From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755061AbcIEP44 (ORCPT ); Mon, 5 Sep 2016 11:56:56 -0400 Received: from mailout4.samsung.com ([203.254.224.34]:51494 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752686AbcIEP4x (ORCPT ); Mon, 5 Sep 2016 11:56:53 -0400 X-AuditID: cbfee61a-f78ff6d000001462-b4-57cd95c21d2e From: Bartlomiej Zolnierkiewicz To: Linus Walleij Cc: Mark Brown , Christoph Hellwig , Tejun Heo , Jens Axboe , Paolo Valente , linux-block@vger.kernel.org, "linux-kernel@vger.kernel.org" , Ulf Hansson , Omar Sandoval Subject: Re: [PATCH V2 00/22] Replace the CFQ I/O Scheduler with BFQ Date: Mon, 05 Sep 2016 17:56:35 +0200 Message-id: <17539224.xnQ9OR2lcz@amdc1976> User-Agent: KMail/4.13.3 (Linux/3.13.0-79-generic; KDE/4.13.3; x86_64; ; ) In-reply-to: References: <1470654917-4280-1-git-send-email-paolo.valente@linaro.org> <20160831220949.GD5967@sirena.org.uk> MIME-version: 1.0 Content-transfer-encoding: 7Bit Content-type: text/plain; charset=us-ascii X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrPLMWRmVeSWpSXmKPExsVy+t9jQd1DU8+GG2xuM7JYfbefzWLqwyds FqcnLGKymPJnOZPF3lvaFpd3zWGzOHzvKovFqz97mSx+LT/KaHF8bbgDl8fE5nfsHptXaHlc PlvqsWlVJ5vHnWt72Dw+b5ILYIvisklJzcksSy3St0vgyli65BhLwW2eio9vxRsYe7i6GDk5 JARMJBZ8v8oEYYtJXLi3ng3EFhKYxSix7ExoFyMXkP2VUaJ9+VZmkASbgJXExPZVjCC2iICO RPe2n6wgRcwC15kkTm94zAKSEBZwkWj4BjGJRUBVou3sXLANvAJaEpsvnQNrFhXwkujZ/gjM 5hQIlvh+ZAMrxLZtjBLvJ55nh2gQlPgx+R7YUGYBeYl9+6eyQthaEut3HmeawAh0J0LZLCRl s5CULWBkXsUokVqQXFCclJ5rmJdarlecmFtcmpeul5yfu4kRHA3PpHYwHtzlfohRgINRiYd3 Q+nZcCHWxLLiytxDjBIczEoivJ8nAoV4UxIrq1KL8uOLSnNSiw8xSnOwKInzPv6/LkxIID2x JDU7NbUgtQgmy8TBKdXAOKvU9dUWe/fiYPFp80yrPRYFWb+vcbttNjHu2utJnHfXeH1+zGNT sK0rPEI9fLpF2R/ZO83r69Lm+D6+Uikyy1rlnWmrU+zD4/rscz/7/fu1sa9Nalph4uMJdXLT 47iWd9RU72GRkDzpeOTbOsclG770VzrObXq94Nm/leLzTZ/HvJn1rsDZT4mlOCPRUIu5qDgR AGbc26aCAgAA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Thursday, September 01, 2016 10:39:46 AM Linus Walleij wrote: > On Thu, Sep 1, 2016 at 12:09 AM, Mark Brown wrote: > > > - Do some benchmarks on the current status of the various branches on > > relevant hardware (including trying to convert some of these slower > > devices to blk-mq and seeing what happens). Linus has been working > > on this already in the context of MMC. > > I'm trying to do a patch switching MMC to use blk-mq, so I can > benchmark performance before/after this. > > While we expect mq to perform worse on single-hardware-queue > devices like these, we don't know until we tried, so I'm trying. I did this (switched MMC to blk-mq) some time ago. Patches are extremely ugly and hacky (basically the whole MMC block layer glue code needs to be re-done) so I'm rather reluctant to sharing them yet (to be honest I would like to rewrite them completely before posting). I only did linear read tests (using dd) so far and results that I got were mixed (BTW the hardware I'm doing this work on is Odroid-XU3). Pure block performance under maximum CPU frequency was slightly worse (5-12%) but the CPU consumption was reduced so when CPU was scaled down manually (or ondemand CPUfreq governor was used) blk-mq mode results were better then vanilla ones (up to 10% when CPU was scaled down to minimum frequency and even up to 50% when using ondemand governor - this finding is very interesting and needs to be investigated further). Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics