Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262065AbUKJXX3 (ORCPT ); Wed, 10 Nov 2004 18:23:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262120AbUKJXX3 (ORCPT ); Wed, 10 Nov 2004 18:23:29 -0500 Received: from clock-tower.bc.nu ([81.2.110.250]:26322 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id S262065AbUKJXXX (ORCPT ); Wed, 10 Nov 2004 18:23:23 -0500 Subject: Re: mmap vs. O_DIRECT From: Alan Cox To: Bill Davidsen Cc: Linux Kernel Mailing List In-Reply-To: References: Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1100125196.20792.15.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Wed, 10 Nov 2004 22:19:58 +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 604 Lines: 13 On Mer, 2004-11-10 at 00:05, Bill Davidsen wrote: > I have an application which does a lot of mmap to process its data. The > huge waitio time makes me think that mmap isn't doing direct i/o even > when things are alligned. Make sure you are using MAP_SHARED in such cases so that the object you have is the page cache object, also remember to use madvise - 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/