Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 29 Jul 2002 18:32:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 29 Jul 2002 18:32:07 -0400 Received: from dsl-213-023-043-226.arcor-ip.net ([213.23.43.226]:12693 "EHLO starship") by vger.kernel.org with ESMTP id ; Mon, 29 Jul 2002 18:32:06 -0400 Content-Type: text/plain; charset=US-ASCII From: Daniel Phillips To: Rik van Riel , Andrew Morton Subject: Re: [patch 1/13] misc fixes Date: Tue, 30 Jul 2002 00:36:39 +0200 X-Mailer: KMail [version 1.3.2] Cc: lkml References: In-Reply-To: MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Message-Id: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1031 Lines: 25 On Monday 29 July 2002 22:55, Rik van Riel wrote: > On Mon, 29 Jul 2002, Andrew Morton wrote: > > > At some point, when the reverse map is as CPU efficient as we can make > > it, we need to decide whether the remaining cost is worth the benefit. > > I wonder how to do that. > > On a system which isn't swapping, the pte_chain based reverse > maps will never be worth it. However, it seems that well over > 90% of Linux machines have data in swap ... There is also the promise of being able to do active defragmentation, an enabler for large pages, which have been shown to significantly enhance performance due to reduced tlb pressure. So the 'never will be worth it' case is limited to loads that don't create any tlb pressure and don't do any swapping or mmap IO. -- Daniel - 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/