Jed

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