gpu_metrics does not provide 'current_gfxclk', 'current_uclk', 'average_cpu_power' & 'temperature_core' on AMD Ryzen 7000 CPU

[Alex Deucher]

On Mon, Feb 6, 2023 at 5:48 PM sfrcorne <sfrcorne at protonmail.com> wrote:
>
> Dear Alex,
>
> First of all, thank you for your response. Personally, I use a Ryzen 5 7600X however people with a Ryzen 9 7900X are also reporting this issue. The relevant bug report in Mangohud can be found here: "https://github.com/flightlessmango/MangoHud/issues/868".
>
> I looked around a bit in both the Mangohud source code and the Linux kernel source code.
>
> (Mangohud source): From what I understand, Mangohud looks for a file "/sys/class/drm/card*/device/gpu_metrics". If this file exists (and it does exists on my machine), it tries to read this file and extract the relevant GPU data (and in case of an APU also the CPU data) from it (these are the values I was talking about in my previous mail). When the file "/sys/class/drm/card*/device/gpu_metrics" exists, it will not use the data provided by hwmon (/sys/class/hwmon/hwmon*/*).
>
> (Linux kernel): The gpu_metrics file contains different data, depending on what version is used. All valid versions can be found in the source code: "https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/amd/include/kgd_pp_interface.h#L725". For my CPU/APU the 'gpu_metrics_v2_1' structure is used (I tested this by reading the gpu_metrics file myself). Furthermore, I think that for my case, this structure is set by the function "https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_5_ppt.c#L459" but I am not completely sure about this.

The metrics provided by the SMU firmware varies from asic to asic.
For things that are not supported by the metrics table for a
particular asic, those fields would be 0.  You can see what metrics
are supported for your asic in smu_v13_0_5_get_gpu_metrics() as that
function populates the supported fields from the firmware to the
common structure.  current_gfxclk is not supported in your asic, but
average_gfxclk_frequency is.  So you'd want to use whichever field is
available for a particular asic in Mangohud.

>
> Lastly, I am not familiar with umr. I assume that you are referring to "https://gitlab.freedesktop.org/tomstdenis/umr"? If I find some time this weekend, then I will look into this some more.

Yes, that is the right link.  umr uses the same interface as mangohud,
so you should see the same data.

Alex


>
> Kind regards,
> sfrcorne
>
> ------- Original Message -------
> On Monday, February 6th, 2023 at 22:22, Alex Deucher <alexdeucher at gmail.com> wrote:
>
> > On Mon, Feb 6, 2023 at 9:22 AM sfrcorne sfrcorne at protonmail.com wrote:
> >
> > > Hello,
> > >
> > > I hope this is the correct place to ask my question. I was not sure if I should have opened a new issue on Gitlab or send an email here, since I don't know know whether this is a bug or intended behaviour.
> > >
> > > The question is about the new AMD Ryzen 7000 CPU's. These new CPU's have an iGPU and consequently provide a gpu_metrics file for monitoring the GPU/CPU (APU?). This file is used by programs like Mangohud, that try to read (among other values) the following 4 values:
> > > - current_gfxclk
> > > - current_uclk
> > > - average_cpu_power
> > > - temperature_core
> > > However it appears that on AMD Ryzen 7000 CPU's these 4 values are not provided/updated in the gpu_metrics file. Other values like 'average_core_power', 'temperature_l3' and the other 'current_<x>clk' are also not provided/updated but these are not used by Mangohud at the moment.
> > >
> > > Is this intentional or a bug? And will this be fix and/or will support for these 4 values be added in the future?
> >
> >
> > What specific CPU/APU is this? I don't recall off hand how mangohud
> > queries this stuff, but you can take a look at the hwmon interfaces
> > exposed by the driver or if you want the whole metrics table, you can
> > use umr to fetch and decode it via the kernel interface. That will
> > allow you to verify that the firmware is producing the proper data.
> >
> > Alex