See also https://github.com/wikimedia/less.php/issues/104

lessphp5-cache-bench.php

#!/usr/bin/env php
<?php

require_once __DIR__ . '/lib/Less/Autoloader.php';
Less_Autoloader::register();

$opt = [
	'cache_dir' => '/tmp/lessphp-example'
];
$input = __DIR__ . '/test/Fixtures/bootstrap-3.2/less/bootstrap.less';
$uri_root = '/assets/boostrap';
$fileToUri = [ $input => $uri_root ];

const ITERATIONS = 10;

function measure(string $label, $fn) {
	// Use child processes so that each has its own peak memory
	$pid = pcntl_fork();
	if ($pid) {
		// main
		return;
	}

	// Warmup
	$fn();

	$t = hrtime(true);
	for ($i = 0; $i < ITERATIONS; $i++) {
		$fn();
	}
	$durationNanos = hrtime(true) - $t;

	$durationMs = round( $durationNanos * 1e-6 );
	$peakMemMiB = memory_get_peak_usage() / 1024 / 1024;

	print sprintf( "%s: %.2f ms, %.2f MiB\n",
		$label,
		( $durationMs / ITERATIONS ),
		$peakMemMiB
	);

	exit;
}

measure('Less_Cache', fn () => Less_Cache::Get($fileToUri, $opt));
pcntl_wait($status);

measure('Less_Parser-nocache', static function () use ($opt, $input, $uri_root) {
	Less_Cache::$cache_dir = false;
	$parser = new Less_Parser([ 'cache_dir' => null ] + $opt);
	$parser->parseFile($input, $uri_root);
	$parser->getCss();
} );
pcntl_wait($status);

measure('Less_Parser-cache', static function () use ($opt, $input, $uri_root) {
	$parser = new Less_Parser($opt);
	$parser->parseFile($input, $uri_root);
	$parser->getCss();
} );
pcntl_wait($status);