From owner-freebsd-smp Mon Dec 23 22:06:44 1996 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.4/8.8.4) id WAA10662 for smp-outgoing; Mon, 23 Dec 1996 22:06:44 -0800 (PST) Received: from root.com (implode.root.com [198.145.90.17]) by freefall.freebsd.org (8.8.4/8.8.4) with ESMTP id WAA10657 for ; Mon, 23 Dec 1996 22:06:42 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by root.com (8.7.6/8.6.5) with SMTP id WAA27540; Mon, 23 Dec 1996 22:05:33 -0800 (PST) Message-Id: <199612240605.WAA27540@root.com> X-Authentication-Warning: implode.root.com: Host localhost [127.0.0.1] didn't use HELO protocol To: Erich Boleyn cc: smp@freebsd.org, haertel@ichips.intel.com, wscott@ichips.intel.com Subject: Re: I think we have the culprit!! (was -> Re: Eureka (maybe...) (was -> Re: P6 problem idea ) ) In-reply-to: Your message of "Mon, 23 Dec 1996 22:21:49 PST." From: David Greenman Reply-To: dg@root.com Date: Mon, 23 Dec 1996 22:05:33 -0800 Sender: owner-smp@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > >Erich Boleyn writes: > >> I tried shutting off the page global stuff, and while I don't have >> a difinitively long run yet, it has run through 3 full kernel compiles >> with no crash yet. I'll run it for the next 1 1/2 hours and see if >> it lives through that. If so, I think we have our main culprit (I'll >> also post the (small) code change which synchronizes the CPUs on TLB >> shootdown before letting the sender continue). > >Well, after 2 hours of kernel builds, and now a few sets of 4 parallel >kernel builds later, the system is still running great. > >I think we have our culprit... the Page Global stuff (plus adding the >TLB shootdown synchronization may be helping a little with stability, but >it's absence doesn't appear to be the major cause). > >> All that said, I'm very surprised that this *isn't* also a serious >> problem on the Pentium (the Pentium has the Page Global stuff as >> well... I didn't look to see if it is used for the Pentium as well >> as the Pentium Pro). > >I might be confused here, but as mentioned in the above comment, I >thought this was implemented in the Pentium as well. Can someone >who remembers better (or has the "Appendix H" equivalent released >documentation) comment? Tge "PGE" feature doesn't appear to be present in the stepping 4 or stepping 12 chips that I have here...so if the Pentium has the feature, it must have been added only very recently. -DG David Greenman Core-team/Principal Architect, The FreeBSD Project