PHP underlying code optimization and performance improvement practice

PHP is an open source server scripting language widely used in the field of Web development. It is simple and easy to learn, powerful, and can be perfectly matched with many open source databases, etc., making it suitable for Web applications. Shine in development. However, during the development process, PHP performance issues often need to be considered. This article will introduce practical performance optimization and improvement of PHP, with specific code examples.

1. Code Optimization

For PHP performance optimization, the first task is to optimize the code. Specific optimization methods are as follows:

1. Reduce function calls

Function calls require adding new frames to the stack and saving the scene at the same time. These operations will occupy A lot of memory. Therefore, minimizing function calls can greatly improve the performance of PHP programs. The specific optimization method is as follows:

Example 1:

 // 未优化代码
 for ($i=0; $i<1000; $i++) {
     $result = strlen($str);
 }
 
 // 优化后代码
 $length = strlen($str);
 for ($i=0; $i<1000; $i++) {
     $result = $length;
 }

Example 2:

 // 未优化代码
 function getSum($a, $b)
 {
     return $a + $b;
 }
 
 for ($i=0; $i<1000; $i++) {
     $sum = getSum(1, 2);
 }
 
 // 优化后代码
 $sum = 3;
 for ($i=0; $i<1000; $i++) {
     $result = $sum;
 }

2. Passing parameters by reference

Transfer of function parameters It is a very time-consuming operation, especially when the function is called a lot. Therefore, try to use the method of passing parameters by reference to avoid repeated copying of variables and improve the performance of PHP programs. The specific optimization method is as follows:

Example 1:

 // 未优化代码
 function getSum($a, $b)
 {
     return $a + $b;
 }
 $result = getSum(1, 2);
 
 // 优化后代码
 function getSum($a, $b, &$result)
 {
     $result = $a + $b;
 }
 getSum(1, 2, $result);

Example 2:

 // 未优化代码
 function increase(&$a, $b)
 {
     $a += $b;
 }
 $x = 1;
 increase($x, 2);
 
 // 优化后代码
 function increase($a, $b)
 {
     $a += $b;
     return $a;
 }
 $x = increase(1, 2);

3. Use built-in functions as much as possible

provided by PHP It has many built-in functions and extensions. Using these built-in functions can maximize the performance of the program and also reduce the amount of code. The following are some examples of commonly used built-in functions to optimize code:

Example 1:

 // 未优化代码
 $arr = array(1, 2, 3);
 $max = max($arr);
 
 // 优化后代码
 $max = $arr[0];
 foreach ($arr as $value) {
     if ($value > $max) {
         $max = $value;
     }
 }

Example 2:

 // 未优化代码
 $str = '1,2,3,4,5';
 $arr = explode(',', $str);
 
 // 优化后代码
 $arr = array(1, 2, 3, 4, 5);

2. Performance improvement

Code optimization It can improve the performance of PHP programs, but it is not a panacea. When the program's running efficiency has reached a bottleneck, we have to consider other performance improvement methods. The following are some commonly used performance improvement methods:

1. Caching data

Data caching is a common performance improvement method that can avoid repeated queries to the database or repeated operations. Commonly used caching methods include file caching and memory caching. For specific implementation, caching technologies such as Memcache and Redis can be used. The following is an example of a memory cache:

 $memcache = new Memcache;
 $memcache->connect('localhost', 11211);
 $key = 'cache_key';
 $value = $memcache->get($key);
 if (!$value) {
     $value = fetchDataFromDb();
     $memcache->set($key, $value);
 }

2. Multiple processes

Multiple processes allow the program to handle multiple requests at the same time, reduce waiting time, and improve the concurrent performance of the program. For specific implementation, you can use PCNTL extension or tools such as Swoole. The following is an example of PCNTL multi-process:

 function doTask($taskid, $n)
 {
     echo "Task $taskid start...
";
     sleep($n);
     echo "Task $taskid done.
";
 }
 
 for ($i=0; $i<5; $i++) {
     $pid = pcntl_fork();
     if ($pid == -1) {
         die("fork error
");
     } elseif ($pid == 0) {
         doTask($i, rand(1, 5));
         exit(0);
     }
 }
 for ($i=0; $i<5; $i++) {
     pcntl_waitpid(-1, $status);
 }

3. Reduce file IO operations

File IO operations will occupy more CPU resources and I/O bandwidth, so try as much as possible Reducing file IO operations can improve program performance. Specific optimization methods are as follows:

Example 1: Avoid frequently opening and closing files

 // 未优化代码
 for ($i=0; $i<100; $i++) {
     $fp = fopen('file.txt', 'r');
     // ...
     fclose($fp);
 }
 
 // 优化后代码
 $fp = fopen('file.txt', 'r');
 for ($i=0; $i<100; $i++) {
     // ...
 }
 fclose($fp);

Example 2: Using the caching mechanism

 // 未优化代码
 $fp = fopen('file.txt', 'r');
 while (!feof($fp)) {
     $line = fgets($fp);
     // ...
 }
 fclose($fp);
 
 // 优化后代码
 $fp = fopen('file.txt', 'r');
 while ($line = fgets($fp)) {
     // ...
 }
 fclose($fp);

The above is the underlying code optimization of PHP The specific methods and code examples of actual performance improvement are hoped to help PHP developers better improve the performance of their programs. At the same time, in addition to the methods mentioned above, there are some other methods that can further improve the performance of the program, such as compiler optimization and hardware optimization. Therefore, in order to obtain better performance improvement effects, we need to comprehensively consider a variety of optimization methods based on specific circumstances.

The above is the detailed content of PHP underlying code optimization and performance improvement practice. For more information, please follow other related articles on the PHP Chinese website!