Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261513AbVBHLhL (ORCPT ); Tue, 8 Feb 2005 06:37:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261517AbVBHLhK (ORCPT ); Tue, 8 Feb 2005 06:37:10 -0500 Received: from alg138.algor.co.uk ([62.254.210.138]:15330 "EHLO mail.linux-mips.net") by vger.kernel.org with ESMTP id S261513AbVBHLhH (ORCPT ); Tue, 8 Feb 2005 06:37:07 -0500 Date: Tue, 8 Feb 2005 11:31:32 +0000 From: Ralf Baechle To: Robin Holt Cc: David Woodhouse , Christoph Lameter , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: A scrub daemon (prezeroing) Message-ID: <20050208113131.GA5143@linux-mips.org> References: <1106828124.19262.45.camel@hades.cambridge.redhat.com> <20050127131228.GB31288@lnx-holt.americas.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050127131228.GB31288@lnx-holt.americas.sgi.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 870 Lines: 20 On Thu, Jan 27, 2005 at 07:12:29AM -0600, Robin Holt wrote: > > Some architectures tend to have spare DMA engines lying around. There's > > no need to use the CPU for zeroing pages. How feasible would it be for > > scrubd to use these? > > An earlier proposal that Christoph pushed would have used the BTE on > sn2 for this. Are you thinking of using the BTE on sn0/sn1 mips? On BCM1250 SOCs we've gone a step beyond that and use the Data Mover to clear_page(), see arch/mips/mm/pg-sb1.c. It's roughly comparable to the SN0 BTE. Broadcom has meassured a quite large performance win for such a small code change. Ralf - 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/