Automatic temperature-based fan-speed control for AMD GPUs in Linux

amdfan.py

from bisect import bisect_left
from subprocess import Popen, PIPE
from time import sleep
import numpy as np

def get_temperature(gpu=0):
    lines = Popen(["aticonfig", "--adapter=%d" % gpu, "--od-gettemperature"],
                  stdout=PIPE).communicate()[0].split("\n")
    lines = [xx.strip() for xx in lines if len(xx.strip()) > 0]
    # Adapter 0 - AMD Radeon HD 6800 Series 
    #        Sensor 0: Temperature - 63.00 C
    #
    templine = lines[1].strip()
    fields = templine.split()
    assert(fields[2] == "Temperature")
    return float(fields[4])

def set_fan_speed(fanspeed_pct, gpu=0):
    output = Popen(["aticonfig", "--pplib-cmd",
                    "set fanspeed %d %d" % (gpu, fanspeed_pct)],
                   stdout=PIPE).communicate()[0]
    assert(output.strip() == "PPLIB command execution is Successful!")
    return

def get_fan_speed(gpu=0):
    lines = Popen(["aticonfig", "--pplib-cmd", "get fanspeed %d" % gpu],
                   stdout=PIPE).communicate()[0].split("\n")
    # Fan speed query: 
    # Query Index: 0, Speed in percent
    # Result: Fan Speed: 20%

    linefields = [xx.strip().split() for xx in lines if len(xx.strip()) > 0]
    assert(" ".join(linefields[-1][1:3]) == "Fan Speed:")
    # Strip the %
    return int(linefields[-1][-1][:-1])

class LinearInterpolatingFanCurve:
    def __init__(self, curve):
        curve.sort()
        assert(curve[0][1] >= 20)
        assert(curve[-1][1] == 100)
        self.temps, self.fans = zip(*curve)
        self.temps = map(float, self.temps)
        self.fans = map(float, self.fans)
    def temp2fan(self, temp):
        if temp < self.temps[0]:
            return self.fans[0]
        elif temp > self.temps[-1]:
            return self.fans[-1]
        else:
            idx = bisect_left(self.temps, temp)
            tleft = self.temps[idx-1]
            tright = self.temps[idx]
            fleft = self.fans[idx-1]
            fright = self.fans[idx]
            fanspeed = (temp-tleft)/(tright-tleft)  * fright +\
                       (tright-temp)/(tright-tleft) * fleft
            fanspeed = int(round(fanspeed))
            print "Tl =",tleft,"Tr =",tright,"Fl =",fleft,"Fr =",fright,"T =",temp,"Fs =",fanspeed
            return fanspeed

def main():
    print "Manual fan speed control is dangerous and can fry your hardware!"
    print "Use this program at your own risk! I take no responsibility!"

    poll_period = 1 
    buffer_size = 4
    hysteresis = 1
    # Temperature curve has control points specified by pairs of
    # (temperature in degC, fan speed in %)
    curve = [( 0, 20), (65, 20),
             (70, 40),
             (80, 70), (90, 100)]

    fanmap = LinearInterpolatingFanCurve(curve)
    fanspeed = get_fan_speed()
    fantemp = get_temperature()
    temps_buffer = np.empty((buffer_size,))
    temps_buffer[:] = fantemp
    idx = 0
    while True:
        temps_buffer[idx] = get_temperature()
        idx = (idx + 1) % buffer_size
        temp = np.mean(temps_buffer)
        fan = fanmap.temp2fan(temp)
        if fan != fanspeed and abs(temp-fantemp) > hysteresis:
            set_fan_speed(fan)
            fanspeed = fan
            fantemp = temp
            print "\tSet fan speed to",get_fan_speed()
        sleep(poll_period)

if __name__ == "__main__":
    main()