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Date: Fri, 8 Mar 2002 12:30:26 -0800 (PST)
From: Davide Libenzi <davidel@xmailserver.org>
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To: Jamie Lokier <lk@tantalophile.demon.co.uk>
cc: "H. Peter Anvin" <hpa@zytor.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Alan Cox <alan@lxorguk.ukuu.org.uk>,
        Terje Eggestad <terje.eggestad@scali.com>,
        Ben Greear <greearb@candelatech.com>,
        george anzinger <george@mvista.com>
Subject: Re: gettimeofday() system call timing curiosity
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On Fri, 8 Mar 2002, Jamie Lokier wrote:

> It's the _median_ that varies from 453 to 470, not the _mean_, so the
> accumulation to 17000 cycles doesn't apply.

I was doing something similar and i got huge numbers out of a small mean.
It was the recalc loop that hit inside the scheduler or in this case it
could be a schedule() entry due a need_resched set by the timer. From the
number of cycles it seems possible.



- Davide


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