No reduced power consumption?

[eskimor]

Hi there!

Thank you very much for your awesome work! I am not on Arch so I simply applied the patches to my distros kernel 4.9.9, like it is done in your PKGBUILD file. Is this enough for it to work?

I am asking because I had a higher power consumption after applying the patches. It went up from 3.9 Watts to 4.7 and higher. (Measured with powertop.) Laptop is xps13, 2016 - same as yours but with i5 CPU.

[damige]

It should work if you apply the APST.patch, pm_qos1.patch, pm_qos2.patch, pm_qos3.patch, nvme.patch patches to a 4.9.x kernel.
If you get output "enabled" when doing: "nvme get-feature -f 0x0c -H /dev/nvme0" it should be working.
Keep in mind though that to see the benefit the ssd needs to be idle.

Testing power usage consistently is quite a challenge. Keep an eye on it over time, it would be very strange if this patch would actually cause higher power usage compared to the same unpatched kernel.

[eskimor]

Thank you! I'll check it out!

[eskimor]

Well ok nvme get-feature says enabled, but I could swear power consumption is higher - watching for 16 minutes now. At the very least it did not get better. I have nothing open but power top and now a web browser. Weird.

[damige]

I'm assuming that if you reboot into your vanilla kernel its back to lower consumption again? If so, maybe the vanilla kernel is setting some other kernel settings than you are setting? A lot of this can depend on your distro of choice.

[eskimor]

yep. Fortunately I can switch easily, as I am using nixos. I am also not changing anything but applying the patches or not. I am using exactly the same config otherwise.

[damige]

I'm not sure what i can do to help, the behavior you describe i have not seen or heard of before. Especially since you use almost the same hardware.

[eskimor]

No problem - thank you! power consumption is pretty good already, so it is not a big problem. Just thought I'll post it here, in case someone else experiences something similar. For the record I am using a 4.9.9 kernel on nixos.

[damige]

One thing just came to mind. check your APST.patch, make sure you have the one that does not disable the SM951 from using APST.
wrong one: https://github.com/damige/linux-nvme/blob/master/patches/APST-FULL/APST-FULL.patch
right one: https://github.com/damige/linux-nvme/blob/master/patches/4.9.x/APST.patch

[eskimor]

Does this look right? I could try that:

        kernelPatches = pkgs.linux_4_9.kernelPatches ++ [
          { patch=./linux-nvme/patches/4.9.x/APST.patch ; name = "nvme-apst";}
          { patch=./linux-nvme/patches/4.9.x/pm_qos1.patch ; name = "nvme-qos1";}
          { patch=./linux-nvme/patches/4.9.x/pm_qos2.patch ; name = "nvme-qos2";}
          { patch=./linux-nvme/patches/4.9.x/pm_qos3.patch ; name = "nvme-qos3";}
          { patch=./linux-nvme/patches/4.9.x/nvme.patch ; name = "nvme";}

I actually used until now (did not see the patches directory):

        kernelPatches = pkgs.linux_4_9.kernelPatches ++ [
          { patch=./linux-nvme/src/4.9.9/APST.patch ; name = "nvme-apst";}
          { patch=./linux-nvme/src/4.9.9/pm_qos1.patch ; name = "nvme-qos1";}
          { patch=./linux-nvme/src/4.9.9/pm_qos2.patch ; name = "nvme-qos2";}
          { patch=./linux-nvme/src/4.9.9/pm_qos3.patch ; name = "nvme-qos3";}
          { patch=./linux-nvme/src/4.9.9/nvme.patch ; name = "nvme";}
        ];

I guess this should be the same?

[damige]

I made the patches directory an hour ago, to make it more clear for people wanting to patch other distros.
The patches you list should be exactly the same ones

[eskimor]

Uh ok - good to know that I am not that blind. :-)

[damige]

Probably a stupid question: Are you using the same kernel parameters, stock vs nvme?

[eskimor]

:-) absolutely! The patches are really the only difference. I can be so sure, because of the declarative setup of nix. I changed nothing else.