my-test-dir-size.php

add_action( 'plugins_loaded', '_my_dir_test' );
function _my_dir_test() {
	// dir size test
	$start_execution_time = microtime( true );
	$max_execution_time = 20;
	$uploads_dir = wp_upload_dir();

	for ( $i = 0; $i < 50; $i++ ) {
		$calculated_size = _my_get_directory_size( ABSPATH, $max_execution_time, $start_execution_time );
	}

	echo 'RecursiveDirectoryIterator ABSPATH size 50 times: t = ' . ( microtime( true ) - $start_execution_time ) . ', size = ' . $calculated_size . '<br>';

	$start_execution_time = microtime( true );
	for ( $i = 0; $i < 50; $i++ ) {
		$calculated_size = get_dirsize( ABSPATH );
	}

	echo 'get_dirsize() ABSPATH size 50 times: t = ' . ( microtime( true ) - $start_execution_time ) . ', size = ' . $calculated_size . '<br>';
	exit;
}


function _my_get_directory_size( $path, $max_execution_time, $start_execution_time ) {
	$size = 0;

	foreach ( new RecursiveIteratorIterator( new RecursiveDirectoryIterator( $path ) ) as $file ) {
		// Check if the maximum execution time is a value considered "infinite".
		if ( 0 !== $max_execution_time && -1 !== $max_execution_time ) {
			$runtime = ( microtime( true ) - $start_execution_time );

			// If the script has been running as long, or longer, as it is allowed, return a failure message.
			if ( $runtime >= $max_execution_time ) {
				return -1;
			}
		}
		$size += $file->getSize();
	}

	return $size;
}