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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT 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 566D1C31E45 for ; Thu, 13 Jun 2019 19:36:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3603B21721 for ; Thu, 13 Jun 2019 19:36:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726969AbfFMTgb (ORCPT ); Thu, 13 Jun 2019 15:36:31 -0400 Received: from sauhun.de ([88.99.104.3]:44244 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725809AbfFMTgb (ORCPT ); Thu, 13 Jun 2019 15:36:31 -0400 Received: from localhost (p5486CF99.dip0.t-ipconnect.de [84.134.207.153]) by pokefinder.org (Postfix) with ESMTPSA id 61EBA4A127B; Thu, 13 Jun 2019 21:36:29 +0200 (CEST) Date: Thu, 13 Jun 2019 21:36:28 +0200 From: Wolfram Sang To: Yoshihiro Shimoda Cc: joro@8bytes.org, axboe@kernel.dk, ulf.hansson@linaro.org, wsa+renesas@sang-engineering.com, hch@lst.de, iommu@lists.linux-foundation.org, linux-block@vger.kernel.org, linux-mmc@vger.kernel.org, linux-renesas-soc@vger.kernel.org Subject: Re: [RFC PATCH v6 0/5] treewide: improve R-Car SDHI performance Message-ID: <20190613193628.GA6863@kunai> References: <1560421215-10750-1-git-send-email-yoshihiro.shimoda.uh@renesas.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="k+w/mQv8wyuph6w0" Content-Disposition: inline In-Reply-To: <1560421215-10750-1-git-send-email-yoshihiro.shimoda.uh@renesas.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org --k+w/mQv8wyuph6w0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 13, 2019 at 07:20:10PM +0900, Yoshihiro Shimoda wrote: > This patch series is based on iommu.git / next branch. >=20 > Since SDHI host internal DMAC of the R-Car Gen3 cannot handle two or > more segments, the performance rate (especially, eMMC HS400 reading) > is not good. However, if IOMMU is enabled on the DMAC, since IOMMU will > map multiple scatter gather buffers as one contignous iova, the DMAC can > handle the iova as well and then the performance rate is possible to > improve. In fact, I have measured the performance by using bonnie++, > "Sequential Input - block" rate was improved on r8a7795. >=20 > To achieve this, this patch series modifies IOMMU and Block subsystem > at first. Since I'd like to get any feedback from each subsystem whether > this way is acceptable for upstream, I submit it to treewide with RFC. >=20 > Changes from v5: > - Almost all patches are new code. > - [4/5 for MMC] This is a refactor patch so that I don't add any > {Tested,Reviewed}-by tags. > - [5/5 for MMC] Modify MMC subsystem to use bigger segments instead of > the renesas_sdhi driver. > - [5/5 for MMC] Use BLK_MAX_SEGMENTS (128) instead of local value > SDHI_MAX_SEGS_IN_IOMMU (512). Even if we use BLK_MAX_SEGMENTS, > the performance is still good. Thanks for your hard work, Shimoda-san! I may not be the biggest DMA, IOMMU, and block layer expert, but I really like how this simplifies the SDHI driver and enhances the MMC core. So, I'll add my two cents to the patches although I can't really comment on the main functionality. --k+w/mQv8wyuph6w0 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAl0CpbgACgkQFA3kzBSg Kbb6fhAAsdfuCLxXS4xDUphPESkF+gt9xfaK1rX85NT4mPOnCRA7AMdH0rzSAboF MFBO01ZS1+9P5SOaOuKArFD1rDkk9t41Hp+AEcsyGZMt47QlwvXakNaQeoGVLUuu 9kex9v8bpMgXjDS9B7CFcbWnLvEjEyysBYBVRMpppo1UwfIwKoQFZAzKJkodXGpE i5HOkl+woaQVUDgNnnKEVbAmSmCJ7H8Nb4CvzRk14i5GK2UYUi9ql9B4Fro4tsgM dqSlNzb9x/70ajG5EYGv5+E+pA8u3du9hNLzsm7PoFWCUIPa5n74aQC4CpMcjUao FqPHfzcT3Mg8fk2K7u6riIaQAO7c/sYJ4quv547+cPTyPoAs290HqRZqH413C9wr hQtNlC2g7j+6hgrkzyoesGKl0zpiPdW3TKQ17tDGoCipGKDwQGptKunqWFbDY90h UJdgHWAo/kjy+pAGlutoy5bPdEbYYpxgHCgCrOaN0fzV7qKg7N1gfvRCNJSS0U9d gNzLc4vE+d3a2jPq90LRNxpBoUgB/iuJBIEhZcTycIMjUBrWQ8ikClrFBMHkLEds slSs6vzgUDcqOBSVQUVAif92fBeOUONnGbwOBx/r6x8LFIpG5h3gw0rRr9mF6Ppo 48Oi8LWLrkZ3ZSjfNyQMaUi4rPwEqULxuhqN7MZIAVUZk3f9L5s= =tqtY -----END PGP SIGNATURE----- --k+w/mQv8wyuph6w0--