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From: Bean Huo <huobean@gmail.com>
To: Avri Altman <Avri.Altman@wdc.com>,
	"daejun7.park@samsung.com" <daejun7.park@samsung.com>,
	"jejb@linux.ibm.com" <jejb@linux.ibm.com>,
	"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
	"asutoshd@codeaurora.org" <asutoshd@codeaurora.org>,
	"stanley.chu@mediatek.com" <stanley.chu@mediatek.com>,
	"cang@codeaurora.org" <cang@codeaurora.org>,
	"bvanassche@acm.org" <bvanassche@acm.org>,
	"tomas.winkler@intel.com" <tomas.winkler@intel.com>,
	ALIM AKHTAR <alim.akhtar@samsung.com>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Sang-yoon Oh <sangyoon.oh@samsung.com>,
	Sung-Jun Park <sungjun07.park@samsung.com>,
	yongmyung lee <ymhungry.lee@samsung.com>,
	Jinyoung CHOI <j-young.choi@samsung.com>,
	Adel Choi <adel.choi@samsung.com>,
	BoRam Shin <boram.shin@samsung.com>
Subject: Re: [RFC PATCH v3 0/5] scsi: ufs: Add Host Performance Booster Support
Date: Mon, 29 Jun 2020 12:53:29 +0200
Message-ID: <94775ad5c35b68d457fdca5a6c89908e227d14af.camel@gmail.com> (raw)
In-Reply-To: <SN6PR04MB464004B3DC7FB046A1E38F43FC6E0@SN6PR04MB4640.namprd04.prod.outlook.com>

Hi Avri

On Mon, 2020-06-29 at 05:24 +0000, Avri Altman wrote:
> Hi Bean,
> > 
> > Hi Daejun
> > 
> > Seems you intentionally ignored to give you comments on my
> > suggestion.
> > let me provide the reason.
> > 
> > Before submitting your next version patch, please check your L2P
> > mapping HPB reqeust submission logical algorithem. I have did
> > performance comparison testing on 4KB, there are about 13%
> > performance
> > drop. Also the hit count is lower. I don't know if this is related
> > to
> > your current work queue scheduling, since you didn't add the timer
> > for
> > each HPB request.
> 
> In device control mode, the various decisions,
> and specifically those that are causing repetitive evictions,
> are made by the device.
> Is this the issue that you are referring to? 
> 

For this device mode, if HPB mapping table of the active region becomes
dirty in the UFS device side, there is repetitive inactive rsp, but it
is not the reason for the condition I mentioned here.  

> As for the driver, do you see any issue that is causing unnecessary
> latency? 
> 

In Daejun's patch, it now uses work_queue, and as long there is new RSP of thesubregion to be activated, the driver will queue "work" to this work
queue, actually, this is deferred work. we don't know when it will be
scheduled/finished. we need to optimize it.


Thanks,
Bean




  reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20200623010201epcms2p11aebdf1fbc719b409968cba997507114@epcms2p1>
2020-06-23  1:02 ` Daejun Park
     [not found]   ` <CGME20200623010201epcms2p11aebdf1fbc719b409968cba997507114@epcms2p5>
2020-06-23  3:50     ` [RFC PATCH v3 1/5] scsi: ufs: Add UFS feature related parameter Daejun Park
     [not found]   ` <CGME20200623010201epcms2p11aebdf1fbc719b409968cba997507114@epcms2p2>
2020-06-23  3:54     ` [RFC PATCH v3 2/5] scsi: ufs: Add UFS-feature layer Daejun Park
     [not found]   ` <CGME20200623010201epcms2p11aebdf1fbc719b409968cba997507114@epcms2p6>
2020-06-23  3:56     ` [RFC PATCH v3 3/5] scsi: ufs: Introduce HPB module Daejun Park
     [not found]   ` <CGME20200623010201epcms2p11aebdf1fbc719b409968cba997507114@epcms2p7>
2020-06-23  4:03     ` [RFC PATCH v3 4/5] scsi: ufs: L2P map management for HPB read Daejun Park
2020-06-24  9:08       ` Avri Altman
     [not found]       ` <CGME20200623010201epcms2p11aebdf1fbc719b409968cba997507114@epcms2p3>
2020-06-25  0:18         ` Daejun Park
2020-06-29  6:15         ` [RFC PATCH v3 0/5] scsi: ufs: Add Host Performance Booster Support Daejun Park
2020-06-29 11:25           ` Bean Huo
2020-06-28 12:26   ` Bean Huo
2020-06-29  5:24     ` Avri Altman
2020-06-29 10:53       ` Bean Huo [this message]
2020-06-29 11:06         ` Avri Altman
2020-06-29 11:39           ` Bean Huo
2020-06-29  5:17   ` Avri Altman
2020-06-23  4:23 ` [RFC PATCH v3 5/5] scsi: ufs: Prepare HPB read for cached sub-region Daejun Park
2020-06-30  1:05 ` [RFC PATCH v3 0/5] scsi: ufs: Add Host Performance Booster Support Daejun Park
2020-06-30  6:39   ` Avri Altman
2020-06-30 21:59     ` Bean Huo
2020-07-01  1:54     ` Alim Akhtar
2020-06-30 22:05   ` Bean Huo
2020-07-01  0:14 ` Daejun Park

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