Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757614Ab0FBHwJ (ORCPT ); Wed, 2 Jun 2010 03:52:09 -0400 Received: from mga06.intel.com ([134.134.136.21]:51074 "EHLO orsmga101.jf.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753380Ab0FBHwI (ORCPT ); Wed, 2 Jun 2010 03:52:08 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,346,1272870000"; d="scan'208";a="523208739" Message-ID: <4C060D9F.3050600@linux.intel.com> Date: Wed, 02 Jun 2010 09:51:59 +0200 From: Andi Kleen User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.1.9) Gecko/20100317 Thunderbird/3.0.4 MIME-Version: 1.0 To: Mikulas Patocka CC: Herbert Xu , device-mapper development , linux-kernel@vger.kernel.org, agk@redhat.com Subject: Re: [dm-devel] [PATCH] DM-CRYPT: Scale to multiple CPUs References: <20100531160425.GA20344@basil.fritz.box> <20100601043901.GA25693@gondor.apana.org.au> <20100602051403.GA5784@gondor.apana.org.au> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 781 Lines: 23 >> >>> It is pointless to track the submitting CPU. >> >> No you are wrong. > > For what? For avoiding cache bounces? But the encrypting is > order-of-magnitude slower than memory speed. On a system with reasonably fast CPUs it's fastest to just stay on your current CPU, don't try to talk to other CPUs, avoid communication, just get the work done ASAP. But make sure you can do this on multiple CPUs at the same time. With AES-NI this becomes even more pronounced because it effectively makes the CPU faster for encryption. -andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/