From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: Re: NFSv4/pNFS possible POSIX I/O API standards Date: Tue, 5 Dec 2006 10:01:09 -0700 Message-ID: <20061205170109.GP3013@parisc-linux.org> References: <6.2.3.4.2.20061127213243.04f786c0@cic-mail.lanl.gov> <20061128055428.GA29891@infradead.org> <20061129090450.GA16296@infradead.org> <20061129122313.GG14315@parisc-linux.org> <20061129123913.GA15994@infradead.org> <4570ACD1.7060800@mcs.anl.gov> <4574BF52.6090600@mcs.anl.gov> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Rob Ross , Christoph Hellwig , Gary Grider , linux-fsdevel@vger.kernel.org Return-path: Received: from palinux.external.hp.com ([192.25.206.14]:41924 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S968455AbWLERBK (ORCPT ); Tue, 5 Dec 2006 12:01:10 -0500 To: Latchesar Ionkov Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Tue, Dec 05, 2006 at 05:47:16PM +0100, Latchesar Ionkov wrote: > I think that the main problem is that all these file systems resove a > path name, one directory at a time bringing the server to its knees by > the huge amount of requests. I would like to see what the performance > is if you a) cache the last few hundred lookups on the server side, > and b) modify VFS and the file systems to support multi-name lookups. > Just assume for a moment that there is no any way to get these new > operations in (which is probaly going to be true anyway :). What other > solutions can you think of? :) How exactly would you want a multi-name lookup to work? Are you saying that open("/usr/share/misc/pci.ids") should ask the server "Find usr, if you find it, find share, if you find it, find misc, if you find it, find pci.ids"? That would be potentially very wasteful; consider mount points, symlinks and other such effects on the namespace. You could ask the server to do a lot of work which you then discard ... and that's not efficient.