int | float, lavgs: dict[int, LoadEntry]): """Initialize load averages based on linear interpolation of system load averages and instant load count.""" sys = getloadavg() slopes = ((sys[0] - now) / 60, (sys[1] - sys[0]) / 240, (sys[2] - sys[1]) / 600) for period in [10, 30, 60, 120, 300, 900, 1800, 3600]: exp_factor = exp(-REFRESH_RATE / period) if period < 60: est_avg = now + slopes[0] * (period - 60) elif period < 300: est_avg = sys[0] + slopes[1] * (period - 300) else: est_avg = sys[1] + slopes[2] * (period - 900) lavgs[period] = LoadEntry(avg=max(est_avg, 0), exp=exp_factor)

def update_loads(lavgs: dict[int, LoadEntry], current_load: int | float) -> None: for _, entry in lavgs.items(): entry.avg = entry.avg * entry.exp + current_load * (1 - entry.exp)

if os.name == "posix": uname = os.uname()[0].lower() getloadavg = os.getloadavg

if uname == "linux": def get_current_load() -> int: load = 0 with open("/proc/stat", "r") as f: for line in f: if line.startswith("procs_running "): load += int(line.split()[1]) # Read procs_running load -= 1 # Subtract one for ourself elif line.startswith("procs_blocked ") and COUNT_DISKWAIT: load += int(line.split()[1]) # Read procs_blocked return load

else: PS_THREAD_OPTION = "-H" if os.uname()[0].lower().endswith("bsd") else "-M" PS_DISK_WAIT = "U" if os.uname()[0] == "Darwin" else "D" PS_STATES = ("R" + PS_DISK_WAIT) if COUNT_DISKWAIT else "R"

def get_current_load() -> int: with os.popen(f"ps {PS_THREAD_OPTION}ax -o stat", "r") as f: states = map(f, lambda line: line.split()[-1]) # Get the last column. Required on macOS! return sum(1 if state[0] in PS_STATES else 0 for state in states) - 1

elif os.name == "nt": # It is possible to use Windows performance counters to get a queue length. # In fact, Microsoft recommends it as an additional metric for load in addition to CPU usage: # https://learn.microsoft.com/en-us/biztalk/technical-guides/using-the-performance-analysis-of-logs-pal-tool#processor-queue-length-analysis # Using it we can also obtain a load similar to Unix systems. from pyperfmon import pyperfmon

pm = pyperfmon.pyperfmon() ncores = os.cpu_count() get_counter = lambda x: pm.getCounter(x)

def get_current_load() -> float: return ( # Threads waiting for CPU, not running ones get_counter(r"System\Processor Queue Length") # Approximate number of threads using CPU + get_counter(r"Processor\_Total\% Processor Time") * ncores # Threads waiting for disk I/O + get_counter(r"PhysicalDisk\_Total\Current Disk Queue Length") if COUNT_DISKWAIT else 0 )

def getloadavg() -> tuple[float, float, float]: # Dummy implementation for Windows load = get_current_load() return (load, load, load)

def main(): lavgs: dict[int, LoadEntry] = {} current_load = get_current_load() initialize_loads(current_load, lavgs) heading = ["SYSTIME", " CURR"] + [str(x) for x in PERIODS] print("\t".join(heading)) while True: # Always print before recalculating entries = [f"{datetime.now().strftime('%H:%M:%S')} {current_load:.4f}"] entries += [f"{entry.avg:.4f}" for entry in lavgs.values()] print("\t".join(entries), flush=True)

# Sleep and wait. This assumes that the time used to update a new line is # minuscule compared to the time slept. If this is not the case, a # sleepuntil()-type reckoning should be used. time.sleep(REFRESH_RATE)

# Print current_load = get_current_load() update_loads(lavgs, current_load)

if __name__ == "__main__": main()

Other system performance commands

Other commands for assessing system performance include:

* uptime the system reliability and load average
* top for an overall system view
** htop interactive process viewer
* btop another overall system view tool
* vmstat vmstat reports information about runnable or blocked processes, memory, paging, block I/O, traps, and CPU.
* dool (formerly dstat), atop helps correlate all existing resource data for processes, memory, paging, block I/O, traps, and CPU activity.
* iftop interactive network traffic viewer per interface
* nethogs interactive network traffic viewer per process
* iotop interactive I/O viewer
* iostat for storage I/O statistics
* netstat for network statistics
* mpstat for CPU statistics
* tload load average graph for terminal
* xload load average graph for X