From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B2FCC04AB1 for ; Mon, 13 May 2019 09:59:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 61D0C21479 for ; Mon, 13 May 2019 09:59:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728313AbfEMJ7X (ORCPT ); Mon, 13 May 2019 05:59:23 -0400 Received: from relay12.mail.gandi.net ([217.70.178.232]:43627 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727915AbfEMJ7W (ORCPT ); Mon, 13 May 2019 05:59:22 -0400 Received: from localhost (unknown [80.215.106.0]) (Authenticated sender: maxime.ripard@bootlin.com) by relay12.mail.gandi.net (Postfix) with ESMTPSA id 5012F200006; Mon, 13 May 2019 09:59:16 +0000 (UTC) Date: Mon, 13 May 2019 11:59:16 +0200 From: Maxime Ripard To: Uenal Mutlu Cc: Jens Axboe , Chen-Yu Tsai , linux-ide@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com, linux-amarula@amarulasolutions.com, Jagan Teki , Pablo Greco , Mark Rutland , Oliver Schinagl , Linus Walleij , Hans de Goede , FUKAUMI Naoki , Andre Przywara , Stefan Monnier Subject: Re: [RFC PATCH v2 RESEND] drivers: ata: ahci_sunxi: Increased SATA/AHCI DMA TX/RX FIFOs Message-ID: <20190513095916.yyjdtueeefkf4v4b@flea> References: <20190512205954.18435-1-um@mutluit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190512205954.18435-1-um@mutluit.com> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Sun, May 12, 2019 at 10:59:54PM +0200, Uenal Mutlu wrote: > Increasing the SATA/AHCI DMA TX/RX FIFOs (P0DMACR.TXTS and .RXTS, ie. > TX_TRANSACTION_SIZE and RX_TRANSACTION_SIZE) from default 0x0 each > to 0x3 each, gives a write performance boost of 120 MiB/s to 132 MiB/s > from lame 36 MiB/s to 45 MiB/s previously. > Read performance is about 200 MiB/s. > [tested on SSD using dd bs=2K/4K/8K/12K/16K/24K/32K: peak-perf at 12K]. > > Tested on the Banana Pi R1 (aka Lamobo R1) and Banana Pi M1 SBCs > with Allwinner A20 32bit-SoCs (ARMv7-a / arm-linux-gnueabihf). > These devices are RaspberryPi-like small devices. > > This problem of slow SATA write-speed with these small devices lasts now > for more than 5 years. Many commentators throughout the years wrongly > assumed the slow write speed was a hardware limitation. This patch finally > solves the problem, which in fact was just a hard-to-fix software problem > (b/c of lack of documentation by the SoC-maker Allwinner Technology). > > RFC: Since more than about 25 similar SBC/SoC models do use the > ahci_sunxi driver, users are encouraged to test it on all the > affected boards and give feedback. > > Lists of the affected sunxi and other boards and SoCs with SATA using > the ahci_sunxi driver: > $ grep -i -e "^&ahci" arch/arm/boot/dts/sun*dts > and http://linux-sunxi.org/SATA#Devices_with_SATA_ports > See also http://linux-sunxi.org/Category:Devices_with_SATA_port > > Patch v2: > - Commented the patch in-place in ahci_sunxi.c > - With bs=12K and no conv=... passed to dd, the write performance > rises further to 132 MiB/s > - Changed MB/s to MiB/s > - Posted the story behind the patch: > http://lkml.iu.edu/hypermail/linux/kernel/1905.1/03506.html > - Posted a dd test script to find optimal bs, and some results: > https://bit.ly/2YoOzEM > > Patch v1: > - States bs=4K for dd and a write performance of 120 MiB/s > > Signed-off-by: Uenal Mutlu Acked-by: Maxime Ripard Just a minor nitpick though, the part starting with RFC: and with the version changelog should be after the --- below so that it doesn't get applied as part of the commit log. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com