Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932485AbbKMCH1 (ORCPT ); Thu, 12 Nov 2015 21:07:27 -0500 Received: from mail-yk0-f178.google.com ([209.85.160.178]:36023 "EHLO mail-yk0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932258AbbKMCHZ (ORCPT ); Thu, 12 Nov 2015 21:07:25 -0500 MIME-Version: 1.0 In-Reply-To: <5644AFA2.6040201@kernel.dk> References: <20151111181813.GD12236@redhat.com> <20151112100422.GM12392@sirena.org.uk> <5644AFA2.6040201@kernel.dk> Date: Fri, 13 Nov 2015 10:07:25 +0800 Message-ID: Subject: Re: [PATCH 0/2] Introduce the request handling for dm-crypt From: Baolin Wang To: Jens Axboe Cc: Mark Brown , Mike Snitzer , Alasdair G Kergon , dm-devel@redhat.com, neilb@suse.com, linux-raid@vger.kernel.org, Jan Kara , Arnd Bergmann , LKML , keith.busch@intel.com, jmoyer@redhat.com, tj@kernel.org, bart.vanassche@sandisk.com, "Garg, Dinesh" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1957 Lines: 57 On 12 November 2015 at 23:26, Jens Axboe wrote: > 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. That's fair enough and we will provide the performance data to measure the patchset. > > 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. Make sense. Thanks. > > -- > Jens Axboe > -- Baolin.wang Best Regards -- 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/