php教程

php手册

hrtime

(PHP 7 >= 7.3.0)

hrtime — Get the system's high resolution time

说明

hrtime ([ bool $get_as_number = FALSE ] ) : mixed

Returns the system's high resolution time, counted from an arbitrary point in time. The delivered timestamp is monotonic and can not be adjusted.

参数

get_as_number: Whether the high resolution time should be returned as array or number.

返回值

Returns an array of integers in the form [seconds, nanoseconds], if the parameter get_as_number is false. Otherwise the nanoseconds are returned as integer (64bit platforms) or float (32bit platforms).

范例

Example #1 hrtime() usage


<?php
echo hrtime(true), PHP_EOL;
print_r(hrtime());
?>

以上例程的输出类似于：

10444739687370679
Array
(
    [0] => 10444739
    [1] => 687464812
)

参见

The High resolution timing extension

User Contributed Notes

SenseiSimple 25-Oct-2018 12:52


This function is particularly necessary on VMs running on KVM, XEN (openstack, AWS EC2, etc) when timing execution times. 



On these platforms which lack vDSO the common method of using time() or microtime() can dramatically increase CPU/execution time due to the context switching from userland to kernel when running the `gettimeofday()` system call.



The common pattern is:

<?php

$time = -microtime(true);

sleep(5);

$end = sprintf('%f', $time += microtime(true));

?>



Substituted as:

<?php

$start=hrtime(true); 

sleep(5); 

$end=hrtime(true);

$eta=$end-$start;



echo $eta/1e+6; //nanoseconds to milliseconds

//5000.362419



//OR simply



$eta=-hrtime(true);

sleep(5);

$eta+=hrtime(true);



echo $eta/1e+6; //nanoseconds to milliseconds

//5000.088229

?>



There is also the new StopWatch class http://php.net/manual/en/class.hrtime-stopwatch.php

php教程 php手册 php手册

hrtime

说明

参数

返回值

范例

参见

User Contributed Notes

php教程

php手册