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
Date: Tue, 15 Nov 2005 04:49:54 -0200 [thread overview]
Message-ID: <20051115064954.GB31904@logos.cnet> (raw)
In-Reply-To: <20051114202017.6f8c0327.akpm@osdl.org>
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?
next prev parent reply other threads:[~2005-11-15 12:01 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-15 4:35 [Patch 1/4] Delay accounting: Initialization Shailabh Nagar
2005-11-15 4:20 ` Andrew Morton
2005-11-15 6:49 ` Marcelo Tosatti [this message]
2005-11-15 15:19 ` Shailabh Nagar
2005-11-15 12:20 ` Marcelo Tosatti
2005-11-15 12:34 ` Marcelo Tosatti
2005-11-15 15:08 ` Shailabh Nagar
2005-11-16 1:06 ` Peter Chubb
2005-11-16 1:48 ` Shailabh Nagar
2005-11-16 1:50 ` Andi Kleen
2005-11-16 1:52 ` Peter Chubb
2005-11-15 4:25 ` Parag Warudkar
2005-11-15 22:29 ` Shailabh Nagar
2005-11-15 22:53 ` Parag Warudkar
2005-11-16 0:45 ` Shailabh Nagar
2005-11-16 2:41 ` Parag Warudkar
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