From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750880AbVLOSf1 (ORCPT ); Thu, 15 Dec 2005 13:35:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750897AbVLOSf1 (ORCPT ); Thu, 15 Dec 2005 13:35:27 -0500 Received: from mail.kroah.org ([69.55.234.183]:1453 "EHLO perch.kroah.org") by vger.kernel.org with ESMTP id S1750880AbVLOSf0 (ORCPT ); Thu, 15 Dec 2005 13:35:26 -0500 Date: Thu, 15 Dec 2005 10:35:07 -0800 From: Greg KH To: Patrick Fritzsch Cc: linux-kernel@vger.kernel.org Subject: Re: slow sync of fat 32 hotplugged devices Message-ID: <20051215183506.GA16574@kroah.com> References: <43A1B5B9.2040307@cip.physik.uni-muenchen.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43A1B5B9.2040307@cip.physik.uni-muenchen.de> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 15, 2005 at 07:28:09PM +0100, Patrick Fritzsch wrote: > Hallo, > I checked out suse10 lately and discovered some annoying behaviour in > hotplugging an USB Stick. > > It seems that the hal daemon mounts a usbstick in fat32 mode, where > default the sync option ist on. Actually this is a nice behaviour, > because a cp to the stick should last so long until the file was > completly written. This is a HAL issue, just have it mount without sync enabled and your speed will return. > Actually the performance is very bad. A 200 MB file needs around 10 > Minutes in sync mode, while it needs around 1 Minute in not synchronous > mode + executing a sync command later. > > I guess that the kernel checks after every block of the file, which is > written, if the stick has really written it, which leads to such a big > slowdown. There are already lots of comments of this in the web, where > the solution is always to disable the sync mode in the hal daemon device > files. > > Wouldnt it be a nice behaviour, if you could mount a file in a new sync > mode, where it isnt synchronized during writing a file, only when a > close ioctl command was executed on a filehandle? > sync writing to hotplugged devices would be a lot faster then. Yes it would, and I'm pretty sure people are already working on this :) But if you have some patches that enable this functionality already, please post them. thanks, greg k-h