PHP performance optimization - PHP language-level performance optimization - PHP tutorial

php performance optimization php language-level performance optimization 1

For this problem, first we need to know what is the reason that affects the performance of php? That is

1 Under what circumstances will PHP performance problems occur?

1ｐｈｐ Improper use of syntax (including some businesses that can be processed using PHP’s own functions)

2 Use php language to do things it is not good at

3 The server connected using php language is not powerful (of course, if it is localhost, your local configuration is relatively poor, it is recommended to change it, haha)

4php’s own shortcomings (PHP itself can’t do it)

5 Questions We Don’t Know (囧)

2 Introduction to PHP performance issues and solutions to PHP performance issues

From the least difficult to the most difficult are:

1 Php language level performance optimization

2 Performance optimization of Php peripheral issues (such as mysql nginx|apache)

3 Php language senior analysis and optimization (ps mainly refers to the underlying c code)

The following is an example discussion of PHP language-level performance optimization, and a test of the content mentioned in the title. Next, we need to write two files bad.php, goods.php

What we want to test is the operation of merging two arrays (test tool apache ab test)

bad.php

Things:

First add array 1 to the target array one by one;

After

, traverse array 2 and compare whether the elements of array 2 appear in array 1. If not, insert them into the target array, otherwise ignore

<span style="font-size:14px;"><?php
//准备两个内容随机的数组
$arr1 = $arr2 = $arr_merged = array();
//接下来随机给两个数组赋值
for ( $i=0; $i<rand(1000,2000); $i++) {
	$arr1[] = rand();
}

for ( $i=0; $i<rand(1000,2000); $i++) {
	$arr2[] = rand();
}

//开始循环比较
foreach ( $arr1 as $v ) {
	$arr_merged[]  = $v;
}

foreach ( $arr2 as $v ) {
	if(!in_array($v, $arr_merged)){
		$arr_merged[]  = $v;
	}
}

var_dump($arr_merged);</span>

goods.php

Things:

Randomly generate two arrays and shuffle them in order

After that, use array_merge to merge

<span style="font-size:14px;"><?php
//准备两个内容随机的数组
$arr1 = $arr2 = range(1000, 2000);
$arr_merged = array();
//接下来随机给两个数组赋值
shuffle($arr1);
shuffle($arr2);

$arr_merged = array_merge($arr1, $arr2);

var_dump($arr_merged);
</span>

3 Use ab to test the speed of two php scripts: (ps: the amazing moment begins)

bad.php

goods.php喎?http://www.Bkjia.com/kf/ware/vc/" target="_blank" class="keylink">vcD4KPHA+PGltZyBzcmM9"http://www.2cto.com/uploadfile/Collfiles/20141205/20141205084010231.png" alt="">

For these two tests, we can clearly see that the difference is not a little bit different. When executing bad.php, I obviously felt the computer fan blowing. You know!

bad.php responds to 174 requests per second, processing 572ms per request

goods.php responds to 4050 requests per second, processing 24ms per request

ps: If you still use the bad wording, change it as soon as possible, and be careful not to let your boss know!

4 The reason

I am also surprised by this result, but the facts are right in front of me and there is nothing we can do about it. So why is there such an effect? ​​Let’s continue to find out:

*.php (php code) -----Scanner (zend engine scans line by line into syntax that zend can recognize) ----> exprs

-----parser(parse to opcode)-----> opcodes ------exec(execute final output)-------> output

You can know that a PHP file needs to be scanned first to execute zend, and then parsed into opcode for execution output. The problem lies here. When we use PHP’s own functions, it actually belongs to the zend engine, so zend is relatively easy to parse. It's smooth and fast (goods.php), but when bad.php is executed, it will be slower, because reading code written by others is definitely not as fast as reading code written by yourself, right? So I still use the original one. It’s better not to make your own wheels!

To tell you a little more, this is why many Php extensions (such as apc) now cache opcodes because this eliminates the need for scanning and parsing, which is definitely faster!

5 Summary

Optimization points: write less code and use more capabilities provided by PHP itself

Performance issues:

The code I wrote is redundant, not readable, and has low performance

Why is the performance low?

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

Good method:

Use more PHP built-in variables, constants, and functions (spl can bring you useful functions)

http://www.bkjia.com/PHPjc/925221.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/925221.htmlTechArticlephp performance optimization of php language-level performance optimization - For this problem, first of all, we need to know the reasons that affect the performance of php What is it? That is 1 Under what circumstances will PHP performance problems occur? ...