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Thu, 24 Dec 2020 05:47:45 -0800 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs02n2.mediatek.inc (172.21.101.101) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 24 Dec 2020 21:47:35 +0800 Received: from [172.21.77.33] (172.21.77.33) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 24 Dec 2020 21:47:35 +0800 Message-ID: <1608817657.14045.30.camel@mtkswgap22> Subject: Re: [PATCH v1] scsi: ufs-mediatek: Enable UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL From: Stanley Chu To: Bean Huo Date: Thu, 24 Dec 2020 21:47:37 +0800 In-Reply-To: <5eb12622222bd9ba5e705801a204f3160ba3966b.camel@gmail.com> References: <20201222072928.32328-1-stanley.chu@mediatek.com> <1608697172.14045.5.camel@mtkswgap22> <1608796334.14045.21.camel@mtkswgap22> <5eb12622222bd9ba5e705801a204f3160ba3966b.camel@gmail.com> X-Mailer: Evolution 3.2.3-0ubuntu6 MIME-Version: 1.0 X-TM-SNTS-SMTP: E5D6A4B292CE8157DB5E053A6579C29FC5F9632B357D9219E59E6662DB493D8A2000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201224_085757_761843_4094E178 X-CRM114-Status: GOOD ( 20.68 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "jiajie.hao@mediatek.com" , "alice.chao@mediatek.com" , "linux-scsi@vger.kernel.org" , "martin.petersen@oracle.com" , "andy.teng@mediatek.com" , "jejb@linux.ibm.com" , "chun-hung.wu@mediatek.com" , "kuohong.wang@mediatek.com" , "linux-kernel@vger.kernel.org" , "cc.chou@mediatek.com" , Avri Altman , Can Guo , "linux-mediatek@lists.infradead.org" , "peter.wang@mediatek.com" , "alim.akhtar@samsung.com" , "matthias.bgg@gmail.com" , "asutoshd@codeaurora.org" , "chaotian.jing@mediatek.com" , "bvanassche@acm.org" , "linux-arm-kernel@lists.infradead.org" , "beanhuo@micron.com" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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? 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, Stanley Chu > > Bean > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel