linux-kernel - Re: [PATCH 1/7] Simple Performance Counters: Core Piece

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Message-ID: <Pine.LNX.4.64.0708171340060.9404@schroedinger.engr.sgi.com>
Date:	Fri, 17 Aug 2007 13:42:00 -0700 (PDT)
From:	Christoph Lameter <clameter@....com>
To:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/7] Simple Performance Counters: Core Piece

On Fri, 17 Aug 2007, Mathieu Desnoyers wrote:

> Actually, get_cycles() at least on some AMD cpus, do not synchronize the
> core, which can skew the results. You might want to use
> get_cycles_sync() there.

get_cycle() results as used here are bound to a single processor. If we 
end up on a different processor at the end of the measurement then the 
result is discarded. So not need for get_cycles_sync.

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