追踪php代码性能瓶颈
写了一段很简单的代码示例，却发现运行起来速度很慢，出现性能问题的代码量并不大，排除了IO问题以后，写了一段测试代码，果然问题很快重现。 ?php$y="1800";$x = array();for($j=0;$j[root@xp trace]# time php test.phpreal 0m4.116suser 0m4.070ssys 0m0.
写了一段很简单的代码示例，却发现运行起来速度很慢，出现性能问题的代码量并不大，排除了IO问题以后，写了一段测试代码，果然问题很快重现。
<?php $y="1800"; $x = array(); for($j=0;$j [root@xp trace]# time php test.php real 0m4.116s user 0m4.070s sys 0m0.028s
可以看出时间耗掉了4秒，下面用strace跟踪没拿到什么有效信息。
[root@xp trace]# strace -ttt -o log.txt php test.php [root@xp trace]# more log.txt
只看到这两次系统调用之间的延时非常大，却并不知道干了什么？一筹莫展了，幸好，Linux下的调试利器除了strace还有ltrace(当然还有dtrace，ptrace)。
引用：strace用来 跟踪一个进程的系统调用或信号产生的情况，而 ltrace用来 跟踪进程调用库函数的情况(via?IBM developerworks)。
[root@xp trace]# ltrace -c php test.php
我们看到库函数strtol的调用非常之频繁，太夸张了，然后我又查了一下这个库函数，简单的说就是把字符串转换成长整形，可以猜测PHP引擎已经检测到这是一个字符串型的数字，所以期望将他们转换成长整型来比较，这个转换过程中消耗了太多时间，我们再次执行:
[root@xp trace]# ltrace -e "strtol" php test.php (0, 0, 0xec4b00, -1, 0x1f25bc2) = 0x32dd221160 strtol(0x1c9f9d0, 0, 10, 0, 0x7fffe64537f0) = 8 strtol(0x1c9f9b0, 0, 10, 0x7fffe6453880, 0x7fffe64537f0) = 30719 strtol(0x1c9f9d0, 0, 10, 0x32ddb8ee88, 0x32ddb8d580) = -9 strtol(0x1c9f070, 0, 10, 371, 0x10119a0) = 0 strtol(0x1c9ea90, 0, 10, 370, 0x10119a0) = 0 strtol(0x1c9e580, 0, 10, 81, 0x1010c60) = 1 strtol(0x1c9fae0, 0, 10, 82, 0x1010c60) = 0 strtol(0x1ca0cf0, 0, 10, 26, 0x1010c60) = 0 strtol(0x1c9f7a0, 0, 10, 408, 0x1010c60) = 0 strtol(0x1c9e6d0, 0, 10, 432, 0x1010c60) = 0 strtol(0xcea563, 0, 10, 433, 0x1010c60) = 0 strtol(0xcea563, 0, 0, 440, 0x1010c60) = 0 strtol(0x1c9f8f0, 0, 0, 72, 0x1010c60) = -1 strtol(0xcea563, 0, 10, 298, 0x1010c60) = 0 strtol(0x1c9ee50, 0, 10, 5, 0x1010c60) = 1 strtol(0x1c9fb80, 0, 10, 83, 0x1010c60) = 1 strtol(0x1c9fc30, 0, 0, 88, 0x1010c60) = 1024 strtol(0x1c9fce0, 0, 10, 96, 0x1010c60) = 0 strtol(0x1c9fd90, 0, 10, 97, 0x1010c60) = 0 strtol(0x1c9f330, 0, 10, 98, 0x1010c60) = 1 strtol(0x1c9e4d0, 0, 10, 461, 0x1010c60) = 0 strtol(0x1ca05a0, 0, 10, 0, 0x1010c60) = 0 strtol(0x1ca0650, 0, 10, 1, 0x1010c60) = 0 strtol(0x1ca0700, 0, 10, 2, 0x1010c60) = 0 strtol(0x1c9ec70, 0, 0, 8, 0x1010c60) = 0 strtol(0x1ca03c0, 0, 10, 411, 0x1010c60) = 1 strtol(0x1ca0260, 0, 10, 409, 0x1010c60) = 0 strtol(0x1ca0310, 0, 10, 410, 0x1010c60) = 0 strtol(0x1ca0460, 0, 10, 412, 0x1010c60) = 1 strtol(0x1c9f130, 0, 10, 3, 0x1010c60) = 0 strtol(0x1c9f1d0, 0, 10, 24, 0x1010c60) = 0 strtol(0x1c9e9f0, 0, 10, 369, 0x10119a0) = 1 strtol(0x1c9feb0, 0, 10, 25, 0x1010c60) = 0 strtol(0x1c9f3d0, 0, 10, 80, 0x1010c60) = 0 strtol(0x1c9ebd0, 0, 10, 413, 0x1010c60) = 1 strtol(0x1c9efe0, 0, 0, 48, 0x1010c60) = 17 strtol(0x1c9f850, 0, 10, 0, 0) = 0 strtol(0x1ca0d90, 0, 10, 457, 0x1010c60) = 1 strtol(0x1ca0e40, 0, 0, 160, 0x1010c60) = 1000 strtol(0x1ca0500, 0, 0, 432, 0x1010ec0) = 1000 strtol(0xd214c5, 0, 0, 520, 0x1010c60) = 64 strtol(0xd37961, 0, 0, 584, 0x1010c60) = 1000 strtol(0x1ca1250, 0, 10, 560, 0x1010c60) = 1 strtol(0x1c9f990, 0, 0, 0, 0) = 512 strtol(0x1c9eb30, 0, 10, 0, 0) = 14 strtol(0x1ca0f80, 0, 10, 459, 0x1010c60) = 1 strtol(0x1ca1030, 0, 10, 512, 0x1010c60) = 0 strtol(0xcea563, 0, 10, 460, 0x1010c60) = 0 strtol(0xd37a32, 0, 0, 24, 0x100ec20) = 16 strtol(0xd37a49, 0, 0, 32, 0x100ec20) = 120 strtol(0xd37a7c, 0, 0, 544, 0x1010c60) = 300 strtol(0xcea563, 0, 10, 513, 0x1010c60) = 0 strtol(0x1c9ef30, 0, 10, 0, 0) = 30711 strtol(0x1c9f700, 0, 10, 0, 0x1011d80) = 1 (0x32dd221160, 0, 0, 0x32dd221160, 0) = 531783 (0, 0, 0, 15, 0x42622d0) = 0x32dd221160 (0x32dd221160, 0, 0, 0x32dd221160, 0) = 531720 (0, 0, 0, 11, 0x7f9fa7b51b80) = 0x32dd221160 (0x32dd221160, 0, 0, 0x32dd221160, 0) = 531719 (0, 0, 0, 6, 0x9275f60) = 0x32dd221160 (0x32dd221160, 0, 0, 0x32dd221160, 0) = 531897 (0, 0, 0, 9, 0x7f9fa74b8338) = 0x32dd221160 (0x32dd221160, 0, 0, 0x32dd221160, 0) = 531901 (0, 0, 0, 3, 0x7f9fa72a8340) = 0x32dd221160 (0x32dd221160, 0, 0, 0x32dd221160, 0) = 532944 (0, 0, 0, 3, 0x7f9fa70641d0) = 0x32dd221160 (0x32dd221160, 0, 0, 0x32dd221160, 0) = 525536 (0, 0, 0, 3, 0x7f9fa6e5c680) = 0x32dd221160 .....
知道了症结所在，我们解决的办法就很多了，最简单的就是为in_array加第三个参数为true，即变为严格比较，同时还要比较类型，这样避免了PHP自作聪明的转换类型，跑起来果然快多了。
[root@xp trace]# time php test.php real 0m0.988s user 0m0.959s sys 0m0.024s
写了一段很简单的代码示例，却发现运行起来速度很慢，出现性能问题的代码量并不大，排除了IO问题以后，写了一段测试代码，果然问题很快重现。 可以看出时间耗掉了4秒，下面用strace跟踪没拿到什么有效信息。 只看到这两次系统调用之间的延时非常大，却并不知道干了什么？一筹莫展了，幸好，Linux下的调试利器除了strace还有ltrace(当然还有dtrace，ptrace)。 引用：strace用来 跟踪一个进程的系统调用或信号产生的情况，而 ltrace用来 跟踪进程调用库函数的情况(via?IBM developerworks)。 我们看到库函数strtol的调用非常之频繁，太夸张了，然后我又查了一下这个库函数，简单的说就是把字符串转换成长整形，可以猜测PHP引擎已经检测到这是一个字符串型的数字，所以期望将他们转换成长整型来比较，这个转换过程中消耗了太多时间，我们再次执行: 知道了症结所在，我们解决的办法就很多了，最简单的就是为in_array加第三个参数为true，即变为严格比较，同时还要比较类型，这样避免了PHP自作聪明的转换类型，跑起来果然快多了。
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian
Dec 24, 2024 pm 04:42 PM
PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati
Explain JSON Web Tokens (JWT) and their use case in PHP APIs.
Apr 05, 2025 am 12:04 AM
JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,
How do you parse and process HTML/XML in PHP?
Feb 07, 2025 am 11:57 AM
This tutorial demonstrates how to efficiently process XML documents using PHP. XML (eXtensible Markup Language) is a versatile text-based markup language designed for both human readability and machine parsing. It's commonly used for data storage an
Explain late static binding in PHP (static::).
Apr 03, 2025 am 12:04 AM
Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.
PHP Program to Count Vowels in a String
Feb 07, 2025 pm 12:12 PM
A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total
What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases?
Apr 03, 2025 am 12:03 AM
What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.
PHP and Python: Comparing Two Popular Programming Languages
Apr 14, 2025 am 12:13 AM
PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.
PHP: A Key Language for Web Development
Apr 13, 2025 am 12:08 AM
PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7
