From owner-freebsd-smp Sun Mar 31 9:52:51 2002 Delivered-To: freebsd-smp@freebsd.org Received: from wall.polstra.com (wall-gw.polstra.com [206.213.73.130]) by hub.freebsd.org (Postfix) with ESMTP id D5AE137B405 for ; Sun, 31 Mar 2002 09:52:37 -0800 (PST) Received: from vashon.polstra.com (vashon.polstra.com [206.213.73.13]) by wall.polstra.com (8.11.3/8.11.3) with ESMTP id g2VHqao96095; Sun, 31 Mar 2002 09:52:36 -0800 (PST) (envelope-from jdp@wall.polstra.com) Received: (from jdp@localhost) by vashon.polstra.com (8.11.6/8.11.0) id g2VHqab18408; Sun, 31 Mar 2002 09:52:36 -0800 (PST) (envelope-from jdp) Date: Sun, 31 Mar 2002 09:52:36 -0800 (PST) Message-Id: <200203311752.g2VHqab18408@vashon.polstra.com> To: smp@freebsd.org From: John Polstra Cc: dillon@apollo.backplane.com Subject: Re: RE: Syscall contention tests return, userret() bugs/issues. In-Reply-To: <200203311747.g2VHlII89488@apollo.backplane.com> References: <200203292207.g2TM7Fi67491@apollo.backplane.com> <200203311729.g2VHT5h18352@vashon.polstra.com> <200203311747.g2VHlII89488@apollo.backplane.com> Organization: Polstra & Co., Seattle, WA Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org In article <200203311747.g2VHlII89488@apollo.backplane.com>, Matthew Dillon wrote: > > :> the cache, on IA32, it's write-through to main-memory which > :> invalidates all other cpu's caches for that cache line. > : > :No, it's not nearly that bad. See section 9.2 of the IA-32 Intel > :Architecture Software Developer's Manual, Volume 3 (24547203.pdf from > :developer.intel.com). It describes what happens in a couple of > :different scenarios, for example: > > This is not a case that typically occurs. Because intel caches are > write-through the processor that does the write will flush the dirty > cache line to main memory in fairly short order. Why do you keep saying the Intel caches are write-through? They've been write-back since the Pentium. See table 9-2 in the same document I cited before. John -- John Polstra John D. Polstra & Co., Inc. Seattle, Washington USA "Disappointment is a good sign of basic intelligence." -- Chögyam Trungpa To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message