Add CPU cycles load (CPU user and system time) measurement to report

[MurzNN]

Not only memory and time are give performance problems, very often CPU usage is also the problem. But now we don't measure it.
Will be good to add measurement of CPU usage time too!
In PHP we can easily get them via this code:

$rUsage = getrusage();
$cpuTimeUser = $rUsage["ru_utime.tv_usec"]; // user time used (microseconds)
$cpuTimeSystem = $rUsage["ru_stime.tv_usec"]; // system time used (microseconds)

Also there are many other metrics that can be useful, so maybe store full result of that function, instead of several values, and allow to manually add needed ones to report?