Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750760AbWEZOAW (ORCPT ); Fri, 26 May 2006 10:00:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750761AbWEZOAW (ORCPT ); Fri, 26 May 2006 10:00:22 -0400 Received: from cantor.suse.de ([195.135.220.2]:60308 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S1750760AbWEZOAV (ORCPT ); Fri, 26 May 2006 10:00:21 -0400 To: Andrew Morton Cc: linux-kernel@vger.kernel.org, wfg@mail.ustc.edu.cn, mstone@mathom.us Subject: Re: [PATCH 00/33] Adaptive read-ahead V12 References: <348469535.17438@ustc.edu.cn> <20060525084415.3a23e466.akpm@osdl.org> From: Andi Kleen Date: 26 May 2006 16:00:14 +0200 In-Reply-To: <20060525084415.3a23e466.akpm@osdl.org> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 895 Lines: 15 Andrew Morton writes: > > These are nice-looking numbers, but one wonders. If optimising readahead > makes this much difference to postgresql performance then postgresql should > be doing the readahead itself, rather than relying upon the kernel's > ability to guess what the application will be doing in the future. Because > surely the database can do a better job of that than the kernel. With that argument we should remove all readahead from the kernel? Because it's already trying to guess what the application will do. I suspect it's better to have good readahead code in the kernel than in a zillion application. -Andi - 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/