Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754671AbbKLP0b (ORCPT ); Thu, 12 Nov 2015 10:26:31 -0500 Received: from mail-io0-f178.google.com ([209.85.223.178]:33424 "EHLO mail-io0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754404AbbKLP03 (ORCPT ); Thu, 12 Nov 2015 10:26:29 -0500 Subject: Re: [PATCH 0/2] Introduce the request handling for dm-crypt To: Mark Brown , Baolin Wang References: <20151111181813.GD12236@redhat.com> <20151112100422.GM12392@sirena.org.uk> Cc: Mike Snitzer , Alasdair G Kergon , dm-devel@redhat.com, neilb@suse.com, linux-raid@vger.kernel.org, jack@suse.cz, Arnd Bergmann , LKML , keith.busch@intel.com, jmoyer@redhat.com, tj@kernel.org, bart.vanassche@sandisk.com, "Garg, Dinesh" From: Jens Axboe Message-ID: <5644AFA2.6040201@kernel.dk> Date: Thu, 12 Nov 2015 08:26:26 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <20151112100422.GM12392@sirena.org.uk> Content-Type: text/plain; charset=windows-1252; 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: 1704 Lines: 39 On 11/12/2015 03:04 AM, Mark Brown wrote: > On Thu, Nov 12, 2015 at 04:20:41PM +0800, Baolin Wang wrote: > >> 3. perforamence data >> It is just a simple dd test result, and will provide the formal report >> in future. But from the simple test, we can see the improvement. > > It's probably also worth pointing out that Qualcomm have been shipping > an out of tree implementation of this as a separate module in their BSP > (originally written by Danesh Garg who's on this thread): > > https://android.googlesource.com/kernel/msm/+/android-msm-dory-3.10-kitkat-wear/drivers/md/dm-req-crypt.c > > Android now wants to encrypt phones and tablets by default and have been > seeing substantial performance hits as a result, we can try to get > people to share performance data from productionish systems but it might > be difficult. Well, shame on them for developing out-of-tree, looks like they are reaping all the benefits of that. Guys, we need some numbers, enough with the hand waving. There's no point discussing this further until we know how much of a difference it makes to handle X MB chunks instead of Y MB chunks. As was previously stated, unless there's a _substantial_ performance benefit, this patchset isn't going anywhere. If there is a huge benefit, we can look into ways of making it actually work. That may not even be a request interface, it could just be proper utilization of plugging for in-dm bio merging. -- Jens Axboe -- 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/