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Service Performance

Pyinstrument is a statistical python profiler which records call stack every 1 ms rather than recording the whole trace. This is done in order to avoid profiling overhead which can increase a lot if some functions are getting called many times and not taking that much time to complete.

This kind of behavior can even distort results by highlighting part of the code/function which might not be slow but getting called many times completing faster. In a way it kind of tries to avoid profiling noise by removing profiling information of faster parts of code.

This kind of behavior also has a drawback that some of the function calls which ran quite fast will not be recorded but they are already fast.

Pyinstrument uses an OS feature called signals to ask OS to send a signal and handle signals using a python signal handler (PyEval_SetProfile) for recording every 1 ms.


import random

def add(a, b):
    return a+b

def get_sum_of_list():
    final_list = []
    for i in range(1000000):
        rand1 = random.randint(1,100)
        rand2 = random.randint(1,100)
        out = add(rand1, rand2)
    return final_list

if __name__ == "__main__":
    l = get_sum_of_list()
  • Below we have profiled script using Pyinstrument without default options. Please make a note that we are using the ! symbol which lets us execute a shell command from Jupyter Notebook. This command can be run exactly the same way from a shell.

!pyinstrument profiling_examples/


  _     ._   __/__   _ _  _  _ _/_   Recorded: 16:39:21  Samples:  2192
 /_//_/// /_\ / //_// / //_'/ //     Duration: 2.199     CPU time: 2.197
/   _/                      v3.2.0

Program: profiling_examples/

2.199 <module>
└─ 2.199 get_sum_of_list
   ├─ 1.714 randint
        [6 frames hidden]  random
           1.442 randrange
           ├─ 0.734 [self]
           └─ 0.708 _randbelow
              ├─ 0.501 [self]
              ├─ 0.153 Random.getrandbits  ../<built-in>:0
              └─ 0.054 int.bit_length  ../<built-in>:0
   ├─ 0.405 [self]
   ├─ 0.050 add
   └─ 0.030 list.append  ../<built-in>:0

To view this report with different options, run:
    pyinstrument --load-prev 2020-11-12T16-39-21 [options]

Reference: pyinstrument-statistical-profiler-for-python-code

AuthX Support

AuthX Support it using a Class called ProfilerMiddleware which is a middleware that can be used to profile the code.

for example:

import os

import uvicorn
from fastapi import FastAPI
from fastapi.responses import JSONResponse

from authx import ProfilerMiddleware

app = FastAPI()

async def profiling():
    return JSONResponse({"Ping Pong": "Hello World!"})

if __name__ == "__main__":
    app_name = os.path.basename(__file__).replace(".py", "")"{app_name}:app", host="", port=8080, workers=1)
  • This class to have 3 functions that expose the profiling information, one is to get the profiling information, one is to get the profiling information in a JSON format and one is to get the profiling information in a HTML format.
app.add_middleware(PyInstrumentProfilerMiddleware, profiler_output_type="html", is_print_each_request=False, html_file_name="profiling.html")