RE: [PATCH v2 0/9] Add Host control mode to HPB

[Avri Altman]

Hi Bean,
 
> 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.
Host control mode wasn't standardized to overcome device mode performance.
Instead, host control mode, entails several advantages comparing to device control mode:
- Allow OEM vendors to have a unified HPB approach, with minor to null performance volatility across different storage vendors
- Flexible and transparent logic which doesn’t requires device firmware changes.
Hence, the discussion of host-control vs device control performance gain is chasing the red herring.

Thanks,
Avri