Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264644AbTIDEKX (ORCPT ); Thu, 4 Sep 2003 00:10:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264658AbTIDEKX (ORCPT ); Thu, 4 Sep 2003 00:10:23 -0400 Received: from magic-mail.adaptec.com ([216.52.22.10]:13187 "EHLO magic.adaptec.com") by vger.kernel.org with ESMTP id S264644AbTIDEKR (ORCPT ); Thu, 4 Sep 2003 00:10:17 -0400 Date: Wed, 3 Sep 2003 21:37:55 +0530 (IST) From: Nagendra Singh Tomar X-X-Sender: tomar@localhost.localdomain Reply-To: nagendra_tomar@adaptec.com To: Jamie Lokier cc: Geert Uytterhoeven , Roman Zippel , Kars de Jong , Linux/m68k kernel mailing list , Linux Kernel Development Subject: Re: x86, ARM, PARISC, PPC, MIPS and Sparc folks please run this In-Reply-To: <20030903132932.GA21530@mail.jlokier.co.uk> Message-ID: Organization: Adaptec MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1450 Lines: 43 Jamie, Just wondered if the store buffer is snooped in some architectures. In that case I believe the OS need not do anything for serialization (except for aliases, if they do not hit the same cache line). In x86 store buffer is not snooped which leads to all these serialization issues (other CPUs looking at stale value of data which is in the store buffer of some other CPU). Pl correct me if I have got anything wrong/ Thanx, tomar On Wed, 3 Sep 2003, Jamie Lokier wrote: > Geert Uytterhoeven wrote: > > > BTW the 020/030 caches are VIVT (and also only writethrough), the > 040/060 > > > caches are PIPT. > > > > That explains a bit. But the '060 stores are coherent, while the '040 > stores > > aren't. > > The L1 cache is coherent on the '040 according to the results. It's > the store buffer snooping which fails. Presumably the CPU core is > looking ahead at recent writes comparing just virtual addresses. > > -- Jamie > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" > in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/