From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752161Ab1AIABQ (ORCPT ); Sat, 8 Jan 2011 19:01:16 -0500 Received: from cantor2.suse.de ([195.135.220.15]:60916 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751737Ab1AIABP (ORCPT ); Sat, 8 Jan 2011 19:01:15 -0500 Date: Sat, 8 Jan 2011 15:56:08 -0800 From: Greg KH To: Linus Torvalds Cc: Linux Kernel Mailing List , Nick Piggin , Al Viro , Andrew Morton , David Miller Subject: Re: Quick merge window note.. Message-ID: <20110108235608.GA4470@suse.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 07, 2011 at 05:32:46PM -0800, Linus Torvalds wrote: > But it's rather impressive and I really wanted to merge it, because > some of the performance numbers are pretty stunning. For example, a > hot-cache "find . -size" on my home directory (which basically just > does name lookups to get the stat information for every file > recursively) became 35% faster. And that's the _unthreaded_ case. Not > some odd high-end scalability thing, and not some recompiled binary > taking advantage of new facilities. Pathname lookup is just simply > faster. > > On the scary side, it's worth noticing that if you see any problems, > and you think it might be due to the new rcu lookup, rather than > bisect _everything_ (the merge window has already brought in 3700+ > commits), it may be worth just checking the VFS scale tip itself. > That's fairly easy, because it's based on plain 2.6.37 (which if it > isn't stable for you, we have bigger problems than the RCU lookup), > and is just 57 commits up until commit b3e19d924b6e ("fs: scale > mntget/mntput"). Thanks for the heads up. In some initial testing here, it all looks good to me. greg k-h