Re: [PATCH v4 0/3] nvme power saving

From: Jens Axboe
Date: Thu Sep 22 2016 - 18:08:56 EST

On 09/22/2016 04:16 PM, Keith Busch wrote:
On Thu, Sep 22, 2016 at 02:33:36PM -0700, J Freyensee wrote:
...and some SSDs don't even support this feature yet, so the number of
different NVMe devices available to test initially will most likely be
small (like the Fultondales I have, all I could check is to see if the
code broke anything if the device did not have this power-save

I agree with Jens, makes a lot of sense to start with this feature

To 'advertise' the feature, maybe make the feature a new selection in
Kconfig? Example, initially make it "EXPERIMENTAL", and later when
more devices implement this feature it can be integrated more tightly
into the NVMe solution and default to on.

Should we just leave the kernel out of this then? I bet we could script
this feature in user space.

That actually might be the sanest approach. Then we can tie it into some
generic PM latency setup in the future, from the kernel, when it's

That way we don't get left with some odd NVMe specific PM sysfs knob
that is exposed to userland.

Jens Axboe