提高php程序性能和负载测试

$start_time = microtime(true);

//一些需要计算时间的代码
//... code here ...

print('代码的运行时间是：'.getExecTime($start_time));

function getExecTime($start_time)
{
 return microtime(true)-$start_time;
}PEAR的Benchmark模块提供了更详细的时间统计功能

require_once 'Benchmark/Timer.php';
$timer =& new Benchmark_Timer(true);
$timer->start();
// 设置函数
$timer->setMarker('setup');
// some more code executed here
$timer->setMarker('middle');
// even yet still more code here
$timer->setmarker('done');
// and a last bit of code here
$timer->stop();
$timer->display();通过declare结构和ticks指令可以实现自动记录每一行PHP代码执行的时间

// A function that records the time when it is called
function profile($dump = FALSE)
{
    static $profile;

    // Return the times stored in profile, then erase it
    if ($dump) {
        $temp = $profile;
        unset($profile);
        return ($temp);
    }

    $profile[] = microtime();
}

// Set up a tick handler
register_tick_function("profile");

// Initialize the function before the declare block
profile();

// Run a block of code, throw a tick every 2nd statement
declare(ticks=2) {
    for ($x = 1; $x < 50; ++$x) {
        echo similar_text(md5($x), md5($x*$x)), ";";
    }
}

// Display the data stored in the profiler
print_r(profile (TRUE));注意：ticks 指令在 PHP 5.3.0 中是过时指令，将会从 PHP 6.0.0 移除。