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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9237C7EE22 for ; Thu, 11 May 2023 10:35:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237149AbjEKKfV convert rfc822-to-8bit (ORCPT ); Thu, 11 May 2023 06:35:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236816AbjEKKfU (ORCPT ); Thu, 11 May 2023 06:35:20 -0400 Received: from lithops.sigma-star.at (lithops.sigma-star.at [195.201.40.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7030EA7; Thu, 11 May 2023 03:35:17 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id E8988615C9F5; Thu, 11 May 2023 12:35:04 +0200 (CEST) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id LDkxuyXXLkqL; Thu, 11 May 2023 12:35:04 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 545BD61B8B4D; Thu, 11 May 2023 12:35:04 +0200 (CEST) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id u3mttOWBUBDr; Thu, 11 May 2023 12:35:04 +0200 (CEST) Received: from lithops.sigma-star.at (lithops.sigma-star.at [195.201.40.130]) by lithops.sigma-star.at (Postfix) with ESMTP id 30A9B615C9F5; Thu, 11 May 2023 12:35:04 +0200 (CEST) Date: Thu, 11 May 2023 12:35:04 +0200 (CEST) From: Richard Weinberger To: Christian Loehle Cc: Biju Das , linux-mmc , linux-renesas-soc , wsa+renesas , ulf hansson Message-ID: <673489738.9276814.1683801304117.JavaMail.zimbra@nod.at> In-Reply-To: <94f03374781b4e978a39699815b21803@hyperstone.com> References: <1674847756.113858.1681762124503.JavaMail.zimbra@nod.at> <522326845.127346.1681805484949.JavaMail.zimbra@nod.at> <1186364892.150923.1681819136247.JavaMail.zimbra@nod.at> <1273293952.226564.1682003880265.JavaMail.zimbra@nod.at> <398e244a4d3746f1bd7b4c32d1ea70e3@hyperstone.com> <615854031.8233438.1683631700226.JavaMail.zimbra@nod.at> <94f03374781b4e978a39699815b21803@hyperstone.com> Subject: Re: Poor write performance to boot area using rcar-gen3-sdhi MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Originating-IP: [195.201.40.130] X-Mailer: Zimbra 8.8.12_GA_3807 (ZimbraWebClient - FF97 (Linux)/8.8.12_GA_3809) Thread-Topic: Poor write performance to boot area using rcar-gen3-sdhi Thread-Index: jiFrfBZIr7HKS7MkHilHFl02Bun/Q/AMgGyAaB0PmjP8vxGocEw2ct+x/Z5ZwOAvOJ8Zmh6KUsXr/ZciBcB4n5SQpfxaAwsASMB9OoY= Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org ----- Ursprüngliche Mail ----- > Von: "Christian Loehle" >> While u-boot does basically all IO with one op code, Linux's writeback via page >> cache writes 4k wise which leads to catastrophic performance. >> Using O_DIRECT mitigates the issue, though. > > Interesting, without having tried it out I would expect the 4k writebacks to be > merged to a bigger IO, too? Given that they are filled sequentially, which is > the case. > But good that you got it working. > If I find the time I will play with it a bit. I think due to the nature of rcar-gen3-sdhi merging of these BIOs is not possible. There seems to be support for some variants, though: https://elinux.org/R-Car/Merging-MMC-block-requests Not sure whether I find the time to dig down that rabbit whole too. ;-) Thanks, //richard