From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 9D5416B0078 for ; Wed, 24 Feb 2010 00:24:16 -0500 (EST) Date: Wed, 24 Feb 2010 16:24:09 +1100 From: Dave Chinner Subject: Re: [RFC] nfs: use 2*rsize readahead size Message-ID: <20100224052409.GI16175@discord.disaster> References: <20100224024100.GA17048@localhost> <20100224032934.GF16175@discord.disaster> <20100224042414.GG16175@discord.disaster> <20100224044356.GA2007@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100224044356.GA2007@localhost> Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: Trond Myklebust , "linux-nfs@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , Linux Memory Management List , LKML List-ID: On Wed, Feb 24, 2010 at 12:43:56PM +0800, Wu Fengguang wrote: > On Wed, Feb 24, 2010 at 12:24:14PM +0800, Dave Chinner wrote: > > On Wed, Feb 24, 2010 at 02:29:34PM +1100, Dave Chinner wrote: > > > That's doing a cached read out of the server cache, right? You > > > might find the results are different if the server has to read the > > > file from disk. I would expect reads from the server cache not > > > to require much readahead as there is no IO latency on the server > > > side for the readahead to hide.... > > > > FWIW, if you mount the client with "-o rsize=32k" or the server only > > supports rsize <= 32k then this will probably hurt throughput a lot > > because then readahead will be capped at 64k instead of 480k.... > > I should have mentioned that in changelog.. Hope the updated one > helps. Sorry, my fault for not reading the code correctly. Cheers, Dave. -- Dave Chinner david@fromorbit.com -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org