Avoid double calculations: High-performance programming in PHP

In the field of web development, PHP as a dynamic language is widely used to build websites and web applications. However, due to the design issues of the PHP language itself, its performance may be affected to a certain extent compared to other programming languages. In high-concurrency web applications, optimizing the performance of PHP programs is often an important task. This article will introduce some optimization techniques to help PHP developers write high-performance PHP code.

1. Avoid double calculations

A common performance problem is double calculations. In PHP code, this usually happens when using a loop to process a set of data. If the data size is large, it can cause performance issues. A simple solution is to use a cache (e.g. $cache variable) to store the calculation results for each loop iteration to avoid performing the same calculation repeatedly. This technique can greatly reduce the running time of PHP programs, thus improving performance.

Example:

$cache = array();
foreach($data as $value) {
if(array_key_exists($value, $cache)) {

$result = $cache[$value];

} else {

$result = complex_function($value);
$cache[$value] = $result;

}
// Process calculation results
}

2. Use OPcache

OPcache is A built-in caching mechanism of PHP, which can cache PHP compiled code into memory to avoid repeatedly compiling the same script when PHP is executed, improving the operating efficiency of PHP programs. For better performance, developers should enable OPcache and optimize it in settings.

Example:

[opcache]
opcache.enable = 1
opcache.memory_consumption = 256
opcache.max_accelerated_files = 20000

3. Avoid garbage collection

PHP's garbage collection mechanism can reclaim memory space that is no longer used for storing other variables. However, when concurrency is high, garbage collection can become a performance bottleneck, causing CPU cycles to be wasted. In order to avoid this situation, developers can use the unset() function to actively release variables and objects that are no longer used and reclaim memory in a timely manner.

Example:

$variable = 'some text';
unset($variable);

4. Use multiple CPU cores

Multi-core CPU has been the mainstream configuration of computers in recent years. The release of PHP 7 adds support for multi-threading, allowing PHP developers to use multiple CPU cores to speed up program execution. PHP developers can develop web applications that support multi-threading based on the open source Swoole framework (http://www.swoole.com/).

Example:

$server = new SwooleServer("0.0.0.0", 9501, SWOOLE_PROCESS, SWOOLE_SOCK_TCP);

$server-> ;set(array(

'reactor_num' => 2,
'worker_num' => 4,
'backlog' => 128,

));

$server->on('Connect', function ($serv, $fd) {

echo "Client: {$fd} Connect.

";
});

$server->on('Receive', function ($serv, $fd, $from_id, $data) {

$serv->send($fd, 'Swoole: ' . $data);

});

$server->on('Close', function ($serv, $fd) {

echo "Client: {$fd} Close.

";
});

$server-> start();

5. Use the latest version of PHP

PHP is constantly updated and iterated to optimize its performance and functionality. Update PHP to the latest version for optimal performance and to take advantage of new features. PHP7 and PHP8 offer higher performance than previous PHP versions.

Conclusion

As a dynamic language, PHP has the advantages of ease of use and flexibility, but there are also certain performance bottlenecks. Optimizing the performance of PHP programs requires developers to be proficient in the characteristics of PHP and adopt corresponding optimization strategies based on the actual situation. By operating it, the performance and response speed of PHP can be greatly improved.

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