/proc/stat

#!/usr/bin/env python3

import re
import time
from statistics import mean
from collections import namedtuple, defaultdict
from pathlib import Path



CPU_REGEX = re.compile("cpu(\d+)")
CPU_STAT = Path("/proc/stat")
STAT = namedtuple("stat", "cpu user nice system idle iowait irq softirq steal guest guest_nice")
TOTAL_LAST = 0
BUSY_LAST = 0


def read_ticks():
    results = []
    stats = CPU_STAT.read_text()
    for line in stats.splitlines():
        match = CPU_REGEX.search(line)
        if match:
            cpu, *values = line.split()
            result = STAT(cpu, *map(int, values))
            busy_ticks = sum((result.user, result.nice, result.system, result.irq, result.softirq))
            total_ticks = sum((busy_ticks, result.idle, result.iowait))
            results.append((cpu, busy_ticks, total_ticks))
    return results


def get_rel_load(interval=1):
    cpu, busy, total = zip(*read_ticks())
    last_busy = {cpu: busy for cpu, busy in zip(cpu, busy)}
    last_ticks = {cpu: total for cpu, total in zip(cpu, total)}
    result = []
    time.sleep(interval)
    for cpu, busy_ticks, total_ticks in read_ticks():
        result.append((
            cpu,
            (busy_ticks - last_busy[cpu]) / (total_ticks - last_ticks[cpu]) * 100,
        ))
        last_busy[cpu] = busy_ticks
        last_ticks[cpu] = total_ticks
    return result



if __name__ == "__main__":
    #for results in get_rel_load():
    #    print("\x1b[2J\x1b[H", end="")
    #    for cpu, load in results:
    #        print(f"[{cpu:<5}] {load:.1f} %")
    load = [load for cpu, load in get_rel_load()]
    print(mean(load))