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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 5A22DC38A30 for ; Wed, 22 Apr 2020 06:43:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28651206E9 for ; Wed, 22 Apr 2020 06:43:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Gb7ek6Yt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726609AbgDVGnh (ORCPT ); Wed, 22 Apr 2020 02:43:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726041AbgDVGng (ORCPT ); Wed, 22 Apr 2020 02:43:36 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A861DC03C1A6; Tue, 21 Apr 2020 23:43:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=n7bSWCy+yjEVd5/eEit7zxHT7ampFTjRw0vL4VxyfNM=; b=Gb7ek6Ytu/i+eVBcw6iQxNRQEX lFgqHAf+9baTdGXdabiAr/PxaKU/oTW7Od3ihMdBHDjmsw2H9DdSVYQ4FcFp/AXzBP9uD0vzsacV/ tapmfrVksjcwdz0iIZuA5IBGrntQKC4uadFOFu+jhE2oUFc5Y8eNtHx8OPg8ZOGvMM5H8XOFUjtYb jnV/wJiasU6SV/kWNNNaYsCWbiJMLiM6eA8QR1Tyjvqq3D/oU/b1o+4SsGGVGBp0y5/Uswp+dlj1Z K7xwQEHwC3D/bE1rZnu8fqFKkgIFx9hPGXQSQ3wxr3r/2mZXpv9GXLabkoKPcyLT6Yw6wjLd+2wkO UKrLSXjQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jR96S-0004JA-9L; Wed, 22 Apr 2020 06:43:24 +0000 Date: Tue, 21 Apr 2020 23:43:24 -0700 From: Christoph Hellwig To: huobean@gmail.com Cc: alim.akhtar@samsung.com, avri.altman@wdc.com, asutoshd@codeaurora.org, jejb@linux.ibm.com, martin.petersen@oracle.com, stanley.chu@mediatek.com, beanhuo@micron.com, bvanassche@acm.org, tomas.winkler@intel.com, cang@codeaurora.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/5] UFS Host Performance Booster (HPB v1.0) driver Message-ID: <20200422064324.GF20318@infradead.org> References: <20200416203126.1210-1-beanhuo@micron.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200416203126.1210-1-beanhuo@micron.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 16, 2020 at 10:31:21PM +0200, huobean@gmail.com wrote: > From: Bean Huo > > Hi, > I disclose my development/changes on UFS HPB (UFS Host Performance Booster) to > the community, as this would enable more UFS developers to test and start an > iterative review and update process. > > The HPB is defined in Jedec Standard Universal Flash (UFS) Host Performance > Booster (HPB) Extension Version 1.0, which is designed to improve read > performance by utilizing the host side memory. Based on our testing, the HPB > can increase the random read performance by up to about 46% in the random read. > > The original HPB driver is from [1]. Based on it, I did optimizations, > simplifications, fixed reliability issues, implemented HPB host control mode > and make it much more readable. which's pushed to here [2] as V1. > > To avoid touching the traditional SCSI core, the HPB driver in this series HPB > patch chooses to develop under SCSI sub-system layer, and sits the same layer > with UFSHCD. At the same time, to minimize changes to UFSHCD driver, the HPB > driver submits its HPB READ BUFFER and HPB WRITE BUFFER requests to the scsi > device->request_queueu to execute, rather than that directly go through > raw UPIU request path. This feature is completley broken, and rather dangerous due to feeding "physical" addresses looked up by the host in. I do not think we should support something that broken in Linux. Independent of that using two requests in the I/O path is not going to fly either. The whole thing seems like an exercise in benchmarketing.