How to get RMP value of GPU Fans?

[ricciolino]

I notice that psensor package displayed to me the percentage value of the GPU fans along with its associated RPM value.
I am not able to find a way to obtain that value using any command line tool. I am only able to obtain the percentage value of the speed, but I would like to obtain the RPM value that somehow should be retrieved since psensor is able to do that.
I read many post and tried many solutions, but no one of those help me.
I see this post.
I try with this python module.

No way to get RPM values.

OS: Ubuntu 22.04
GPU: Nvidia RTX 3080

Any help ?

_________________
| SOLUTION --> #6 |
-----------------------------

[MAFoElffen]

Uisng the NVidia NVML API library: https://docs.nvidia.com/deploy/nvml-...537982cf647d4e

[ricciolino]

I already tried through it.

But with the API you linked I only get the percentage value.

I also saw the nvmlUnitGetFanSpeedInfo API in this document that should return the RPM value using the structnvmlUnitFanInfo__t structure, anyway it doesn't work for me.

Here is my snippet of code:

#!/usr/bin/python3

import os
import sys
from pynvml import *

nvmlInit()
handle = nvmlDeviceGetHandleByIndex(0)

try:
(info) = nvmlUnitGetFanSpeedInfo(handle)
print(info.speed)
except NVMLError as error:
print(error)

nvmlShutdown()

sys.exit(0)

It raise the "Invalid Argument" exception:

> python3 get_RPM_GPU_fans.py
Invalid Argument

[MAFoElffen]

With pynvml, users where getting errors with that. But others helping them solve those errors reported that if they instead used py3nvml, that the below code worked for them:

import py3nvml
pynvml.nvmlInit()
h = [pynvml.nvmlDeviceGetHandleByIndex(i) for i in range(pynvml.nvmlDeviceGetCount())]
pynvml.nvmlDeviceGetFanSpeedInfo(h[0])

RE: https://docs.nvidia.com/deploy/nvml-...bd6b0ef32ae456

The big reason why you are getting that error is this, from the requirements section of pynvml: https://pythonhosted.org/nvidia-ml-py/

REQUIRES

Python 2.5, or an earlier version with the ctypes module.

Python version 2, not Python3... py3nvml supports Python3... RE: https://morioh.com/p/bbfe67a3d034

I then found a python class written for py3nvml: (starts at line #165)
https://github.com/mark9064/system_m...influx.py#L165

I hope those examples and using the correct modules for Python3 help you...

[ricciolino]

@MAFoElffen I really appreciate your responses trying to give me an help, thank you!
I install py3nvml version for a python3 compatible module, but...

...that the below code worked for them:

import py3nvml
pynvml.nvmlInit()
h = [pynvml.nvmlDeviceGetHandleByIndex(i) for i in range(pynvml.nvmlDeviceGetCount())]
pynvml.nvmlDeviceGetFanSpeedInfo(h[0])

Unfortunately still this code doesn't not work for me.

Executing exactly that snippet, I got this output:

Traceback (most recent call last):
  File "/home/ricciolino/Desktop/tmp/./bla", line 6, in <module>
    pynvml.nvmlInit()
NameError: name 'pynvml' is not defined. Did you mean: 'py3nvml'?

So I rearranged a little bit to make it execute fine (note that nvmlDeviceGetFanSpeedInfo does not exist, do exists either nvmlDeviceGetFanSpeed, that returns the fan speed percentage values, or nvmlUnitGetFanSpeedInfo, that, as per the documentation, should return the RPM value of the fans). Here is the rearranged script.

#!/usr/bin/python3

import os
import sys
from py3nvml import *
py3nvml.nvmlInit()
h = [py3nvml.nvmlDeviceGetHandleByIndex(i) for i in range(py3nvml.nvmlDeviceGetCount())]
print(py3nvml.nvmlUnitGetFanSpeedInfo(h[0]))
py3nvml.nvmlShutdown()
print("CIAO")
sys.exit(0)

but I got:

Traceback (most recent call last):
  File "/home/ricciolino/Desktop/tmp/./bla", line 8, in <module>
    print(py3nvml.nvmlUnitGetFanSpeedInfo(h[0]))
  File "/home/ricciolino/.local/lib/python3.10/site-packages/py3nvml/py3nvml.py", line 1633, in nvmlUnitGetFanSpeedInfo
    _nvmlCheckReturn(ret)
  File "/home/ricciolino/.local/lib/python3.10/site-packages/py3nvml/py3nvml.py", line 719, in _nvmlCheckReturn
    raise NVMLError(ret)
py3nvml.py3nvml.NVMLError_InvalidArgument: Invalid Argument

So still the same Invalid Argument error...

With pynvml, users where getting errors with that. But others helping them solve those errors reported that if they instead used py3nvml, that the below code worked for them:
I then found a python class written for py3nvml: (starts at line #165)

I check it but even in that example the class only use the nvmlDeviceGetFanSpeed API to retrieve the percentage value of the fan speeds. I am not interested in this value. I need the RPM values.

[ricciolino]

I finally found a way to query my GPU for getting RPM fan values.
I made reverse engineering over the psensor source code and I wrote this simple C code snippet to get the RPM value of a specific fan of the GPU (passing 0 or 1 as identifier to the binary).

Here is my get_GPU_fan_RPM_values.c script:

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <X11/Xlib.h>
#include <NVCtrl/NVCtrl.h>
#include <NVCtrl/NVCtrlLib.h>

static Display *display;

static double get_att(int target, int id, int att)
{
    Bool res;
    int temp;

    res = XNVCTRLQueryTargetAttribute(display, target, id, 0, att, &temp);

    if (res == True)
        return temp;

    return -1;
}

void nvidia_cleanup(void)
{
    if (display) {
        XCloseDisplay(display);
        display = NULL;
    }
}

bool isFanId(char number[])
{
    int i = 0;
    if (number[0] == '-')
        return false;
    for (; number[i] != 0; i++)
    {
        if (number[i] > '1' || number[i] < '0')
            return false;
    }
    return true;
}

int main(int argc, char** argv) {

    if ( !(argc == 2) ) return 1;
    if ( !isFanId(argv[1]) ) return 1;

    int fanId = atoi(argv[1]);

    display = XOpenDisplay(NULL);

    if (!display) {
        printf("Cannot open connection to X11 server\n");
        nvidia_cleanup();
        return 1;
    }

    int evt, err;
    if (!XNVCTRLQueryExtension(display, &evt, &err)) {
        printf("XNVCTRLQueryExtension error %d (evt %d)\n", err, evt);
        nvidia_cleanup();
        return 1;
    }

    printf("%d\n", (int)get_att(NV_CTRL_TARGET_TYPE_COOLER, 1, NV_CTRL_THERMAL_COOLER_SPEED));
    //printf("fan %d: %d RPM\n", fanId, (int)get_att(NV_CTRL_TARGET_TYPE_COOLER, 1, NV_CTRL_THERMAL_COOLER_SPEED));

    nvidia_cleanup();
    
    return 0;
}

Compile it with:

gcc -o get_GPU_fan_RPM_values get_GPU_fan_RPM_values.c -lX11 -lXNVCtrl

Execute it like this:

./get_GPU_fan_RPM_values 0

or

./get_GPU_fan_RPM_values 1

[MAFoElffen]

Looks good.

Sorry. Been a very long day, Just got home from work. It's 2 am here.

If solved, please go to the "Thread Tools" link at the upper right of this page, and mark it Solved.

[ricciolino]

Sorry. Been a very long day, Just got home from work. It's 2 am here.

Don't worry at all, in fact thanks for the replies and advice.

If solved, please go to the "Thread Tools" link at the upper right of this page, and mark it Solved.

Will do!