Explanation of theoretical knowledge of PHP performance optimization

The content of this article is to explain the theoretical knowledge about PHP performance optimization. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

Under what circumstances do you encounter PHP performance problems?

1 Improper use of PHP syntax
2 Use PHP language to do things it is not good at
3 Services connected using php language are not powerful
4 PHP itself Shortcomings
5 Problems I don’t know either

Performance problem analysis

PHP performance problems account for less than 50% of the entire project’s performance problems

Performance optimization projects, don’t be limited to optimizing only PHP

php language-level performance optimization
                                                                               #                                                                                                          Download by yourself)
ab is a stress testing software provided by Apache. This stress testing software will be included when installing the apache server.

how to use?

./ab -n1000 -c100 http://www.baidu.com/
-n number of requests
-c number of concurrency

url target stress test addressPHP-Stress Testing Tool Usage Demonstration

Mainly focus on as many concurrencies as possible per second

Request time-consuming as little as possible

Use more of PHP's own capabilities

Optimization: write less code and use more of PHP's own capabilities

Performance issues: The own code is redundant, has poor readability, and has low performance

It's very performance Low?

PHP code needs to be compiled and parsed into the underlying language. This process will be processed for each request, which is expensive.

Good method:

Use more PHP built-in variables\constants\functions

Code preparation for PHP's own ability performance test

php code running process

*.php ---Scanner---> Exprs -----Parser--->Opcodes---Exec--->Output

Performance test between php built-in functions

Optimization point: Performance advantages and disadvantages of php built-in functions

Situation description: There are still blocks between php built-in functions Slow difference

Good suggestions: Learn more about the time complexity of PHP built-in functions

Performance testing between PHP built-in functions and code testing

isset($arr[$i]); //平均50ms
array_key_exists($i,$arr);//平均85ms

Reduce PHP magic functions Description of usage: The magic function provided by PHP has poor performance

Why is the performance low? In order to save PHP programmers trouble, the PHP language has done a lot for you

Okay Method: Avoid using PHP magic functions as much as possible

PHP Disable error suppressor

@The actual logic

Add Opcode before and after the start of the code Ignore the error

php -dv|d.active=1 -dv|d.execute=0 at.php

Just want to check and not really want to execute

PHP-reasonable use of memory and regular expressions

Optimization point: Reasonable Using memory

PHP has a memory recycling mechanism to guarantee, but please be careful when using memory

Good suggestions

Use unset() to release unused memory in time (Note: unset () If the logout fails)
Use regular expressions as little as possibleThe backtracking overhead of regular expressions is relatively large,

Good suggestions:

Use string processing functions to implement the same logic

PHP-Avoid doing operations within the loop

Optimization point: Avoid doing operations within the loop

Situation description:

The calculation formula within the loop will be repeatedly calculated

Code example:

<?php
$str = "hello world";
for($i=0;$i<strlen($str);$i++)
{
    //do something
}

PHP-Reduce calculation-intensive business

PHP does not Suitable for intensive computing scenarios

PHP language characteristics determine that PHP is not suitable for large data volume operations

PHP is suitable for scenarios

Suitable for connecting Webserver and backing services, UI presentation

PHP-Be sure to use quoted strings as key values

PHP will treat key values ​​without quotes as constants, resulting in the cost of finding constants

Strictly use quoted strings As a key value

Analysis and explanation of issues surrounding PHP

What are the surrounding areas of PHP?

linux operating environment php Hard disk (file storage) database (such as mysql) cache network

Analysis of the impact of PHP peripherals on PHP programs

Reduce file operations

Overhead sequence of common PHP scenarios: Read and write disk, read and write database, read and write memory, read and write network data

read and write memoryca991931dbba0a83476a3a4a658ba221 Process1 ->process2 ->process3 -> process4->

Bypass solution: x.php -> Process1 ->process2 (simultaneously) ->Process3 (simultaneously) -->Process4->

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