From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [RFC PATCH v6 0/5] treewide: improve R-Car SDHI performance Date: Thu, 13 Jun 2019 21:36:28 +0200 Message-ID: <20190613193628.GA6863@kunai> References: <1560421215-10750-1-git-send-email-yoshihiro.shimoda.uh@renesas.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============7359102268517268240==" Return-path: In-Reply-To: <1560421215-10750-1-git-send-email-yoshihiro.shimoda.uh-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Yoshihiro Shimoda Cc: axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, linux-renesas-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ulf.hansson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, linux-mmc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, wsa+renesas-jBu1N2QxHDJrcw3mvpCnnVaTQe2KTcn/@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, hch-jcswGhMUV9g@public.gmane.org List-Id: linux-mmc@vger.kernel.org --===============7359102268517268240== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="k+w/mQv8wyuph6w0" Content-Disposition: inline --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-- --===============7359102268517268240== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============7359102268517268240==--