lkml.org 
[lkml]   [2020]   [Jun]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRE: [RFC PATCH v3 0/5] scsi: ufs: Add Host Performance Booster Support
    Date


    > -----Original Message-----
    > From: Avri Altman <Avri.Altman@wdc.com>
    > Sent: 30 June 2020 12:09
    > To: daejun7.park@samsung.com; Bean Huo <huobean@gmail.com>;
    > jejb@linux.ibm.com; martin.petersen@oracle.com; asutoshd@codeaurora.org;
    > stanley.chu@mediatek.com; cang@codeaurora.org; bvanassche@acm.org;
    > tomas.winkler@intel.com; ALIM AKHTAR <alim.akhtar@samsung.com>
    > Cc: linux-scsi@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
    >
    > Hi,
    >
    > >
    > > Hi Bean,
    > > > On Mon, 2020-06-29 at 15:15 +0900, Daejun Park wrote:
    > > > > > Seems you intentionally ignored to give you comments on my
    > > > > > suggestion.
    > > > > > let me provide the reason.
    > > > >
    > > > > Sorry! I replied to your comment (
    > > > > https://protect2.fireeye.com/url?k=be575021-e3854728-be56db6e-
    > > 0cc47a31cdf8-
    > >
    > 6c7d0e1e42762b92&q=1&u=https%3A%2F%2Flkml.org%2Flkml%2F2020%2F6%
    > > 2F15%2F1492),
    > > > > but you didn't reply on that. I thought you agreed because you
    > > > > didn't send any more comments.
    > > > >
    > > > >
    > > > > > Before submitting your next version patch, please check your L2P
    > > > > > mapping HPB reqeust submission logical algorithem. I have did
    > > > >
    > > > > We are also reviewing the code that you submitted before.
    > > > > It seems to be a performance improvement as it sends a map request
    > > > > directly.
    > > > >
    > > > > > 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
    > > > >
    > > > > It is interesting that there is actually a performance improvement.
    > > > > Could you share the test environment, please? However, I think
    > > > > stability is important to HPB driver. We have tested our method
    > > > > with the real products and the HPB 1.0 driver is based on that.
    > > >
    > > > I just run fio benchmark tool with --rw=randread, --bs=4kb, --
    > > > size=8G/10G/64G/100G. and see what performance diff with the direct
    > > > submission approach.
    > >
    > > Thanks!
    > >
    > > > > After this patch, your approach can be done as an incremental patch?
    > > > > I would
    > > > > like to test the patch that you submitted and verify it.
    > > > >
    > > > > > your current work queue scheduling, since you didn't add the
    > > > > > timer for each HPB request.
    > > > >
    > > >
    > > > Taking into consideration of the HPB 2.0, can we submit the HPB
    > > > write request to the SCSI layer? if not, it will be a direct submission way.
    > > > why not directly use direct way? or maybe you have a more advisable
    > > > approach to work around this. would you please share with us.
    > > > appreciate.
    > >
    > > I am considering a direct submission way for the next version.
    > > We will implement the write buffer command of HPB 2.0, after patching
    > > HPB 1.0.
    > >
    > > As for the direct submission of HPB releated command including HPB
    > > write buffer, I think we'd better discuss the right approach in depth
    > > before moving on to the next step.
    > I vote to stay with the current implementation because:
    > 1) Bean is probably right about 2.0, but it's out of scope for now -
    > there is a long way to go before we'll need to worry about it
    > 2) For now, we should focus on the functional flows.
    > Performance issues, should such issues indeed exists, can be dealt with later.
    > And,
    > 3) The current code base is running in production for more than 3 years now.
    > I am not so eager to dump a robust, well debugged code unless it absolutely
    > necessary.
    >
    Avri and Bean,
    I think this is good approach to take, and let us add incremental patches to add future specification enhancements.

    > Thanks,
    > Avri
    >


    \
     
     \ /
      Last update: 2020-07-01 03:55    [W:4.689 / U:1.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site