From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932794Ab0CLNMU (ORCPT ); Fri, 12 Mar 2010 08:12:20 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36676 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756555Ab0CLNMR (ORCPT ); Fri, 12 Mar 2010 08:12:17 -0500 Message-ID: <4B9A3DAC.3020008@redhat.com> Date: Fri, 12 Mar 2010 14:12:12 +0100 From: Milan Broz User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.8) Gecko/20100227 Lightning/1.0b1 Thunderbird/3.0.3 MIME-Version: 1.0 To: Matthias Schniedermeyer CC: Mathias Buren , linux-kernel@vger.kernel.org Subject: Re: RAID + LUKS + LVM performance References: <20100311173604.GA17659@citd.de> <20100312120643.GA26020@citd.de> In-Reply-To: <20100312120643.GA26020@citd.de> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/12/2010 01:06 PM, Matthias Schniedermeyer wrote: > Using one of the Westmere Core i5-6XX, which support AES-NI, should get > you better performance (if supported by krcyptd), altough you loose 2 > cores as onyl have 2. But i don't know what kind of performance > improvement (if any) AES-NI provides. > Or you wait a few weeks and buy on Core I7-980X with 6 core and AES-NI. dm-crypt uses whatever is implemented in cryptoAPI, AES-NI of course works when you have proper modules loaded. The main reason why dm-crypt is single-threaded is that all these new crypto accelerators uses asynchronous crypto API, so if hw allows parallel operation it can use it already. (dm-crypt submits all sectors in bio as separate asynchronous crypto requests). But note: single threaded per volume - if you have LVM with multiple encrypted LVs - every LV have its own thread. If we build another multi-core(thread) processing in dm-crypt, it can help on multi-core CPU but complicate things otherwise. (I tried simple implementation and abandoned it, I would prefer if cryptoAPI can do some parallel processing itself here. That question was discussed several times on dm-crypt mailing list.) Anyway, only two real-world examples, where one thread in dm-crypt can cause real problems with speed - dm-crypt over fast RAID(5) - dm-crypt over fast SSD. And many users of these configurations have now AES-NI acceleration. Milan -- mbroz@redhat.com