From owner-freebsd-current Thu Sep 7 17:51:22 2000 Delivered-To: freebsd-current@freebsd.org Received: from wantadilla.lemis.com (wantadilla.lemis.com [192.109.197.80]) by hub.freebsd.org (Postfix) with ESMTP id A9BDE37B424 for ; Thu, 7 Sep 2000 17:51:18 -0700 (PDT) Received: (from grog@localhost) by wantadilla.lemis.com (8.11.0/8.9.3) id e880p4v10499; Fri, 8 Sep 2000 10:21:04 +0930 (CST) (envelope-from grog) Date: Fri, 8 Sep 2000 10:21:04 +0930 From: Greg Lehey To: John Baldwin Cc: Steve Ames , freebsd-current@FreeBSD.ORG Subject: Re: microuptime() went backwards Message-ID: <20000908102104.H83632@wantadilla.lemis.com> References: <20000908101001.G83632@wantadilla.lemis.com> <200009080048.RAA26766@pike.osd.bsdi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <200009080048.RAA26766@pike.osd.bsdi.com>; from jhb@pike.osd.bsdi.com on Thu, Sep 07, 2000 at 05:48:06PM -0700 Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-418-838-708 WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Thursday, 7 September 2000 at 17:48:06 -0700, John Baldwin wrote: > 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. The point I'm making is that we've had these problems before SMPng, and that you can't automatically assume that it's SMPng just because you get the messages. On the other hand, the 7 digits seem to be a pretty reliable signature. Greg -- Finger grog@lemis.com for PGP public key See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message