multithreading – Make Me Engineer

FastAPI python: How to run a thread in the background?

June 25, 2023 by Tarik

Option 1 You should start your Thread before calling uvicorn.run, as uvicorn.run is blocking the thread. import time import threading from fastapi import FastAPI import uvicorn app = FastAPI() class BackgroundTasks(threading.Thread): def run(self,*args,**kwargs): while True: print(‘Hello’) time.sleep(5) if __name__ == ‘__main__’: t = BackgroundTasks() t.start() uvicorn.run(app, host=”0.0.0.0″, port=8000) You could also start your thread using … Read more

How do I use threading in Python?

June 15, 2023 by Tarik

Since this question was asked in 2010, there has been real simplification in how to do simple multithreading with Python with map and pool. The code below comes from an article/blog post that you should definitely check out (no affiliation) – Parallelism in one line: A Better Model for Day to Day Threading Tasks. I’ll … Read more

Do two synchronized methods execute simultaneously

June 15, 2023 by Tarik

If t1 access the m1 method (synchronized method), could t2 thread access m2 method (synchronized method) simultaneously? The synchronized keyword applies on object level, and only one thread can hold the lock of the object. So as long as you’re talking about the same object, then no, t2 will wait for t1 to release the … Read more

Does an asynchronous call always create/call a new thread?

June 15, 2023 by Tarik

This is an interesting question. Asynchronous programming is a paradigm of programming that is principally single threaded, i.e. “following one thread of continuous execution”. You refer to javascript, so lets discuss that language, in the environment of a web browser. A web browser runs a single thread of javascript execution in each window, it handles … Read more

How does the JVM terminate daemon threads? or How to write daemon threads that terminate gracefully

June 15, 2023 by Tarik

I just wrote the following code as a test: public class DaemonThreadPlay { public static void main(String [] args) { Thread daemonThread = new Thread() { public void run() { while (true) { try { System.out.println(“Try block executed”); Thread.sleep(1000l); } catch (Throwable t) { t.printStackTrace(); } } } @Override public void finalize() { System.out.println(“Finalize method … Read more

WPF BackgroundWorker vs. Dispatcher

June 15, 2023 by Tarik

The main difference between the Dispatcher and other threading methods is that the Dispatcher is not actually multi-threaded. The Dispatcher governs the controls, which need a single thread to function properly; the BeginInvoke method of the Dispatcher queues events for later execution (depending on priority etc.), but still on the same thread. BackgroundWorker on the … Read more

Is it possible to force an existing Java application to use no more than x cores?

June 15, 2023 by Tarik

It’s called setting CPU affinity, and it’s an OS setting for processes, not specific to Java. On Linux: http://www.cyberciti.biz/tips/setting-processor-affinity-certain-task-or-process.html On Windows: http://www.addictivetips.com/windows-tips/how-to-set-processor-affinity-to-an-application-in-windows/ On Mac it doesn’t look like you can set it: https://superuser.com/questions/149312/how-to-set-processor-affinity-on-os-x

How can I tell reliably if a boost thread has exited its run method?

June 15, 2023 by Tarik

Since you can join a thread even after it has terminated, joinable() will still return true until you call join() or detach(). If you want to know if a thread is still running, you should be able to call timed_join with a wait time of 0. Note that this can result in a race condition … Read more

Application threads vs Service threads

June 15, 2023 by Tarik

Yes, a blocking operation in a Service will still block the application. Despite first appearances, Services are not simply for running tasks in the background. They are for running tasks with a lifecycle that is independent of the Activity lifecycle (IE, they may continue after the Activity is closed). A Service that starts and ends … Read more

Android Process Scheduling

June 14, 2023 by Tarik

The following list presents the different types of processes in order of importance (the first process is most important and is killed last): Foreground process Visible process Service process Background process Empty process Note: Android ranks a process at the highest level it can, based upon the importance of the components currently active in the … Read more