How to monitor usage of CPU when function is called in Python psutil?
Question:
Hey I’m learning psutil package and I want to know how to display current CPU usage when function is in progress? I suppose I need some threading or something like this, but how to do it? Thank u for any answers.
import psutil
import random
def iHateThis():
tab = []
for i in range(100000):
tab.append(random.randint(1, 10000))
tab.sort()
return tab;
while(True):
currentProcess = psutil.Process()
print(currentProcess.cpu_percent(interval=1))
Answers:
You can do this with the multiprocessing library. multiprocessing.Process is a class that represents a threaded process, is initiated with a function and name, and can be run at any time with .start().
import multiprocessing
import psutil
import random
def iHateThis():
tab = []
for i in range(100000):
tab.append(random.randint(1, 10000))
tab.sort()
return tab;
hate = multiprocessing.Process(name='hate', target=iHateThis)
hate.start()
while(True):
currentProcess = psutil.Process()
print(currentProcess.cpu_percent(interval=1))
You can use threading to run iHateThis or to run function with cpu_percent(). I choose second version. I will run cpu_percent() in thread.
Because it uses while True so thread would run forever and there wouldn’t be nice method to stop thread so I use global variaable running with while running to have method to stop this loop.
import threading
import psutil
def display_cpu():
global running
running = True
currentProcess = psutil.Process()
# start loop
while running:
print(currentProcess.cpu_percent(interval=1))
def start():
global t
# create thread and start it
t = threading.Thread(target=display_cpu)
t.start()
def stop():
global running
global t
# use `running` to stop loop in thread so thread will end
running = False
# wait for thread's end
t.join()
and now I can use it to start and stop thread which will display CPU. Because I may have to stop process using Ctrl+C so it will raise error so I use try/finally to stop thread even if there will be error.
def i_hate_this():
tab = []
for i in range(1000000):
tab.append(random.randint(1, 10000))
tab.sort()
return tab
# ---
start()
try:
result = i_hate_this()
finally: # stop thread even if I press Ctrl+C
stop()
Full code:
import random
import threading
import psutil
def display_cpu():
global running
running = True
currentProcess = psutil.Process()
# start loop
while running:
print(currentProcess.cpu_percent(interval=1))
def start():
global t
# create thread and start it
t = threading.Thread(target=display_cpu)
t.start()
def stop():
global running
global t
# use `running` to stop loop in thread so thread will end
running = False
# wait for thread's end
t.join()
# ---
def i_hate_this():
tab = []
for i in range(1000000):
tab.append(random.randint(1, 10000))
tab.sort()
return tab
# ---
start()
try:
result = i_hate_this()
finally: # stop thread even if I press Ctrl+C
stop()
BTW: this can be converted to class which inherits from class Thread and then it can hide variable running in class.
import psutil
import random
import threading
class DisplayCPU(threading.Thread):
def run(self):
self.running = True
currentProcess = psutil.Process()
while self.running:
print(currentProcess.cpu_percent(interval=1))
def stop(self):
self.running = False
# ----
def i_hate_this():
tab = []
for i in range(1000000):
tab.append(random.randint(1, 10000))
tab.sort()
return tab
# ---
display_cpu = DisplayCPU()
display_cpu.start()
try:
result = i_hate_this()
finally: # stop thread even when I press Ctrl+C
display_cpu.stop()
It could be also converted to context manager to run it as
with display_cpu():
i_hate_this()
but I skip this part.
I don’t think you need to use psutil Process class as I think it is intended to be used to monitor a specific process. Using the code snippet from @furas (the accepted answer), you can do it with a thread like this:
def run(self):
self.run = True
while self.run:
psutil.cpu_percent(interval=1)
it works the same as the accepted answer in the following case:
_monitor.start()
try:
for i in range(50):
time.sleep(0.2)
finally:
_monitor.stop()
If you don’t want to code it, I am doing it in a public repo if it can be of any help for someone: https://github.com/GTimothee/monitor
Let approach the problem differently and propose a decorator that can serve to measure CPU utilization while running
from functools import partial, wraps
def log_cpu_usage(func=None, msg_prefix: str = None):
"""
This function is a decorator that measures the execution time of a function and logs it.
"""
debug = True
if not debug:
return func
if func is None:
return partial(log_cpu_usage, msg_prefix=msg_prefix)
def new_func(data: mp.Queue, *args, **kwargs):
result = func(*args, **kwargs)
data.put(result)
@wraps(func)
def trace_execution(*args, **kwargs):
manager = mp.Queue() # to save return val between multi process
worker_process = mp.Process(target=new_func, args=(manager, *args), kwargs=kwargs)
worker_process.start()
p = psutil.Process(worker_process.pid)
cpu_percents = []
while worker_process.is_alive(): # while the subprocess is running
cpu_percents.append(p.cpu_percent() / psutil.cpu_count())
time.sleep(0.01)
worker_process.join()
ret_values = manager.get()
return sum(cpu_percents) / len(cpu_percents), ret_values
@log_cpu_usage
def iHateThis():
pass
Hey I’m learning psutil package and I want to know how to display current CPU usage when function is in progress? I suppose I need some threading or something like this, but how to do it? Thank u for any answers.
import psutil
import random
def iHateThis():
tab = []
for i in range(100000):
tab.append(random.randint(1, 10000))
tab.sort()
return tab;
while(True):
currentProcess = psutil.Process()
print(currentProcess.cpu_percent(interval=1))
You can do this with the multiprocessing library. multiprocessing.Process is a class that represents a threaded process, is initiated with a function and name, and can be run at any time with .start().
import multiprocessing
import psutil
import random
def iHateThis():
tab = []
for i in range(100000):
tab.append(random.randint(1, 10000))
tab.sort()
return tab;
hate = multiprocessing.Process(name='hate', target=iHateThis)
hate.start()
while(True):
currentProcess = psutil.Process()
print(currentProcess.cpu_percent(interval=1))
You can use threading to run iHateThis or to run function with cpu_percent(). I choose second version. I will run cpu_percent() in thread.
Because it uses while True so thread would run forever and there wouldn’t be nice method to stop thread so I use global variaable running with while running to have method to stop this loop.
import threading
import psutil
def display_cpu():
global running
running = True
currentProcess = psutil.Process()
# start loop
while running:
print(currentProcess.cpu_percent(interval=1))
def start():
global t
# create thread and start it
t = threading.Thread(target=display_cpu)
t.start()
def stop():
global running
global t
# use `running` to stop loop in thread so thread will end
running = False
# wait for thread's end
t.join()
and now I can use it to start and stop thread which will display CPU. Because I may have to stop process using Ctrl+C so it will raise error so I use try/finally to stop thread even if there will be error.
def i_hate_this():
tab = []
for i in range(1000000):
tab.append(random.randint(1, 10000))
tab.sort()
return tab
# ---
start()
try:
result = i_hate_this()
finally: # stop thread even if I press Ctrl+C
stop()
Full code:
import random
import threading
import psutil
def display_cpu():
global running
running = True
currentProcess = psutil.Process()
# start loop
while running:
print(currentProcess.cpu_percent(interval=1))
def start():
global t
# create thread and start it
t = threading.Thread(target=display_cpu)
t.start()
def stop():
global running
global t
# use `running` to stop loop in thread so thread will end
running = False
# wait for thread's end
t.join()
# ---
def i_hate_this():
tab = []
for i in range(1000000):
tab.append(random.randint(1, 10000))
tab.sort()
return tab
# ---
start()
try:
result = i_hate_this()
finally: # stop thread even if I press Ctrl+C
stop()
BTW: this can be converted to class which inherits from class Thread and then it can hide variable running in class.
import psutil
import random
import threading
class DisplayCPU(threading.Thread):
def run(self):
self.running = True
currentProcess = psutil.Process()
while self.running:
print(currentProcess.cpu_percent(interval=1))
def stop(self):
self.running = False
# ----
def i_hate_this():
tab = []
for i in range(1000000):
tab.append(random.randint(1, 10000))
tab.sort()
return tab
# ---
display_cpu = DisplayCPU()
display_cpu.start()
try:
result = i_hate_this()
finally: # stop thread even when I press Ctrl+C
display_cpu.stop()
It could be also converted to context manager to run it as
with display_cpu():
i_hate_this()
but I skip this part.
I don’t think you need to use psutil Process class as I think it is intended to be used to monitor a specific process. Using the code snippet from @furas (the accepted answer), you can do it with a thread like this:
def run(self):
self.run = True
while self.run:
psutil.cpu_percent(interval=1)
it works the same as the accepted answer in the following case:
_monitor.start()
try:
for i in range(50):
time.sleep(0.2)
finally:
_monitor.stop()
If you don’t want to code it, I am doing it in a public repo if it can be of any help for someone: https://github.com/GTimothee/monitor
Let approach the problem differently and propose a decorator that can serve to measure CPU utilization while running
from functools import partial, wraps
def log_cpu_usage(func=None, msg_prefix: str = None):
"""
This function is a decorator that measures the execution time of a function and logs it.
"""
debug = True
if not debug:
return func
if func is None:
return partial(log_cpu_usage, msg_prefix=msg_prefix)
def new_func(data: mp.Queue, *args, **kwargs):
result = func(*args, **kwargs)
data.put(result)
@wraps(func)
def trace_execution(*args, **kwargs):
manager = mp.Queue() # to save return val between multi process
worker_process = mp.Process(target=new_func, args=(manager, *args), kwargs=kwargs)
worker_process.start()
p = psutil.Process(worker_process.pid)
cpu_percents = []
while worker_process.is_alive(): # while the subprocess is running
cpu_percents.append(p.cpu_percent() / psutil.cpu_count())
time.sleep(0.01)
worker_process.join()
ret_values = manager.get()
return sum(cpu_percents) / len(cpu_percents), ret_values
@log_cpu_usage
def iHateThis():
pass