Re: [PATCH] perf: ARM: Record the user-mode PC in the call chain.

From: Will Deacon
Date: Thu Jun 20 2013 - 05:08:31 EST

On Thu, Jun 20, 2013 at 04:17:06AM +0100, Jed Davis wrote:
> 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).

Wow, I didn't expect you to test it. Thanks!

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

I can extract some hardware from the pile in the corner of my flat if you
want a hand with testing.

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