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, 24 May 2002 05:00:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 24 May 2002 05:00:34 -0400 Received: from denise.shiny.it ([194.20.232.1]:26019 "EHLO denise.shiny.it") by vger.kernel.org with ESMTP id ; Fri, 24 May 2002 05:00:33 -0400 Message-ID: X-Mailer: XFMail 1.4.7 on Linux X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <3CED4843.2783B568@zip.com.au> Date: Fri, 24 May 2002 10:59:42 +0200 (CEST) From: Giuliano Pochini To: linux-kernel@vger.kernel.org Subject: Re: Poor read performance when sequential write presents Cc: "chen, xiangping" , Andrew Morton Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >> I did a IO test with one sequential read and one sequential write >> to different files. I expected somewhat similar throughput on read >> and write. But it seemed that the read is blocked until the write >> finishes. After the write process finished, the read process slowly >> picks up the speed. Is Linux buffer cache in favor of write? How >> to tune it? > [...] > 2: Apply http://www.zip.com.au/~akpm/linux/patches/2.4/2.4.19-pre5/read-latency2.patch Hmmm, someone wrote a patch to fix another related problem: the fact that multiple readers read at a very different speed. It's not unusual that one reader gets stuck until all other have finished. I don't remember who wrote that patch, sorry. Bye.