From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759248AbYHTPEW (ORCPT ); Wed, 20 Aug 2008 11:04:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758046AbYHTPEL (ORCPT ); Wed, 20 Aug 2008 11:04:11 -0400 Received: from bohort.kerlabs.com ([62.160.40.57]:54241 "EHLO bohort.kerlabs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758042AbYHTPEK (ORCPT ); Wed, 20 Aug 2008 11:04:10 -0400 Date: Wed, 20 Aug 2008 17:04:08 +0200 From: Louis Rilling To: Martin Uecker Cc: Steven Whitehouse , linux-kernel@vger.kernel.org Subject: Re: distributed shared memory / mmap Message-ID: <20080820150408.GE581@hawkmoon.kerlabs.com> Reply-To: Louis.Rilling@kerlabs.com References: <1219238336.8097.29.camel@localhost> <1219243404.20622.156.camel@quoit> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=_bohort-26697-1219244518-0001-2" Content-Disposition: inline In-Reply-To: <1219243404.20622.156.camel@quoit> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a MIME-formatted message. If you see this text it means that your E-mail software does not support MIME-formatted messages. --=_bohort-26697-1219244518-0001-2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Aug 20, 2008 at 03:43:24PM +0100, Steven Whitehouse wrote: > Hi, >=20 > On Wed, 2008-08-20 at 15:18 +0200, Martin Uecker wrote: > >=20 > > Hi! > >=20 > > Is there any easy way to get shared memory between to > > processes on different machines? It seems possible using mmap > > on a file system like GFS on top of a distributed block device. > >=20 > >=20 > > Sincerly, > > Martin Uecker > >=20 > Yes, you can do it using GFS/GFS2 and it should work. On the other hand, > don't do it. Its probably not what you want and unlikely to give you > good performance since the locking is "per inode" and thus you'll > generate a lot of cache flushing if there is any appreciable amount of > writing to the shared region. If you have a read mostly (or only) > workload, then it will work much better. Alternatively, you can use kernel-level DSM like provided by Kerrighed. Kerrighed provides cluster-wide SYSV shm segments, which sharing is handled at the page level -> far better than the inode level. You may find this solution not-so-easy though... Regards, Louis --=20 Dr Louis Rilling Kerlabs Skype: louis.rilling Batiment Germanium Phone: (+33|0) 6 80 89 08 23 80 avenue des Buttes de Coesmes http://www.kerlabs.com/ 35700 Rennes --=_bohort-26697-1219244518-0001-2 Content-Type: application/pgp-signature; name="signature.asc" Content-Transfer-Encoding: 7bit Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFIrDJoVKcRuvQ9Q1QRAqeAAKCRDWCef83Th7CpZfJRUVppim5DmACdFmzQ uKnjG3f5K/er1tqJSSJCdMo= =Z4/3 -----END PGP SIGNATURE----- --=_bohort-26697-1219244518-0001-2--