Category "multiprocessing"

Occasional deadlock in multiprocessing.Pool

I have N independent tasks that are executed in a multiprocessing.Pool of size os.cpu_count() (8 in my case), with maxtasksperchild=1 (i.e. a fresh worker proce

Python 3.6+: Nested multiprocessing managers cause FileNotFoundError

So I'm trying to use multiprocessing Manager on a dict of dicts, this was my initial try: from multiprocessing import Process, Manager def task(stat): tes

pytorch DataLoader extremely slow first epoch

When I create a PyTorch DataLoader and start iterating -- I get an extremely slow first epoch (x10--x30 slower then all next epochs). Moreover, this problem occ

How to dynamically change self variables, parameters, args... in multiprocessing?

I don't know much of Python yet, but I'm trying to create an app that controls multiple streams of sound simultaneously (It has to do with binaural beats, noise

Real time plotting of serial data with python and tkinter

I have been working for some time to find a way to graph incoming data from an arduino with a Python GUI. I was able to accomplish this using the Matplotlib ani

Why does python multiprocessing script slow down after a while?

I read an old question Why does this python multiprocessing script slow down after a while? and many others before posting this one. They do not answer the prob

Multiprocessing OpenCV in Python

I have a simple Algorithm, I want to run it fast in parallel. The algo is. while stream: img = read_image() pre_process_img = pre_process(img) text

mp.set_start_method('spawn') triggered an error saying the context is already been set

Here is my full code I have succeeded to reproduce the behavior of my main code with a little snippet. In a Google Colab Env, suppose I setup hardware accele

Python - How to use FastAPI and uvicorn.run without blocking the thread?

I'm looking for a possibility to use uvicorn.run() with a FastAPI app but without uvicorn.run() is blocking the thread. I already tried to use processes, subpro

Best way to wait for queue population python multiprocessing

It is first time I play with parallel computing seriously. I am using multiprocessing module in python and I am running into this problem: A queue consumer run

GitHub Actions - parallel self-hosted runners on the same machine

Question related to the topic of Parallelism in Self-Hosted Runners: One self-hosted runner can only run one job at a time, when no available runners are id

Python: How to efficiently open and read a zipfile from multiple processes

I'm trying to open the same .zip file from multiple processes using zipfile and multiprocessing. When I open the .zip file using the with zipfile.ZipFile(self.

python multiprocessing queue implementation

I'm having trouble understanding how to implement queue into a multiprocessing example below. Basically, I want the code to: 1) spawn 2 processes (done) 2) s

Swoole process is hanging forever

I have the simplest Swoole code, which sleeps for a second and prints "Run task" message to the screen. <?php namespace Tests\Util; use PHPUnit\Framework\T

Pool within a Class in Python

I would like to use Pool within a class, but there seems to be a problem. My code is long, I created a small-demo variant to illustrated the problem. It would b

How to apply a function to a 2D numpy array with multiprocessing

Suppose I have the following function: def f(x,y): return x*y How do I apply the funtion to each element in an NxM 2D numpy array using the multiprocessi

How to use multiple CPUs with Python on a HPC?

I'm working on a data analysis project in Python and I'm using a HPC cluster to process my data. I'm having a hard time getting my program to use multiple CPUs

Using multiprocessing pool from celery task raises exception

FOR THOSE READING THIS: I have decided to use RQ instead which doesn't fail when running code that uses the multiprocessing module. I suggest you use that. I a

Multiprocessing : use tqdm to display a progress bar

To make my code more "pythonic" and faster, I use "multiprocessing" and a map function to send it a) the function and b) the range of iterations. The implanted

Does user level threads take advantage of multiprocessing?

Does user level threads take advantage of multiprocessing ? I read one such answer here. But, it's not clear though. What does it mean by "user threads cannot