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Date: Thu, 5 Dec 2002 03:14:43 -0800
From: William Lee Irwin III <wli@holomorphy.com>
To: Erich Focht <efocht@ess.nec.de>
Cc: Andrew Morton <akpm@digeo.com>,
       linux-kernel <linux-kernel@vger.kernel.org>,
       Michael Hohnbaum <hohnbaum@us.ibm.com>,
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Subject: Re: per cpu time statistics
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References: <200212041343.39734.efocht@ess.nec.de> <3DEE3FAE.558649F5@digeo.com> <200212051157.29775.efocht@ess.nec.de>
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On Thu, Dec 05, 2002 at 11:57:29AM +0100, Erich Focht wrote:
> My patch is basically the reverting patch plus changed ifdefs and a
> bunch of Kconfig entries. I'd be happy to get this feature back, no
> matter how it is implemented. I think it is necessary for performance
> analysis on HT, NUMA, SMT systems.

32-bit is not irrelevant, but there's certainly a 64-bit land where
the critical 32-bit correctness issue becomes a minor 64-bit
performance issue. This is the nature of extended 32-bit addressing.
By and large what is a severe and world-breaking correctness issue for
32-bit with extended addressing is a performance issue for the rest.

And so I feel we are all in harmony; the scheduler statistics are in
fact valuable on all platforms, it's just an question of basic "should
this overhead be required or optional?"


Bill
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