getopt
getrusage() reports kernel counters that are updated only once application loses context and a switch to kernel space happens. For example on modern Linux server kernels that would mean that getrusage() calls would return information rounded at 10ms, desktop kernels - at 1ms.
getrusage() isn't usable for micro-measurements at all - and getmicrotime(true) might be much more valuable resource.
getrusage
(PHP 4, PHP 5)
getrusage — 获取当前资源使用状况
说明
array getrusage
([ int
$who = 0
] )这是 getrusage(2) 的接口。它返回了调用自系统的数据。
参数
-
who -
如果
who是 1，getrusage 会使用RUSAGE_CHILDREN来调用。
返回值
返回了一个包含系统返回数据的关联数组。所以条目均可通过文档中字段的名称来访问。
范例
Example #1 getrusage() 例子
<?php
$dat = getrusage();
echo $dat["ru_nswap"]; // number of swaps
echo $dat["ru_majflt"]; // number of page faults
echo $dat["ru_utime.tv_sec"]; // user time used (seconds)
echo $dat["ru_utime.tv_usec"]; // user time used (microseconds)
?>
注释
Note: 此函数未在 Windows 平台下实现。
参见
- 你系统上 getrusage(2) 的 man page
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User Contributed Notes
getrusage - [2 notes]
Domas Mituzas ¶
5 years ago
php at lavrenko dot pp dot ru ¶
7 years ago
The author of the article mentioned in the previous post says "Once I got a negative value for both times - I have absolutely no clue how that can happen.". This is because time in microseconds is not padded with zeros from the left, therefore, you cannot concatenate the two numbers. Instead, you should normalize the values and then add them up:
$dat["ru_utime.tv_sec"]*1e6+$dat["ru_utime.tv_usec"];