From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933152AbdBQKh3 convert rfc822-to-8bit (ORCPT ); Fri, 17 Feb 2017 05:37:29 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:36278 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932326AbdBQKh1 (ORCPT ); Fri, 17 Feb 2017 05:37:27 -0500 From: Gregory CLEMENT To: Jisheng Zhang Cc: , , , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH net-next v2 0/2] net: mvneta: improve rx performance References: <20170217100233.2325-1-jszhang@marvell.com> Date: Fri, 17 Feb 2017 11:37:21 +0100 In-Reply-To: <20170217100233.2325-1-jszhang@marvell.com> (Jisheng Zhang's message of "Fri, 17 Feb 2017 18:02:31 +0800") Message-ID: <87shndayse.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 Jisheng, On ven., févr. 17 2017, Jisheng Zhang wrote: > In hot code path such as mvneta_rx_hwbm() and mvneta_rx_swbm(), we may > access fields of rx_desc. The rx_desc is allocated by > dma_alloc_coherent, it's uncacheable if the device isn't cache > coherent, reading from uncached memory is fairly slow. Did you test it with HWBM support? I am not sure ti will work in this case. Gregory > > patch1 reuses the read out status to getting status field of rx_desc > again. > > patch2 uses cacheable memory to store the rx buffer DMA address. > > We get the following performance data on Marvell BG4CT Platforms > (tested with iperf): > > before the patch: > recving 1GB in mvneta_rx_swbm() costs 149265960 ns > > after the patch: > recving 1GB in mvneta_rx_swbm() costs 1421565640 ns > > We saved 4.76% time. > > RFC: can we do similar modification for tx? If yes, I can prepare a v2. > > > Basically, these two patches do what Arnd mentioned in [1]. > > Hi Arnd, > > I added "Suggested-by you" tag, I hope you don't mind ;) > > Thanks > > [1] https://www.spinics.net/lists/netdev/msg405889.html > > Since v1: > - correct the performance data typo > > Jisheng Zhang (2): > net: mvneta: avoid getting status from rx_desc as much as possible > net: mvneta: Use cacheable memory to store the rx buffer DMA address > > drivers/net/ethernet/marvell/mvneta.c | 36 ++++++++++++++++++++--------------- > 1 file changed, 21 insertions(+), 15 deletions(-) > > -- > 2.11.0 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com