From: Dave Chinner Subject: Re: [GIT PULL] ext4 updates for 3.9 Date: Fri, 1 Mar 2013 00:18:13 +1100 Message-ID: <20130228131813.GO5551@dastard> References: <20130227170157.GA222@x4> <98C6DE45-F050-4AAD-82E2-7352F5BB0A5D@gmail.com> <20130227172256.GA236@x4> <7BFB2135-A1F0-4B6D-9962-16E75E5560F8@gmail.com> <20130227174553.GA224@x4> <20130227184912.GA19624@thunk.org> <20130227185625.GA224@x4> <20130227191923.GA1121@redhat.com> <20130227192907.GB14253@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Theodore Ts'o , Dave Jones , Markus Trippelsdorf , Linus Torvalds , "gnehzuil.liu" , Zheng Liu , Borislav Petkov , "linux-ext4@vger.kernel.org" , "linux-kernel@vger.kernel.org" Return-path: Content-Disposition: inline In-Reply-To: <20130227192907.GB14253@thunk.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Wed, Feb 27, 2013 at 02:29:07PM -0500, Theodore Ts'o wrote: > On Wed, Feb 27, 2013 at 02:19:23PM -0500, Dave Jones wrote: > > > > Looks like it's fixed here too. > > > > How did this make it through -next without anyone hitting it ? > > > Is anyone running xfstests or similar on linux-next regularly ? > > I run xfstests on the ext4 tree, and I ran it on ext4 plus Linus's tip > before I submitted a pull request. The problem is that XFSTESTS is > S-L-O-W if you use large partitions, so typically I use a 5GB > partition sizes for my test runs. This isn't the case for XFS. I typically see 1TB scratch devices only being ~10-20% slower than 10GB scratch devices, and 10TB only being a little slower than 1TB scratch devices. I have to use sparse devices and --large-fs for 100TB filesystem testing, so I can't directly compare the speeds to those that I run on physical devices. However I can say that it isn't significantly slower than using small scratch devices... > So what we probably need to do is to have a separate set of tests > using a loopback mount, and perhaps an artificially created file > system which has a large percentage of the blocks in the middle of the > file system busied out, to make efficient testing of these sorts of That's exactly what the --large-fs patch set I posted months ago does for ext4 - it uses fallocate() to fill all but 50GB of the large filesystem without actually writing any data and runs the standard tests in the remaining unused space. However, last time I tested ext4 with this patchset (when I posted the patches months ago), multi-TB preallocation on ext4 was still too slow to make it practical for testing on devices larger than 2-3TB. Perhaps it would make testing 1-2TB ext4 filesystems fast enough that you could do it regularly... Cheers, Dave. -- Dave Chinner david@fromorbit.com