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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 7D5D5C04AA7 for ; Mon, 13 May 2019 13:54:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59534208CA for ; Mon, 13 May 2019 13:54:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729142AbfEMNyX (ORCPT ); Mon, 13 May 2019 09:54:23 -0400 Received: from sauhun.de ([88.99.104.3]:40754 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729040AbfEMNyW (ORCPT ); Mon, 13 May 2019 09:54:22 -0400 Received: from localhost (p54B3324F.dip0.t-ipconnect.de [84.179.50.79]) by pokefinder.org (Postfix) with ESMTPSA id A950E3E42F7; Mon, 13 May 2019 15:54:20 +0200 (CEST) Date: Mon, 13 May 2019 15:54:20 +0200 From: Wolfram Sang To: Yoshihiro Shimoda Cc: "ulf.hansson@linaro.org" , "wsa+renesas@sang-engineering.com" , "linux-mmc@vger.kernel.org" , "linux-renesas-soc@vger.kernel.org" Subject: Re: [PATCH v2 2/2] mmc: renesas_sdhi: use multiple segments if possible Message-ID: <20190513135420.GB20443@kunai> References: <1557721744-30545-1-git-send-email-yoshihiro.shimoda.uh@renesas.com> <1557721744-30545-3-git-send-email-yoshihiro.shimoda.uh@renesas.com> <20190513090054.GA15744@kunai> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="TakKZr9L6Hm6aLOc" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org --TakKZr9L6Hm6aLOc Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Shimoda-san, > > > That also means, for the sys-dmac and Gen2, we then use 512 for the > > > IOMMU case and 32 (default TMIO value) for the non IOMMU case. My > > > understanding is that SYS DMAC can handle 512 in both cases. Maybe it > > > makes sense then to make an incremental patch setting the max_segs va= lue > > > explicitly to 512 in the sys-dmac driver for Gen2? > >=20 > > I also think SYS DMAC can handle 512 segments. However, I'm not sure > > it can improve the performance or not though. Anyway, an incremental pa= tch > > makes sense if needed, I think. >=20 > I measured the performance on R-Car H2 Lager. It seems 512 segments impro= ve > the sequential input to 5%. May I make an incremental patch on the patch = series? > What do you think? Cool! I didn't expect that much of a performance improvement. My main concern was understandable code because there was no "real reason" that we once use 32 and once 512. But if it causes even a performance improvement, even better :) Yes, an incremental patch is a good idea. Thanks for the work, Wolfram --TakKZr9L6Hm6aLOc Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAlzZdwwACgkQFA3kzBSg KbYZlQ//d8HN99ysATnSIUFh/qOo7UMZw4lDeHTwqPUYMEEvzWBMJ1ZOrCpDMqXc lx53Z/Tj8nYR7Fwe5UOTL33EIvDz5wjFg0IsF05dBTf+WN1i8Z9hSAtqkvBuMWYR nMbK4TGGAwNDKrWaqlxMq8iZsmz6v8EVU3flcNBXue9cvUc0CZo+2aYgT+lSlHQ4 bp/Jm73jXIJTCI1fkZZtvkK4xpb5KvwHd6mhvBidpkJoMBDwkLj50LQYBSFy0Uiu /n6x+seX3xcdcWhr3JnILvcdna8PpLuNBy3CNWn3McyJ6h5Ovx/vrhtNCfDateR6 9YMrF1POwCNujbiK7JAw5D3T2b2MVcCMaUK6mD6Z1bRC3V/Q5v9BfvExwucwH8cc tGUwIrTXMS6kjpgnynV1LMkMbeLozmOwA+FChv3xGTaB/QL6hZ2UQ5jR8f5TQof8 DXPSQ3HNdnASyOZWdOyPTTEcpSdk5EL3OwlImk4i4jq9YfLP3E3H+xSwxbp2IOb+ wMkqHZ5rJhzTHBfLEtuL5BqMMptwx1U56UUfTsBTdTkZNi85anYtYwZmWUHh8Z/W BPpKvAYlUJ9aO/eYkfvmzO/FkA2qppRbaPy7OrX12PhHkeeV7acAH7YJa7XYaxBe K97oqnHuyRbRj0jYPiDM//XIWYTpXduBD5wMWRGwpcTsmykbyGE= =/6WD -----END PGP SIGNATURE----- --TakKZr9L6Hm6aLOc--