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Subject: Re: [PATCH][GIT PULL] powerpc64/tracing: Add frame buffer to calls
 of trace_hardirqs_on/off
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
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Date: Tue, 28 Dec 2010 08:38:37 +1100
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On Sat, 2010-12-25 at 16:04 -0500, Steven Rostedt wrote:
> 
> Note, when CONFIG_IRQSOFF_TRACE is set, there's already a bit of
> overhead :-)
> 
> Anyway, I'll have to take a look at how the frame pointer is set up.
> Or
> we could also set up all stacks coming into the kernel to have a
> "dummy"
> frame pointer that wont hurt anything if we index into it.
> 
> Anyway, I'm off till the new year, so I'll worry about it then ;-)

Right, might be simpler to just make them loop back onto themselves or
something like that. I can have a look too if I get a chance.

Cheers,
Ben.