Re: [PATCH] scsi: switch to scsi-mq by default

[Ming Lei]

On Wed, Jul 11, 2018 at 4:31 PM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> On 11/07/18 05:52, Martin K. Petersen wrote:
>>
>> Johannes,
>>
>>> It has been more than one year since we tried to change the default
>>> from legacy to multi queue in SCSI with commit c279bd9e406 ("scsi:
>>> default to scsi-mq"). But due to issues with suspend/resume and
>>> performance problems it had been reverted again with commit
>>> cbe7dfa26eee ("Revert "scsi: default to scsi-mq"").
>>>
>>> In the meantime there have been a substantial amount of performance
>>> improvements and suspend/resume got fixed as well, thus we can
>>> re-enable scsi-mq without a significant performance penalty.
>>
>> Applied to 4.19/scsi-queue, thanks!
>>
>
> But there is no runtime pm support, is there?  I tried enabling runtime PM
> for UFS SCSI devices with scsi-mq and it didn't work, which is a regression.

I just posted one RFC patchset for supporting runtime PM on scsi_mq, and
looks it works in my test on usb-storage.

https://marc.info/?l=linux-block&m=153132657922233&w=2

thanks,
Ming Lei