From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.saout.de ([127.0.0.1]) by localhost (mail.saout.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id zvqxA-WS7BAg for ; Thu, 15 Sep 2011 12:45:49 +0200 (CEST) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mail.saout.de (Postfix) with ESMTP for ; Thu, 15 Sep 2011 12:45:48 +0200 (CEST) Message-ID: <4E71D754.2050506@redhat.com> Date: Thu, 15 Sep 2011 12:45:40 +0200 From: Milan Broz MIME-Version: 1.0 References: <4E70B46C.9050304@gmail.com> <20110914150400.GA18107@tansi.org> <4E70DAB6.2000107@gmail.com> <4E71CA41.1060808@oldum.net> In-Reply-To: <4E71CA41.1060808@oldum.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [dm-crypt] slow read performance, but fast writes? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Nikolay Kichukov Cc: dm-crypt@saout.de, Peter Merhaut On 09/15/2011 11:49 AM, Nikolay Kichukov wrote: > Hi, > this query is best suited for md-raid mailing list as what you measure: > > dd if=/dev/md3 of=/dev/null bs=1M > > does not involve any decryption. You are reading directly from the md device and there is no matter what is actually there. heh. I read that as crypt device and it is MD directly, sorry for confusion. Seems my brain is still in different timezone :) yes, this test has nothing to do with crypt. Anyway, it is interesting that the problem is there even without crypt, perhaps you should ask on linux-raid list then. for badblock - I guess it just submits all IO from one cpu, so only one core is used for encryption in fact. There applies the same what I wrote before. Milan