From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 7 May 2002 18:16:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 7 May 2002 18:16:15 -0400 Received: from GS256.SP.CS.CMU.EDU ([128.2.199.27]:55206 "HELO gs256.sp.cs.cmu.edu") by vger.kernel.org with SMTP id ; Tue, 7 May 2002 18:16:13 -0400 Subject: Re: Memory Barrier Definitions From: justincarlson@cmu.edu To: Alan Cox Cc: Dave Engebretsen , linux-kernel@vger.kernel.org In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-DVwoIHhZOh96fRnw5VE2" X-Mailer: Ximian Evolution 1.0.4.99 Date: 07 May 2002 18:15:50 -0400 Message-Id: <1020809750.13627.24.camel@gs256.sp.cs.cmu.edu> Mime-Version: 1.0 Source-Info: Sender is really justinca+@gs256.sp.cs.cmu.edu Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --=-DVwoIHhZOh96fRnw5VE2 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Tue, 2002-05-07 at 16:27, Alan Cox wrote: > and our current heirarchy is a little bit more squashed than that. I'd=20 > agree. We actually hit a corner case of this on the IDT winchip x86 where > we run relaxed store ordering and have to define wmb() as a locked add of > zero to the top of stack - which does have a penalty that isnt needed > for CPU ordering. >=20 > How much of this impacts Mips64 ? In terms of the MIPS{32|64} ISA, the current primitives seem fine; there's only 1 option defined in the ISA: 'sync'. Order for all off-cache accesses is guaranteed around a sync. It gets a bit more complicated when you talk about what particular implementations do, and ordering rules for uncached vs cached accesses, but to the best of my knowledge there aren't any fundamental problems as described for the PPC. -Justin --=-DVwoIHhZOh96fRnw5VE2 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQA82FIV47Lg4cGgb74RAnDlAKDHoFrOfxYmSy+knzQjz8zz31JecwCggr6Q YferDGlpy6aHA6IvI4DrD4w= =jLhA -----END PGP SIGNATURE----- --=-DVwoIHhZOh96fRnw5VE2--