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Date: Fri, 10 Jul 2009 15:27:15 +0300
From: Andriy Gapon <avg@freebsd.org>
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To: Andrew Brampton <brampton+freebsd@gmail.com>
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Cc: freebsd-current@freebsd.org
Subject: Re: dtrace users opinion solicited (timestamps)
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on 10/07/2009 01:02 Andrew Brampton said the following:
> According to wikipedia newer Intel processors have a constant rate TSC
> whos freq does not change. If this features is available on most
> processors today, then I am happy to stick with option 1.
> 
> Another problem with this is that on a multicore machine each core may
> have different TSC values. Has anyone thought how to address this
> issue? Could we calculate the offset of each core from core0, and then
> ensure the offset is applied to the tsc value when it is needed?

Yes. The actual code accounts for inter-CPU/core TSC skew.

-- 
Andriy Gapon