From mboxrd@z Thu Jan 1 00:00:00 1970 From: Milan Broz Subject: Re: dm_crypt: very low performance of random IO operations Date: Tue, 07 Sep 2010 22:06:35 +0200 Message-ID: <4C869B4B.706@redhat.com> References: <4C80B1B9.6040809@gmail.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4C80B1B9.6040809@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids On 09/03/2010 10:28 AM, Yakov Hrebtov wrote: > I'm experirncing problems with performance of random IO operations of > dm_crypt-encrypted devices. > Sequential IO is good (using AES-NI gives almost no difference comparing with > unencrypted device), but random IO is poor comparing with unencrypted devices. Just info for the list - this mail is duplicate of https://bugzilla.kernel.org/show_bug.cgi?id=17892 so let's use this BZ to track it. I have some ideas how to improve it, but the change must follow patches which are currently waiting for upstream inclusion. (Actually the per-cpu thread patches helps in this case too as side effect.) Milan