How to use the ltrace tool to trace PHP library function calls, ltrace library function_PHP tutorial

How to use the ltrace tool to track PHP library function calls, ltrace library function

The example in this article describes how to use the ltrace tool to track PHP library function calls. Share it with everyone for your reference, the details are as follows:

Perhaps you are already familiar with using strace to track system calls. Today we 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 following output:

% 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 takes up almost 95.02% of the execution time, and 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.

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