This demo shows how Swoole can handle 100 requests in parallel using 2 php processes.

server.php

<?php
/**
 * This demo shows how Swoole can handle
 * 100 requests in parallel using 2 php processes.
 *
 * Usage:
 * php server.php
 *
 * To confirm that we only have two worker processes:
 * ps a | grep swoole
 *   38947 pts/1    S+     0:00 php swoole event worker 0
 *   38948 pts/1    S+     0:00 php swoole event worker 1
 *
 * Benchmark to run 100 requests in parallel within 5 seconds:
 * (each request takes a sleep of 5 seconds)
 *
 * siege -c 100 -r 1 -b "http://127.0.0.1:9200/"
 *   ** SIEGE 4.0.4
 *   ** Preparing 100 concurrent users for battle.
 *   The server is now under siege...
 *   Transactions:                    100 hits
 *   Availability:                 100.00 %
 *   Elapsed time:                   5.02 secs
 *   Data transferred:               0.00 MB
 *   Response time:                  5.01 secs
 *   Transaction rate:              19.92 trans/sec
 *   Throughput:                     0.00 MB/sec
 *   Concurrency:                   99.75
 *   Successful transactions:         100
 *   Failed transactions:               0
 *   Longest transaction:            5.02
 *   Shortest transaction:           5.00
 *
 * In the output of "php server.php" we will see that all requests happen in parallel:
 *   starting worker 0
 *   starting worker 1
 *   0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
 *   1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111
 */

use Swoole\HTTP\Request;
use Swoole\HTTP\Response;
use Swoole\HTTP\Server;
use Swoole\Runtime;

error_reporting(E_ALL);
ini_set('display_errors', 'On');

Runtime::enableCoroutine(SWOOLE_HOOK_ALL);

$http = new Server("0.0.0.0", 9200, SWOOLE_PROCESS, SWOOLE_SOCK_TCP);
$http->set([
    'worker_num' => 2, // use 2 processes
    'reactor_num' => 2, // use 2 reactor threads
    'dispatch_mode' => 1, // 1 = round robin, 2 = fixed mode
    'log_level' => 4, // warning
]);

$http->on('WorkerStart', function (Server $server, int $workerId): void {
    cli_set_process_title('php swoole event worker ' . $workerId);
    echo 'starting worker ' . $workerId . PHP_EOL;
});

$http->on('request', function (Request $request, Response $response) use ($http): void {
    echo '0';
    sleep(5);
    echo '1';

    $response->end('<h1>Hello Swoole.</h1>' . $http->worker_id);
});

$http->start();