linux-kernel - Re: [PATCH 3/6] perf: Add timestamp to COMM and MMAP events

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Message-ID: <1291031690.32004.20.camel@laptop>
Date:	Mon, 29 Nov 2010 12:54:50 +0100
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Ian Munsie <imunsie@....ibm.com>
Cc:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Paul Mackerras <paulus@...ba.org>, Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH 3/6] perf: Add timestamp to COMM and MMAP events

On Mon, 2010-11-29 at 17:06 +1100, Ian Munsie wrote:
> 
> 
> This goes away if PERF_SAMPLE_CPU is added to the mix so that the
> timestamps are offset from the first event of *their* CPU, otherwise
> time-epoch can go negative, as it has done here. 

How does that happen, I though the power7 sched_clock() was fully
synchronized and monotonic across all cores?
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