NVMe Tuning

[Arwen]

@Redbeard,
Does the new setting survive a reboot?
Does the new setting survive a power cycle?

If it does, then perhaps that drive does not need the saving option.

If it does not save it, you can always add a startup script to make it semi-permanent. (Obviously, on a desktop it's not that critical. I am referring to if you used the same NVMe drive in a Pinebook Pro.)

[Redbeard]

@Redbeard,
Does the new setting survive a reboot?
Does the new setting survive a power cycle?

If it does, then perhaps that drive does not need the saving option.

If it does not save it, you can always add a startup script to make it semi-permanent. (Obviously, on a desktop it's not that critical. I am referring to if you used the same NVMe drive in a Pinebook Pro.)

Unfortunately it doesn't survive a power cycle.   I suspect the smaller capacity versions of the same drive listed in the wiki and discussed in the forum have the same limitation.   If I end up using that drive in the PBP I'll set up a startup script as you suggest.  I've never set one up but I assume I can pretty easily Google how to do so.  It would have to run as root.  Do you know if that is an issue?

[Arwen]

@Redbeard, yes, startup scripts need to run as root, and that's not a problem.
The exact nature of the the startup script varies depending the OS.

[Redbeard]

@Redbeard, yes, startup scripts need to run as root, and that's not a problem.
The exact nature of the the startup script varies depending the OS.

Thanks again.

I just got this working by creating a cron job at boot.  From the terminal, I typed: 

sudo crontab -e

In the editor, I added the following line to the end of the file (just past the last commented line):

@reboot sudo nvme set-feature /dev/nvme0 -f 2 -v 2

I then exited, saving the edit.  After a reboot I ran the following to confirm that it worked:

sudo nvme get-feature /dev/nvme0 -f 2

It came back with:

get-feature:0x2 (Power Management), Current value:0x000002

Which shows that it is working.  I tested this after both a restart and a boot after shutting down entirely, and it worked both ways.  

One thing I did find is that if I used the -s switch in this situation not only does it throw an error that it can't process the save, but the entire command appears not to function.  I originally made the mistake of including the -s switch when I first edited crontab, and when I did that the power state wasn't set after reboot.  So if someone tries this and it comes back with "Current value:00000000" after rebooting, double check that the -s switch isn't included in the crontab line.

[gandlers]

nice work redbeard