How to use the ltrace tool to trace PHP library function calls

The example in this article describes how to use the ltrace tool to trace PHP library function calls. I share it with you for your reference. The details are as follows:

Maybe you are already familiar with using strace to track system calls. Today I introduce a powerful tool for tracking library functions, ltrace

For example, I have this piece of PHP code

test.php:

<&#63;php
 $y = '1380';
 $arr = array();
 for($i = 0; $i < 2000; $i ++){
   $arr[] = "{$i}"; //故意用引号包起来设成字符串
 }
 for($i = 0; $i < 2000; $i ++){
   if(!in_array($y, $arr)) continue;
 }
&#63;>

ltrace -c /usr/local/php/bin/php test.php (-c means summary)

You will see the output as follows:

% time   seconds usecs/call   calls   function
------ ----------- ----------- --------- --------------------
95.02  7.417240     368   20146 strtol
2.15  7.160390     413   17316 memcpy
1.63  5.522641     240   22966 free
 0.67  2.275374   2275374     1 curl_global_cleanup
 0.54  2.235466     617   3618 __ctype_tolower_loc
 0.16  2.123547    1194   1778 strrchr
 0.17  1.532224     67   22836 malloc
 0.29  0.382083     67   5678 strlen

You can see that strtol almost uses up the execution time 95.02%, the bottleneck is found. And PHP will try to convert the string number into a long during the in_array() test, which will take a lot of time. Therefore, as long as all strings are converted into integers, the efficiency can be greatly improved.

ltrace is really a good tool

I hope this article will be helpful to everyone in PHP programming.

The above introduces the method of using the ltrace tool to track PHP library function calls, including trace content. I hope it will be helpful to friends who are interested in PHP tutorials.