CPU on Fire? Douse the Tab

tabdouse.py

import subprocess
from time import sleep
from datetime import datetime

COL_PID = 0
COL_CPU = 8
COL_NAME = 11

FF_CPU_THRESHOLD = 50
TIME_THRESHOLD = 10

bad_counts = 0
worst_web_components = {}  # pid -> total CPU usage in the time firefox was misbehaving

while True:
    sleep(1)

    sp = subprocess.run('top -b -n1 -o +%CPU'.split(" "), capture_output=True)
    lines = sp.stdout.splitlines()[7:]  # skip the first 7 lines of header

    # first we check total firefox CPU usage
    total_cpu = 0
    for line in lines:
        line = line.decode("utf-8")
        columns = line.split(maxsplit=11)

        ps_name = columns[COL_NAME]
        if 'firefox' not in ps_name and 'Isolate' not in ps_name and 'RDD Pro' not in ps_name:
            continue

        cpu = float(columns[COL_CPU])
        total_cpu += cpu

    if total_cpu > FF_CPU_THRESHOLD:
        bad_counts += 1
    else:
        print(f"{datetime.now().strftime('%H:%M:%S')} Reset at {total_cpu} CPU usage")
        bad_counts = 0

    if bad_counts == 0:
        # no bad firefox processes; we reset the "worst" list and skip the rest
        worst_web_components = {}
        continue

    for line in lines:
        line = line.decode("utf-8")
        columns = line.split(maxsplit=11)

        ps_name = columns[COL_NAME]
        if 'Isolate' not in ps_name and 'RDD Pro' not in ps_name:
            continue

        pid = int(columns[COL_PID])
        cpu = float(columns[COL_CPU])

        if pid not in worst_web_components:
            worst_web_components[pid] = 0
        worst_web_components[pid] += cpu

    if bad_counts >= TIME_THRESHOLD:
        print(f"{datetime.now().strftime('%H:%M:%S')} A FF-related proces was seen {bad_counts} times over the CPU threshold.")

        worst = sorted(worst_web_components.items(), key=lambda x: x[1], reverse=True)[0]
        worst_pid, worst_cpu = worst
        print(f"{datetime.now().strftime('%H:%M:%S')} PID {worst_pid} is worst Isolated Web Component")

        subprocess.run(f"kill {worst_pid}".split(" "))

        # Reset the counters
        bad_counts = 0
        worst_web_components = {}

    else:
        print(f"{datetime.now().strftime('%H:%M:%S')} Firefox was bad {bad_counts} times, but not enough to kill anything.")