linux-kernel - Re: [RFC 4/4] cputime: remove scaling

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Message-ID: <5166D498.2090808@zytor.com>
Date:	Thu, 11 Apr 2013 08:19:52 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Stanislaw Gruszka <sgruszka@...hat.com>
CC:	Ingo Molnar <mingo@...nel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Peter Zijlstra <peterz@...radead.org>, rostedt@...dmis.org,
	akpm@...ux-foundation.org, tglx@...utronix.de,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [RFC 4/4] cputime: remove scaling

On 04/11/2013 01:37 AM, Stanislaw Gruszka wrote:
> On Wed, Apr 10, 2013 at 07:29:21AM -0700, H. Peter Anvin wrote:
>> I have a patch that does scaling by multiply for 64-bit architectures.  I probably should clean it up and send it in.  I need to see if it fixes this problem.
> Interesting. Could you attach draft patch, so I could look at it ?
> 

It's just the trivial extension of the code already in kernel/time.c to
the 64-bit case.

However, it looks like in your case the scaling factor stime/total is
dynamic.  This means that doing scaling by multiplication isn't practical.

I guess I don't understand what function the scaling is supposed to
serve there.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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