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. (PHP 4, PHP 5) getrusage — Gets the current
resource usages $who= 0 ] ) This is an interface to
getrusage(2). It gets data returned from the system call. whois
1, getrusage will be called with Returns an associative array
containing the data returned from the system call. All entries
are accessible by using their documented field names. Example #1
getrusage() example $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)
Note: This function is not