From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 25 May 2001 04:25:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 25 May 2001 04:24:40 -0400 Received: from cisco7500-mainGW.gts.cz ([194.213.32.131]:7172 "EHLO bug.ucw.cz") by vger.kernel.org with ESMTP id ; Fri, 25 May 2001 04:24:27 -0400 Date: Wed, 23 May 2001 16:22:28 +0000 From: Pavel Machek To: Bharath Madhavan Cc: linux-kernel@vger.kernel.org Subject: Re: Speeding up VFS using HW assist Message-ID: <20010523162227.A33@toy.ucw.cz> In-Reply-To: <25369470B6F0D41194820002B328BDD2071790@ATLOPS> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0.1i In-Reply-To: <25369470B6F0D41194820002B328BDD2071790@ATLOPS>; from bharath_madhavan@ivivity.com on Tue, May 22, 2001 at 05:11:37PM -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > I will be using Linux as the OS for an embedded system. > I was looking into 2.4.4 kernel code and saw the dcache implementation > in VFS which is pretty neat and fast by itself. > > My question is, will I gain any considerable efficiency in file system > access > if I can move this "pathname -> inode" lookup into some proprietery > HW assist mechanism and take out the dcache hashing and "cached_lookup" > function. I doubt it will do much difference. How much time is spent in kernel in your workload? What kind of embedded system is that? > How good(bad) was it before the dcache implementation and in which release > was dcache feature added (was it only after 2.2.x release). > Did we get 2-3 times better performance with dcache? (if not, how much?) I'd be surprised if dcache made more than 20% speedup. > Can anyone suggest any other place in the file system (VFS and EXT2) where > we > can use any HW assist (let us say FPGA implementing search, lookup, etc.) > to speed up file-system access (both for opening and read/write) Dumping ext2 for reiserfs? ;-) -- Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt, details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.