From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shaohua Li Subject: Re: [patch 0/7] Add TRIM support for raid linear/0/1/10 Date: Thu, 15 Mar 2012 10:39:44 +0800 Message-ID: References: <20120312030412.375458948@fusionio.com> <4F5EFEB6.4060402@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Holger Kiehl Cc: "linux-kernel@vger.kernel.org" , "linux-raid@vger.kernel.org" , "neilb@suse.de" , "axboe@kernel.dk" List-Id: linux-raid.ids 2012/3/15 Holger Kiehl : > On Wed, 14 Mar 2012, Shaohua Li wrote: > >> Maybe the discard runs slow with small size request in the disk. >> please drop patch "blk: add plug for blkdev_issue_discard" and try again. >> Since >> we can't do merge, the plug just introduces latency. >> > Tried again without the patch applied, but there is only a very small > performance increase (520->600 agains 4000 fps without discard). > > The benchmark creates lots of small files (2 KiB) and deletes them again. > > >> if it doesn't help, please capture a blktrace when you do the benchmark >> and >> send it to me. >> > Ok, I will do this tomorrow. Need some sleep :-) > > Thanks for your work on supporting discard in MD! I tried your benchmark, create 2000k 2k files and delete them and follows a sync. the discard runs pretty fast for both raid 0/1. So can't reproduce the issue. I'm using a fusionio card though. I'm afraid nothing I can do till get you blktrace. Thanks, Shaohua