计算php执行时间

	header('Content-Type: text/html; charset=utf-8;');

	//计算执行时间
	function G($start='start',$end=''){
		static $time=array();
		if($end == 'get'){
			return $time[$start];	
		}
		if($end !=''){
			return sprintf('%.3f',($time[$end] - $time[$start])*1000).'毫秒';	
		}else{
			$tmp = explode(' ',microtime());
			$time[$start] = $tmp[1]+$tmp[0];
			return $time[$start];	
		}
	}
	G('start');
	$str = 0;
	for($i=0;$i++;$i<1000000){ $i; } G('end'); echo " ".'开始时间：'.G('start','get'); echo " ".'结束时间：'.G('end','get'); echo " ".'执行时间：'.G('start','end'); 


	//优化时间
	function format_time($time){
		if($time>1000){
			return sprintf("%.3f",$time/1000).'秒';	
		}else{
			return sprintf("%.3f",$time).'毫秒';	
		}
	}
	//计算执行时间
	function G($start='start',$end=''){
		static $time=array();
		if($end == 'get'){
			return $time[$start];	
		}
		if($end !=''){
			return format_time(sprintf('%.3f',($time[$end] - $time[$start])*1000));	
		}else{
			$tmp = explode(' ',microtime());
			$time[$start] = sprintf('%.6f',$tmp[1]+$tmp[0]);
			return $time[$start];	
		}
	}
	G('start');
	$str = '';
	for($i=0;$i<3;$i++){
		$str .= file_get_contents('http://www.yetyun.com');	
	}
	G('end');
	echo "
".'开始时间：'.G('start','get');
	echo "
".'结束时间：'.G('end','get');
	echo "
".'执行时间：'.G('start','end');