multithreading.md

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Multithreading

How is multitasking accomplished?

PHP

By extending the Thread class in the pthreads API. It should be noted that by most defaults, PHP will be compiled as thread-safe and without pthreads. It requires a non-negligible amount of work to both recompile or obtain a version of PHP will threading enabled, and the pthreads API installed.

Python

By subclassing the Thread class from the threading library, which is native to Python.

How do threads or thread-like abilities work?

PHP

Parallel threading in PHP is less elegant than in Python, but ultimately just as functional. A parallel threading system in a basic form can look something like this:

<?php
    class myThread extends Thread {
        private $id;
        public function __construct($id) {
            $this->id = $id;
        }
        public function run() {
            $sleepTime = mt_rand(1, 5);
            print "Thread with id ".$id."sleeping for ".$sleepTime." seconds";
            sleep($sleepTime);
            print "Thread with id ".$id." is ending";
        }
    }
    
    $threads = array();
    foreach(range(0, 10) as $i) {
        $threads[] = new myThread($i);
    }
    
    foreach($threads as $t) {
        $t->run();
    }
?>

Python

Python's threading capabilities are dense and very well documented. A basic parallel threading system can look something like this:

import time
import random
from threading import Thread

def myThreadedMethod(id):
    sleepTime = random.randint(1, 5)
    print("Thread with id %d is sleeping for %d seconds"%(id, sleepTime))
    time.sleep(sleepTime)
    print("Thread with id %d is ending"%(id))

for i in range(0, 10):
    t = Thread(target=myThreadedMethod, args=(i,))
    t.start()

Which will output:

Thread with id 0 is sleeping for 2 seconds
Thread with id 1 is sleeping for 3 seconds
Thread with id 2 is sleeping for 5 seconds
Thread with id 3 is sleeping for 5 seconds
Thread with id 4 is sleeping for 3 seconds
Thread with id 5 is sleeping for 2 seconds
Thread with id 6 is sleeping for 5 seconds
Thread with id 7 is sleeping for 2 seconds
Thread with id 8 is sleeping for 2 seconds
Thread with id 9 is sleeping for 1 seconds

Thread with id 9 is ending
Thread with id 0 is ending
Thread with id 5 is ending
Thread with id 8 is ending
Thread with id 7 is ending
Thread with id 1 is ending
Thread with id 4 is ending
Thread with id 2 is ending
Thread with id 3 is ending
Thread with id 6 is ending

Note how the threads end at the end of their execution, not necessarily in the same order they were spawned. This demonstrates how all threads were running in parallel.