From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dominik Brodowski Subject: Re: direct-io regression [Was: How to track down abysmal performance ata - raid1 - crypto - vg/lv - xfs] Date: Thu, 5 Aug 2010 18:35:19 +0200 Message-ID: <20100805163519.GA6604@comet.dominikbrodowski.net> References: <20100805123649.GA18672@dhcp231-156.rdu.redhat.com> <20100805113240.GA29846@think> <20100805153519.GA7242@comet.dominikbrodowski.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20100805153519.GA7242@comet.dominikbrodowski.net> Sender: linux-raid-owner@vger.kernel.org To: Chris Mason , josef@redhat.com, Valdis.Kletnieks@vt.edu, Michael Monnerie , Christoph Hellwig , linux List-Id: linux-raid.ids Small correction: On Thu, Aug 05, 2010 at 05:35:19PM +0200, Dominik Brodowski wrote: > With this fix, I get proper speeds when doing dio reads from > /dev/mapper/vg0-*_crypt; see the 17.3 MB/s above. Most strangely, > also accesing /dev/mapper/vg0-* (un-encrypted) and the raw > device at /dev/sda* speeds up (to up to 28 MB/s). Was only seeing around > 16 to 18 MB/s without this patch for unencrypted access. The speed-up of the unencrypted access (18 -> 28 MB/s) is caused by using a different configuration for kernel 2.6.35; and seems to be unrelated to your patch. Will try to track down which config option is the culprit. kernel, dmcrypt? | good config | bad config ------------------------------------------------- patched 2.6.35, dmcrypt ~ 18 MB/s ~ 13 MB/s patched 2.6.35 ~ 28 MB/s ~ 18 MB/s ------------------------------------------------- plain 2.6.35, dmcrypt ~ 3 MB/s ~ 3 MB/s plain 2.6.35 ~ 16 MB/s Best, Dominik