Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261270AbVCQX71 (ORCPT ); Thu, 17 Mar 2005 18:59:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261303AbVCQX71 (ORCPT ); Thu, 17 Mar 2005 18:59:27 -0500 Received: from fire.osdl.org ([65.172.181.4]:40656 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S261270AbVCQX7X (ORCPT ); Thu, 17 Mar 2005 18:59:23 -0500 Date: Thu, 17 Mar 2005 15:59:08 -0800 From: Andrew Morton To: Christoph Lameter Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] Prezeroing V8 Message-Id: <20050317155908.56e77b8e.akpm@osdl.org> In-Reply-To: References: <20050317140831.414b73bb.akpm@osdl.org> <20050317151151.47fd6e5f.akpm@osdl.org> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1022 Lines: 27 Christoph Lameter wrote: > > On Thu, 17 Mar 2005, Andrew Morton wrote: > > > > > It's hard to know what to think about this without benchmarking numbers. > > http://oss.sgi.com/projects/page_fault_performance/ Oh no, not that page again ;) Seems to say that prezeroing makes negligible difference to kernel builds, but speeds up a big malloc+memset by 3x to 4x, yes? Are there any real-worldish workloads which show an appreciable benefit? The large speedup for a big memset seems odd - I assume it's simply transferring CPU load from the user's process over to kscrubd. Or is it the fancy page-zeroing hardware? How do we differentiate the two? Are there any workloads which are seeing a benefit on a CPU which doesn't have the zeroing hardware? - 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/