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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,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 06095C433DB for ; Mon, 28 Dec 2020 01:34:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA2F6208BA for ; Mon, 28 Dec 2020 01:34:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726491AbgL1BeJ (ORCPT ); Sun, 27 Dec 2020 20:34:09 -0500 Received: from m43-15.mailgun.net ([69.72.43.15]:63768 "EHLO m43-15.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726361AbgL1BeH (ORCPT ); Sun, 27 Dec 2020 20:34:07 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1609119227; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=eZTjBgbTUfr1OVRJYpoYf8PCujArXTjn/09ZaCNxY/w=; b=TMVI8oTBrgSaQlL50XDabgFO7GHzcWKf/wzfzTqC0ZkxOWYlwPZjTaEkV/FfY6ulHYwncAgf +pHVlBlsDY6tM82g15UKtdmKrUVvhpCFeRR4bdbLWesYLLB5NA/FTtNn8xLDmOoGVmHa+geK psIlcb8oV5cdnBxd6S3U7HTvWUs= X-Mailgun-Sending-Ip: 69.72.43.15 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-east-1.postgun.com with SMTP id 5fe935f97036173f4f932bd7 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 28 Dec 2020 01:33:45 GMT Sender: cang=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id EAD00C433C6; Mon, 28 Dec 2020 01:33:44 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: cang) by smtp.codeaurora.org (Postfix) with ESMTPSA id 434FDC433CA; Mon, 28 Dec 2020 01:33:44 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 28 Dec 2020 09:33:44 +0800 From: Can Guo To: Stanley Chu Cc: Bean Huo , Avri Altman , linux-scsi@vger.kernel.org, martin.petersen@oracle.com, alim.akhtar@samsung.com, jejb@linux.ibm.com, beanhuo@micron.com, asutoshd@codeaurora.org, matthias.bgg@gmail.com, bvanassche@acm.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kuohong.wang@mediatek.com, peter.wang@mediatek.com, chun-hung.wu@mediatek.com, andy.teng@mediatek.com, chaotian.jing@mediatek.com, cc.chou@mediatek.com, jiajie.hao@mediatek.com, alice.chao@mediatek.com Subject: Re: [PATCH v1] scsi: ufs-mediatek: Enable UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL In-Reply-To: <1608817657.14045.30.camel@mtkswgap22> References: <20201222072928.32328-1-stanley.chu@mediatek.com> <1608697172.14045.5.camel@mtkswgap22> <1608796334.14045.21.camel@mtkswgap22> <5eb12622222bd9ba5e705801a204f3160ba3966b.camel@gmail.com> <1608817657.14045.30.camel@mtkswgap22> Message-ID: X-Sender: cang@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-12-24 21:47, Stanley Chu wrote: > Hi Avri, Bean, > > On Thu, 2020-12-24 at 13:01 +0100, Bean Huo wrote: >> On Thu, 2020-12-24 at 11:03 +0000, Avri Altman wrote: >> > > > Do you see any substantial benefit of having >> > > > fWriteBoosterBufferFlushEn >> > > > disabled? >> > > >> > > 1. The definition of fWriteBoosterBufferFlushEn is that host allows >> > > device to do flush in anytime after fWriteBoosterBufferFlushEn is >> > > set as >> > > on. This is not what we want. >> > > >> > > Just Like BKOP, We do not want flush happening beyond host's >> > > expected >> > > timing that device performance may be "randomly" dropped. >> > >> > Explicit flush takes place only when the device is idle: >> > if fWriteBoosterBufferFlushEn is set, the device is idle, and before >> > h8 received. >> > If a request arrives, the flush operation should be halted. >> > So no performance degradation is expected. >> >> Hi Stanley >> >> Avri's comment is correct, fWriteBoosterBufferFlushEn==1, device will >> flush only when it is in idle, once there is new incoming request, the >> flush will be suspended. You should be very careful when you want to >> skip this stetting of this flag. > > Very appreciate your the clarification. > > However similar to "Background Operations Termination Latency", while > the next request comes, device may need some time to suspend on-going > flush operations. This delay may "randomly" degrade the performance > right? That can be case by case (or vendor by vendor), but generally I agree with you on this. > > Since the configuration, i.e., enable > fWriteBoosterBufferFlushDuringHibernate only with > fWriteBoosterBufferFlushEn disabled, has been applied in many of our > mass-produced products these yeas, we would like to keep it unless the > new setting has obvious benefits. Thanks for sharing the info. I will leave the decision to Asutosh on this. Thanks, Can Guo. > > Thanks, > Stanley Chu > >> >> Bean >>