自作の処理時間計測ツールの紹介

<?php

class StopWatch
{
    private static $startTime;
    private static $lastTime;
    private static $total = 0;
    private static $log = [];

    public static function start($note = '')
    {
        $time = microtime(true);
        self::$startTime = $time;
        self::$lastTime  = $time;
        self::log(0, self::note($note));
    }

    public static function lap($note = '')
    {
        $time = microtime(true);
        $lap = $time - self::$lastTime;
        self::$lastTime = $time;
        self::$total = $time - self::$startTime;
        self::log($lap, self::note($note));
    }

    public static function stop($note = '')
    {
        $time = microtime(true);
        $lap = $time - self::$lastTime;
        self::$total = $time - self::$startTime;
        self::log($lap, self::note($note));
    }

    /** @return array */
    public static function getLog()
    {
        return self::$log;
    }

    private static function log($lap, $note)
    {
        self::$log[] = [
            'total' => sprintf('%.6f', self::$total),
            'lap'   => sprintf('%.6f', $lap),
            'note'  => $note,
        ];
    }

    private static function note($note)
    {
        $dbg = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1];

        if ($note !== '') {
            $note .= ' ';
        }

        $note .= "{$dbg['file']}#{$dbg['line']}";

        return $note;
    }
}

<?php

StopWatch::start();
usleep(1000);
StopWatch::lap();
usleep(1000);
StopWatch::lap('コメントも書ける');
usleep(1000);
StopWatch::stop();
var_dump(StopWatch::getLog());

// 結果
// array(4) {
//   [0]=>
//   array(3) {
//     ["total"]=>
//     string(8) "0.000000"
//     ["lap"]=>
//     string(8) "0.000000"
//     ["note"]=>
//     string(21) "/workspace/Main.php#3"
//   }
//   [1]=>
//   array(3) {
//     ["total"]=>
//     string(8) "0.001090"
//     ["lap"]=>
//     string(8) "0.001090"
//     ["note"]=>
//     string(21) "/workspace/Main.php#5"
//   }
//   [2]=>
//   array(3) {
//     ["total"]=>
//     string(8) "0.002160"
//     ["lap"]=>
//     string(8) "0.001070"
//     ["note"]=>
//     string(46) "コメントも書ける /workspace/Main.php#7"
//   }
//   [3]=>
//   array(3) {
//     ["total"]=>
//     string(8) "0.003232"
//     ["lap"]=>
//     string(8) "0.001072"
//     ["note"]=>
//     string(21) "/workspace/Main.php#9"
//   }
// }