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Date: Tue, 15 Nov 2005 04:49:54 -0200
From: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Shailabh Nagar <nagar@watson.ibm.com>, linux-kernel@vger.kernel.org,
       Ingo Molnar <mingo@elte.hu>
Subject: Re: [Patch 1/4] Delay accounting: Initialization
Message-ID: <20051115064954.GB31904@logos.cnet>
References: <43796596.2010908@watson.ibm.com> <20051114202017.6f8c0327.akpm@osdl.org>
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On Mon, Nov 14, 2005 at 08:20:17PM -0800, Andrew Morton wrote:
> Shailabh Nagar <nagar@watson.ibm.com> wrote:
> >
> > +	*ts = sched_clock();
> 
> I'm not sure that it's kosher to use sched_clock() for fine-grained
> timestamping like this.  Ingo had issues with it last time this happened?  

If the system boots with use_rtc == 0 you're going to get jiffies based
resolution from sched_clock(). I have a 1GHz Pentium 3 around here which
does that.

Maybe use do_gettimeofday() for such systems?

Would be nice to have a sort of per-arch overridable "gettime()" function?

> <too lazy to read all the code> Do you normalise these numbers in some
> manner before presenting them to userspace?  If so, by what means?
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