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Date:      Thu, 7 Sep 2000 17:48:06 -0700 (PDT)
From:      John Baldwin <jhb@pike.osd.bsdi.com>
To:        Greg Lehey <grog@lemis.com>
Cc:        Steve Ames <steve@virtual-voodoo.com>, freebsd-current@FreeBSD.ORG
Subject:   Re: microuptime() went backwards
Message-ID:  <200009080048.RAA26766@pike.osd.bsdi.com>
In-Reply-To: <20000908101001.G83632@wantadilla.lemis.com> from Greg Lehey at "Sep 8, 2000 10:10:02 am"

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Greg Lehey wrote:
> On Thursday,  7 September 2000 at 17:28:02 -0700, John Baldwin wrote:
> > Steve Ames wrote:
> >> Just upgraded to -CURRENT as of about noon (EST) today. At reboot
> >> I got a lot of these:
> >>
> >> microuptime() went backwards (1.7682417 -> 1.997434)
> >>
> >> I recall reading in -current earlier this week that someone was
> >> looking for victims getting this. What further information can I provide?
> >
> > This is a SMPng issue on UP machines.
> 
> Yes, but it's not the only cause.  We've also seen it on pre-SMPng
> stuff, and Athlons seem to be particularly capable of doing it.  phk
> is looking at it at the moment, and he has an idea what's causing it.
> 
> I'd guess, however, that this *is* the SMPng problem.  It's subtly
> different from other manifestations in that the first time typically
> has 7 digits after the decimal point.

Most definitely an SMPng issue.  If you take a SMP machine and compile a UP
and an SMP kernel on it, the SMP kernel will boot fine, whereas the UP kernel
will generate these warnings.

> Greg
> --
> Finger grog@lemis.com for PGP public key
> See complete headers for address and phone numbers

-- 

John Baldwin <jhb@bsdi.com> -- http://www.FreeBSD.org/~jhb/
PGP Key: http://www.cslab.vt.edu/~jobaldwi/pgpkey.asc
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/


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