From owner-p4-projects@FreeBSD.ORG Mon Apr 21 13:42:24 2003 Return-Path: Delivered-To: p4-projects@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 32767) id B06CB37B404; Mon, 21 Apr 2003 13:42:23 -0700 (PDT) Delivered-To: perforce@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6664337B401 for ; Mon, 21 Apr 2003 13:42:23 -0700 (PDT) Received: from ns1.xcllnt.net (209-128-86-226.BAYAREA.NET [209.128.86.226]) by mx1.FreeBSD.org (Postfix) with ESMTP id 51A1943FF9 for ; Mon, 21 Apr 2003 13:42:22 -0700 (PDT) (envelope-from marcel@xcllnt.net) Received: from athlon.pn.xcllnt.net (athlon.pn.xcllnt.net [192.168.4.3]) by ns1.xcllnt.net (8.12.9/8.12.9) with ESMTP id h3LKgMwk093375 for ; Mon, 21 Apr 2003 13:42:22 -0700 (PDT) (envelope-from marcel@piii.pn.xcllnt.net) Received: from athlon.pn.xcllnt.net (localhost [127.0.0.1]) by athlon.pn.xcllnt.net (8.12.9/8.12.9) with ESMTP id h3LKgMtc000870 for ; Mon, 21 Apr 2003 13:42:22 -0700 (PDT) (envelope-from marcel@athlon.pn.xcllnt.net) Received: (from marcel@localhost) by athlon.pn.xcllnt.net (8.12.9/8.12.9/Submit) id h3LKgL0M000869 for perforce@freebsd.org; Mon, 21 Apr 2003 13:42:21 -0700 (PDT) Date: Mon, 21 Apr 2003 13:42:21 -0700 From: Marcel Moolenaar To: Perforce Change Reviews Message-ID: <20030421204221.GA830@athlon.pn.xcllnt.net> References: <200304212028.h3LKSg2v082838@repoman.freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200304212028.h3LKSg2v082838@repoman.freebsd.org> User-Agent: Mutt/1.5.3i Subject: Re: PERFORCE change 29365 for review X-BeenThere: p4-projects@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: p4 projects tree changes List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Apr 2003 20:42:24 -0000 On Mon, Apr 21, 2003 at 01:28:42PM -0700, Marcel Moolenaar wrote: > http://perforce.freebsd.org/chv.cgi?CH=29365 > > Change 29365 by marcel@marcel_nfs on 2003/04/21 13:27:48 > > Use a non-trapping implementation for pmap_kextract. > This has been deliberately made non-inlined for now > to help profiling, debugging and whatsnot. Be extra > careful (probably over-correctingly so :-) with the > address passed to us, because it may be an address > given to use from user space. > > Note that an inlined or partially inlined version > should be used eventually. It appears that UMA is > a regular user of pmap_kextract and rudimentary > testing showed that it's mostly for direct mapped > KVAs. Doing the test for direct mapped KVAs inlined > will probably be worth it. > > Valuable insights by: jake JFYI: I noticed a reduction in the number of Nested TLB faults, so it appears that not depending on the cpu's TLB for pmap_kextract has a side-effect of not polluting the translation cache. I also have a nagging suspicion that it may have been the cause of not being able to run a MP kernel on the HP boxes in the FreeBSD cluster, even though SMP works (roughly) on the BigSur. On the HP boxes the BSP and AP get entangled in a life-lock where the AP holds sched_lock, while waiting for Giant that the BSP holds. The BSP is likely in hardclock and the AP is typically in UMA (I may have got the details slightly wrong). Since the AP has mostly a clean translation cache it's probably faulting a lot and may possibly end up in vm_fault. Again, this is just a nagging suspicion... -- Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net