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Message-ID: <304cb44c67dc1d5fe081ea4450823c1c3b456284.camel@gmail.com>
Subject: Re: [PATCH v2 0/9] Add Host control mode to HPB
From:   Bean Huo <huobean@gmail.com>
To:     Avri Altman <avri.altman@wdc.com>,
        "James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     gregkh@linuxfoundation.org, Bart Van Assche <bvanassche@acm.org>,
        yongmyung lee <ymhungry.lee@samsung.com>,
        Daejun Park <daejun7.park@samsung.com>,
        alim.akhtar@samsung.com, asutoshd@codeaurora.org,
        Zang Leigang <zangleigang@hisilicon.com>,
        Avi Shchislowski <avi.shchislowski@wdc.com>,
        Bean Huo <beanhuo@micron.com>, cang@codeaurora.org,
        stanley.chu@mediatek.com
Date:   Fri, 05 Feb 2021 12:43:23 +0100
In-Reply-To: <ec32248a3e56eef83744cd4844210d347add27d3.camel@gmail.com>
References: <20210202083007.104050-1-avri.altman@wdc.com>
         <ec32248a3e56eef83744cd4844210d347add27d3.camel@gmail.com>
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On Fri, 2021-02-05 at 12:36 +0100, Bean Huo wrote:
> > to whatever recommendation received from the device - In host
> > control
> > mode, the host uses its own algorithms to decide which regions
> > should
> > be activated or inactivated.
> > 
> > We kept the host managed heuristic simple and concise.
> > 
> > Aside from adding a by-spec functionality, host control mode
> > entails
> > some further potential benefits: makes the hpb logic transparent
> > and
> > readable, while allow tuning / scaling its various parameters, and
> > utilize system-wide info to optimize HPB potential.
> 
> Hi Avri
> In addition to the above advantage of HPB device mode, would you
> please
> share the performance comparison data with host mode? that will draw
> more attention, since you mentioned "you tested on Galaxy S20, and
> Xiaomi Mi10 pro", I think you have this kind of data.
> 
> Your HPB host driver sits in the ufs driver. Since my HPB host mode
> driver is also implemented in the UFS driver layer, I did test my HPB
> driver between device mode and host mode. Saw there is an
> improvement,
> but not significant. If you can share your HPB drviver data, that
> will
> be awesome.
> 
> Kind regards,
> Bean

So sorry, there are several typos, easily confused you. correct them as
below:

Hi Avri

In addition to the above advantage of HPB "host control mode", would
you please share the performance comparison data with "device control
mode"? that will draw more attention, since you mentioned "you tested
on Galaxy S20, and Xiaomi Mi10 pro", I think you have this kind of
data.

Your HPB "host control mode" driver sits in the ufs driver. Since my
HPB "host control mode" driver is also implemented in the UFS driver
layer, I did test my HPB driver between device mode and host mode. Saw
UFS HPB "host control mode" driver has performance gain comparing to
HPB "device control mode" driver, but not significant. If you can share
your HPB host control mode drviver data, that will be awesome.

Kind regards,
Bean