Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751856AbWB1AeN (ORCPT ); Mon, 27 Feb 2006 19:34:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751857AbWB1AeN (ORCPT ); Mon, 27 Feb 2006 19:34:13 -0500 Received: from smtp108.mail.mud.yahoo.com ([209.191.85.218]:32430 "HELO smtp108.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S1751856AbWB1AeM (ORCPT ); Mon, 27 Feb 2006 19:34:12 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=JT9CmAAStOYCWj/Apvb8RnOR6AVFRjhud8e6jNgj78dNx3Zv0foeFj8VNNi6x9DWIeydV/HfM9PrbfxyJlXmpaYQ3psc2aiDVgeO1d9acpbGB2y+XhVzj0MLLvkTI8OkgMmPWwAkyM9ZsP0LqsXjILC99kF5HAen8sn8RxA8R70= ; Message-ID: <44039A83.4050604@yahoo.com.au> Date: Tue, 28 Feb 2006 11:34:11 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20050927 Debian/1.7.8-1sarge3 X-Accept-Language: en MIME-Version: 1.0 To: Hans Reiser CC: Ingo Oeser , linux-kernel@vger.kernel.org, Andrew Morton , Marr , reiserfs-dev@namesys.com Subject: Re: Drastic Slowdown of 'fseek()' Calls From 2.4 to 2.6 -- VMM Change? References: <200602241522.48725.marr@flex.com> <20060224211650.569248d0.akpm@osdl.org> <200602261407.33262.ioe-lkml@rameria.de> <4401B233.7050308@yahoo.com.au> <44036670.7060204@namesys.com> In-Reply-To: <44036670.7060204@namesys.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1387 Lines: 43 Hans Reiser wrote: >Sounds like the real problem is that glibc is doing filesystem >optimizations without making them conditional on the filesystem type. > I'm not sure that it should even be conditional on the filesystem type... To me it seems silly to even bother doing it, although I guess there is another level of buffering involved which might mean it makes more sense. >Does anyone know the email address of the glibc guy so we can ask him >not to do that? > > Ulrich Drepper I guess. But don't tell him I sent you ;) >My entry for the ugliest thought of the day: I wonder if the kernel can >test the glibc version and..... > >Hans > >Nick Piggin wrote: > > >>Actually glibc tries to turn this pre-read off if the seek is to a page >>aligned offset, presumably to handle this case. However a big write >>would only have to RMW the first and last partial pages, so pre-reading >>128KB in this case is wrong. >> >>And I would also say a 4K read is wrong as well, because a big read will >>be less efficient due to the extra syscall and small IO. >> >> -- Send instant messages to your online friends http://au.messenger.yahoo.com - 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/