From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaegeuk Kim Subject: Re: write performance difference 3.18.21/4.2.1 Date: Fri, 25 Sep 2015 11:26:46 -0700 Message-ID: <20150925182646.GB6998@jaegeuk-mac02> References: <20150924175131.GC40291@jaegeuk-mac02> <20150924182836.GD40291@jaegeuk-mac02> <20150925065057.GA2638@schmorp.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1ZfXhw-0000L2-O8 for linux-f2fs-devel@lists.sourceforge.net; Fri, 25 Sep 2015 18:26:56 +0000 Received: from mail.kernel.org ([198.145.29.136]) by sog-mx-2.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1ZfXhv-00040e-HJ for linux-f2fs-devel@lists.sourceforge.net; Fri, 25 Sep 2015 18:26:56 +0000 Content-Disposition: inline In-Reply-To: <20150925065057.GA2638@schmorp.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: Marc Lehmann Cc: linux-f2fs-devel@lists.sourceforge.net On Fri, Sep 25, 2015 at 08:50:57AM +0200, Marc Lehmann wrote: > On Thu, Sep 24, 2015 at 11:28:36AM -0700, Jaegeuk Kim wrote: > > One thing that we can try is to run the latest f2fs source in v3.18. > > This branch supports f2fs for v3.18. > > Ok, please bear with me, the last time I built my own kernel was during > the 2.4 timeframe, and this is a ubuntu kernel. What I did is this: > > git clone -b linux-3.18 git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git > cd f2fs/fs/f2fs > rsync -avPR include/linux/f2fs_fs.h include/trace/events/f2fs.h /usr/src/linux-headers-3.18.21-031821/. > make -C /lib/modules/3.18.21-031821-generic/build/ M=$PWD modules modules_install > > I then rmmod f2fs/insmod the resulting module, and tried to mount my > existing f2fs fs for a quick test, but got a null ptr exception on "mount": > > http://ue.tst.eu/e4628dcee97324e580da1bafad938052.txt > > Probably caused me not building a full kernel, but recreating how ubuntu > build their kernels on a debian system isn't something I look forward to. Please, pull the v3.18 again. I rebased it. :-( > > > For example, if I can represent blocks like: > [number of logs discussion] > > Thanks for this explanation - two logs doesn't look so bad, from a > locality viewpoint (not a big issue for flash, but a big issue for > rotational devices - I also realised I can't use dmcache as dmcache, even > in writethrough mode, writes back all data after an unclean shutdown, > which would positively kill the disk). > > Since whatever speed difference I saw with two logs wasn't big, you > completely sold me on 6 logs, or 4 (especially if it seepds up the gc, > which I haven't much tested yet). Two logs was merely a test anyway (the > same with no_heap, I don't know what it does, but I thought it is worth > a try, as metadata + data nearer together is better than having them at > opposite ends of the log or so). If the section size is pretty large, no_heap would be enough. The original intention was to provide more contiguous space for data only so that a big file could have a large extent instead of splitting by its metadata. > > -- > The choice of a Deliantra, the free code+content MORPG > -----==- _GNU_ http://www.deliantra.net > ----==-- _ generation > ---==---(_)__ __ ____ __ Marc Lehmann > --==---/ / _ \/ // /\ \/ / schmorp@schmorp.de > -=====/_/_//_/\_,_/ /_/\_\ ------------------------------------------------------------------------------