From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964983AbWD0IsZ (ORCPT ); Thu, 27 Apr 2006 04:48:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964988AbWD0IsZ (ORCPT ); Thu, 27 Apr 2006 04:48:25 -0400 Received: from smtp107.mail.mud.yahoo.com ([209.191.85.217]:8017 "HELO smtp107.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S964983AbWD0IsX (ORCPT ); Thu, 27 Apr 2006 04:48:23 -0400 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=H3sELoR5pBYz0Fqv+ut9z1RKfs3Orj9QgOvuOfUiOTk/PGzNwvsT7rRKXG+jL0wCkfXd/H86Vlc3SRr2emhpM35DMof5JMOh5P2eyKS32HGoHhSwNiZYIbIjsQclF7GiR7MaGAGfnvw2sv5x1N85vyC24AynZgOy0RBLMd8Gf7A= ; Message-ID: <44507AA9.2010005@yahoo.com.au> Date: Thu, 27 Apr 2006 18:02:49 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Jens Axboe CC: Andrew Morton , torvalds@osdl.org, linux-kernel@vger.kernel.org, npiggin@suse.de, linux-mm@kvack.org Subject: Re: Lockless page cache test results References: <20060426135310.GB5083@suse.de> <20060426095511.0cc7a3f9.akpm@osdl.org> <20060426174235.GC5002@suse.de> <20060426111054.2b4f1736.akpm@osdl.org> <20060426191557.GA9211@suse.de> <20060426131200.516cbabc.akpm@osdl.org> <20060427074533.GJ9211@suse.de> <4450796A.2030908@yahoo.com.au> In-Reply-To: <4450796A.2030908@yahoo.com.au> 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 Nick Piggin wrote: > Jens Axboe wrote: > >> Things look pretty bad for the lockless kernel though, Nick any idea >> what is going on there? The splice change is pretty simple, see the top >> three patches here: > > > Could just be the use of spin lock instead of read lock. > > I don't think it would be hard to convert find_get_pages_contig > to be lockless. > > Patched vanilla numbers look nicer, but I'm curious as to why > __do_page_cache was so bad before, if the file was in cache. > Presumably it should not more than double tree_lock acquisition... > it isn't getting called multiple times for each page, is it? Hmm, what's more, find_get_pages_contig shouldn't result in any fewer tree_lock acquires than the open coded thing there now (for the densely populated pagecache case). -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com