> -----Original Message----- > From: Avri Altman <Avri.Altman@xxxxxxx> > Sent: 30 June 2020 12:09 > To: daejun7.park@xxxxxxxxxxx; Bean Huo <huobean@xxxxxxxxx>; > jejb@xxxxxxxxxxxxx; martin.petersen@xxxxxxxxxx; asutoshd@xxxxxxxxxxxxxx; > stanley.chu@xxxxxxxxxxxx; cang@xxxxxxxxxxxxxx; bvanassche@xxxxxxx; > tomas.winkler@xxxxxxxxx; ALIM AKHTAR <alim.akhtar@xxxxxxxxxxx> > Cc: linux-scsi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Sang-yoon Oh > <sangyoon.oh@xxxxxxxxxxx>; Sung-Jun Park > <sungjun07.park@xxxxxxxxxxx>; yongmyung lee > <ymhungry.lee@xxxxxxxxxxx>; Jinyoung CHOI <j-young.choi@xxxxxxxxxxx>; > Adel Choi <adel.choi@xxxxxxxxxxx>; BoRam Shin > <boram.shin@xxxxxxxxxxx> > 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 >
