From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1947427AbcBRRdS (ORCPT ); Thu, 18 Feb 2016 12:33:18 -0500 Received: from down.free-electrons.com ([37.187.137.238]:59940 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1947406AbcBRRdO convert rfc822-to-8bit (ORCPT ); Thu, 18 Feb 2016 12:33:14 -0500 From: Gregory CLEMENT To: Willy Tarreau Cc: "David S. Miller" , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Thomas Petazzoni , Florian Fainelli , Jason Cooper , Andrew Lunn , Sebastian Hesselbarth , linux-arm-kernel@lists.infradead.org, Lior Amsalem , Nadav Haklai , Marcin Wojtas , Simon Guinot , Russell King - ARM Linux , Timor Kardashov , Sebastian Careba Subject: Re: [PATCH v2 net-next 0/8] API set for HW Buffer management References: <1455636823-14470-1-git-send-email-gregory.clement@free-electrons.com> <20160217225958.GA31113@1wt.eu> Date: Thu, 18 Feb 2016 18:32:23 +0100 In-Reply-To: <20160217225958.GA31113@1wt.eu> (Willy Tarreau's message of "Wed, 17 Feb 2016 23:59:58 +0100") Message-ID: <877fi1rkk8.fsf@free-electrons.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Willy, On mer., févr. 17 2016, Willy Tarreau wrote: > Hi Gregory, > > On Tue, Feb 16, 2016 at 04:33:35PM +0100, Gregory CLEMENT wrote: >> Hello, >> >> A few weeks ago I sent a proposal for a API set for HW Buffer >> management, to have a better view of the motivation for this API see >> the cover letter of this proposal: >> http://thread.gmane.org/gmane.linux.kernel/2125152 >> >> Since this version I took into account the review from Florian: >> - The hardware buffer management helpers are no more built by default >> and now depend on a hidden config symbol which has to be selected >> by the driver if needed >> - The hwbm_pool_refill() and hwbm_pool_add() now receive a gfp_t as >> argument allowing the caller to specify the flag it needs. >> - buf_num is now tested to ensure there is no wrapping >> - A spinlock has been added to protect the hwbm_pool_add() function in >> SMP or irq context. >> >> I also used pr_warn instead of pr_debug in case of errors. >> >> I fixed the mvneta implementation by returning the buffer to the pool >> at various place instead of ignoring it. >> >> About the series itself I tried to make this series easier to merge: >> - Squashed "bus: mvenus-mbus: Fix size test for >> mvebu_mbus_get_dram_win_info" into bus: mvebu-mbus: provide api for >> obtaining IO and DRAM window information. >> - Added my signed-otf-by on all the patches as submitter of the series. >> - Renamed the dts patches with the pattern "ARM: dts: platform:" >> - Removed the patch "ARM: mvebu: enable SRAM support in >> mvebu_v7_defconfig" of this series and already applied it >> - Rodified the order of the patches. >> >> In order to ease the test the branch mvneta-BM-framework-v2 is >> available at git@github.com:MISL-EBU-System-SW/mainline-public.git. > > Well, I tested this patch series on top of latest master (from today) > on my fresh new clearfog board. I compared carefully with and without > the patchset. My workload was haproxy receiving connections and forwarding > them to my PC via the same port. I tested both with short connections > (HTTP GET of an empty file) and long ones (1 MB or more). No trouble > was detected at all, which is pretty good. I noticed a very tiny > performance drop which is more noticeable on short connections (high > packet rates), my forwarded connection rate went down from 17500/s to > 17300/s. But I have not checked yet what can be tuned when using the > BM, nor did I compare CPU usage. I remember having run some tests in > the past, I guess it was on the XP-GP board, and noticed that the BM > could save a significant amount of CPU and improve cache efficiency, > so if this is the case here, we don't really care about a possible 1% > performance drop. > > I'll try to provide more results as time permits. > > In the mean time if you want (or plan to submit a next batch), feel > free to add a Tested-by: Willy Tarreau . Great! thanks for testing. Gregory > > cheers, > Willy > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com