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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 13:39:42 +0200
Message-ID: <c9b71fcb1f072dcf55f3e13da6dd8ccc145d7c74.camel@gmail.com> (raw)
In-Reply-To: <SN6PR04MB46402436A9E1FFE70967C444FC6E0@SN6PR04MB4640.namprd04.prod.outlook.com>

On Mon, 2020-06-29 at 11:06 +0000, Avri Altman wrote:
> > 
> > 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.
> 
> But those "to-do" lists are checked on every completion interrupt and
> on every resume.
> Do you see any scenario in which the "to-be-activated" or "to-be-
> inactivate" work is getting starved?
> 

let me run more testing cases, will back to you if there is new
updates.

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
2020-06-29 11:06         ` Avri Altman
2020-06-29 11:39           ` Bean Huo [this message]
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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