PHP StopWatch for Performance Measurement and Profiling

The stop watch will measure the time a given piece of code is executed. It will also make it possible to add as many stops as we need to compare times for different parts. Stops can be labeled.

/**
 * StopWatch class.
 *
 * @author Ivan Georgiev
 */
class ig_StopWatch {
	var $timeInit;
	var $timeStart;
	var $timeStop = array();
	var $stopLabels = array();
 
	function ig_StopWatch() {
		$this->timeInit = $this->getMicrotime();
	}
 
	function start() {
		$this->timeStart = $this->getMicrotime();
	}
 
	function stop($label = null) {
		$this->timeStop[] = $this->getMicrotime();
		$this->stopLabels[] = $label;
	}
 
	function toString() {
		$start = $this->getStartMs();
		$string = "Total time: " . ($this->getMicrotime() - $start) . "\n";
		$lastTime = $start;
		for ($i=0; $i<count($this->timeStop); $i++) {
			$thisTime = $this->timeStop[$i];
			$thisLabel = $this->stopLabels[$i];
			$elTime = $thisTime - $lastTime;
			$string .= "  $i";
			if (! is_null($thisLabel)) $string .= " ($thisLabel)";
			$string .= ": $elTime\n";
			$lastTime = $thisTime;
		}
		return $string;
	}
 
	function printResult() {
		print $this->toString();
	}
 
	/**
	 * @access private
	 */
	function getStartMs() {
		return (isset($this->timeStart) ) ? $this->timeStart : $this->timeInit;
	}
 
	/**
	 * @access private
	 */
	function getMicrotime(){
		list($usec, $sec) = explode(" ",microtime());
		return ((float)$usec + (float)$sec);
	}
}

Example:

$watch = new ig_GlobalStopWatch();
$watch->start();
load_customers();
$watch->stop("Load Customers");
calculate_balance();
$watch->stop("Calculate Balance");
apply_pending_transactions();
$watch->stop("Apply Transactions");
$watch->printResult();

The result from above might look like the following:

Total time: 0.15867686271667
  0 (Load Customers): 0.052696943283081
  1 (Calculate Balance): 0.052886962890625
  2 (Apply Transactions): 0.05298900604248

Most of the times we would like to have a global StopWatch and we do not care of creating instances of this watch. To address this case, we created a GlobalStopWatch class which provides only static methods for accessing singleton StopWatch instance.

/**
 * Static wrapper to a singleton StopWatch instance.
 *
 * @author Ivan Georgiev
 */
class ig_GlobalStopWatch {
 
	function Start() {
		$watch =& ig_GlobalStopWatch::StopWatchInstance();
		$watch->start();
	}
 
	function Stop($label = null) {
		$watch =& ig_GlobalStopWatch::StopWatchInstance();
		$watch->stop($label);
	}
 
	function ToString() {
		$watch =& ig_GlobalStopWatch::StopWatchInstance();
		return $watch->toString();
	}
 
	function PrintResult() {
		$watch =& ig_GlobalStopWatch::StopWatchInstance();
		$watch->printResult();
	}
 
	/**
	 * @return ig_StopWatch
	 * @access private
	 */
	function & StopWatchInstance() {
		static $instance = array();
		if (!isset($instance[0])) {
			$instance[0] =& new ig_StopWatch();
		}
		return $instance[0];
	}
}

Example:

ig_GlobalStopWatch::Start();
load_customers();
ig_GlobalStopWatch::Stop("Load Customers");
calculate_balance();
ig_GlobalStopWatch::Stop("Calculate Balance");
apply_pending_transactions();
ig_GlobalStopWatch::Stop("Apply Transactions");
ig_GlobalStopWatch::PrintResult();

The result from above might look like the following:

Total time: 0.15867686271667
  0 (Load Customers): 0.052696943283081
  1 (Calculate Balance): 0.052886962890625
  2 (Apply Transactions): 0.05298900604248