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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 12F8EC433FE for ; Tue, 8 Dec 2020 04:18:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E201C21E92 for ; Tue, 8 Dec 2020 04:18:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726969AbgLHESp (ORCPT ); Mon, 7 Dec 2020 23:18:45 -0500 Received: from mailout2.samsung.com ([203.254.224.25]:49122 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726777AbgLHESo (ORCPT ); Mon, 7 Dec 2020 23:18:44 -0500 Received: from epcas3p3.samsung.com (unknown [182.195.41.21]) by mailout2.samsung.com (KnoxPortal) with ESMTP id 20201208041802epoutp02ad72ef1a2ef3dda6402802d29016644c~OosSazs1I2802328023epoutp02E for ; Tue, 8 Dec 2020 04:18:02 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout2.samsung.com 20201208041802epoutp02ad72ef1a2ef3dda6402802d29016644c~OosSazs1I2802328023epoutp02E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1607401082; bh=bNcO0L7f6HW9trLGLjRuh+5Y5IE2mspFwgJfTwfn9TU=; h=Subject:Reply-To:From:To:CC:In-Reply-To:Date:References:From; b=ofVhsodbZafGyPcVg8JESrOUpcPdsheMxt+MTmnPYPKcR/1IqhBSRawijnvZuJSx/ NIhPr9dbu8M4e07GyMl/4kleqqegF/IdTUvqQhzLu2NWfXtwUhnqSCH1ucwDlKPYYU 5lxfh1EBZipFebpNsNjvn4rFdg2Hkejro8zoVBKI= Received: from epsnrtp2.localdomain (unknown [182.195.42.163]) by epcas3p3.samsung.com (KnoxPortal) with ESMTP id 20201208041801epcas3p3d9219a9d0c1a572936a60e062cead918~OosR3HcpY2756127561epcas3p3k; Tue, 8 Dec 2020 04:18:01 +0000 (GMT) Received: from epcpadp4 (unknown [182.195.40.18]) by epsnrtp2.localdomain (Postfix) with ESMTP id 4Cqn3F4nxHzMqYkW; Tue, 8 Dec 2020 04:18:01 +0000 (GMT) Mime-Version: 1.0 Subject: RE: Re: [PATCH v13 0/3] scsi: ufs: Add Host Performance Booster Support Reply-To: daejun7.park@samsung.com Sender: Daejun Park From: Daejun Park To: Greg KH , James Bottomley CC: Christoph Hellwig , Daejun Park , "avri.altman@wdc.com" , "martin.petersen@oracle.com" , "asutoshd@codeaurora.org" , "beanhuo@micron.com" , "stanley.chu@mediatek.com" , "cang@codeaurora.org" , "bvanassche@acm.org" , "tomas.winkler@intel.com" , ALIM AKHTAR , "gregkh@google.com" , "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Sang-yoon Oh , Sung-Jun Park , yongmyung lee , Jinyoung CHOI , Adel Choi , BoRam Shin , SEUNGUK SHIN X-Priority: 3 X-Content-Kind-Code: NORMAL In-Reply-To: X-CPGS-Detection: blocking_info_exchange X-Drm-Type: N,general X-Msg-Generator: Mail X-Msg-Type: PERSONAL X-Reply-Demand: N Message-ID: <1891546521.01607401081656.JavaMail.epsvc@epcpadp4> Date: Tue, 08 Dec 2020 13:12:31 +0900 X-CMS-MailID: 20201208041231epcms2p225d2c155e42f4d45aa86a4ffbd0b2e6e Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: AUTO_CONFIDENTIAL X-CPGSPASS: Y X-CPGSPASS: Y X-Hop-Count: 3 X-CMS-RootMailID: 20201103044021epcms2p8f1556853fc23414442b9e958f20781ce References: <2038148563.21604378702426.JavaMail.epsvc@epcpadp3> <20201207180655.GA30657@infradead.org> <20201207182603.GA2499@infradead.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > On Mon, 2020-12-07 at 19:35 +0100, Greg KH wrote: > > > On Mon, Dec 07, 2020 at 06:26:03PM +0000, Christoph Hellwig wrote: > > > > On Mon, Dec 07, 2020 at 07:23:12PM +0100, Greg KH wrote: > > > > > What "real workload" test can be run on this to help show if it > > > > > is useful or not? These vendors seem to think it helps for some > > > > > reason, otherwise they wouldn't have added it to their silicon :) > > > > > > > > > > Should they run fio? If so, any hints on a config that would be > > > > > good to show any performance increases? > > > > > > > > A real actual workload that matters. Then again that was Martins > > > > request to even justify it. I don't think the broken addressing > > > > that breaks a whole in the SCSI addressing has absolutely not > > > > business being supported in Linux ever. The vendors should have > > > > thought about the design before committing transistors to something > > > > that fundamentally does not make sense. > > > > Actually, that's not the way it works: vendors add commands because > > standards mandate. That's why people who want weird commands go and > > join standard committees. Unfortunately this means that a lot of the > > commands the standard mandates end up not being very useful in > > practice. For instance in SCSI we really only implement a fraction of > > the commands in the standard. > > > > In this case, the industry already tried a very similar approach with > > GEN 1 hybrid drives and it turned into a complete disaster, which is > > why the mode became optional in shingle drives and much better modes, > > which didn't have the huge shared state problem, superseded it. Plus > > truncating the LBA of a READ 16 to 4 bytes is asking for capacity > > problems down the line, so even the actual implementation seems to be > > problematic. > > > > All in all, this looks like a short term fix which will go away when > > the drive capacity improves and thus all the effort changing the driver > > will eventually be wasted. > > "short term" in the embedded world means "this device is stuck with this > chip for the next 8 years", it's not like a storage device you can > replace, so this might be different than the shingle drive mess. Also, > I see many old SoCs still showing up in brand new devices many many > years after they were first introduced, on-chip storage controllers is > something we need to support well if we don't want to see huge > out-of-tree patchsets like UFS traditionally has been lugging around for > many years. > > > > So "time to boot an android system with this enabled and disabled" > > > would be a valid workload, right? I'm guessing that's what the > > > vendors here actually care about, otherwise there is no real stress- > > > test on a UFS system that I know of. > > > > Um, does it? I don't believe even the UFS people have claimed this. > > The problem is that HPB creates a shared state between the driver and > > the device. That shared state has to be populated, which has to happen > > at start of day, so it's entirely unclear if this is a win or a slow > > down for boot. > > Ok, showing that this actually matters is a good rule, Daejun, can you > provide that if you resubmit this patchset? > Sure, I will find out the case which has performance benefit by HPB. Thanks, Daejun