[SOLVED] Looping through WMI Query results very slow

[TheBrainiac]

I'm using WMI to poll my system's CPU load:

$objWMIService = ObjGet("winmgmts:\\localhost\root\CIMV2")

$cpu = 0

While 1
    $init = TimerInit()
    $colItems = $objWMIService.ExecQuery("SELECT LoadPercentage FROM Win32_Processor", "WQL", 0x30)
    For $objItem In $colItems
        $cpu = $objItem.LoadPercentage
    Next
    ConsoleWrite($cpu & "%" & @CRLF)
    ConsoleWrite(TimerDiff($init) & @CRLF)
WEnd

 

 

The For-loop in this example suspiciously always takes exactly one second (1008-1012ms) to finish, while not consuming large amounts of CPU time. Using debug lines, I have also confirmed that $colItems contains just one element. In fact it is For $objItem In $colItems​ that's taking this one second.

I understand there will be some conversion from the WMI return value to actual usable data, but it looks very much like there is either a delay or a timeout of some sort going on. Has anyone had similar issues? Have you found a way to get rid of it? If not, is there a similarly easy way to get CPU load without WMI?

Thanks for your feedback.

Edited May 17, 2015 by TheBrainiac

[mikell]

Seems to be a common issue as mentioned here
http://stackoverflow.com/questions/5465653/wmi-loadpercentage-call-is-very-slow
LoadPercentage : Load capacity of each processor, averaged to the last second. (msdn)

[TheBrainiac]

Ah, so it starts measuring CPU load and waits a second to get an average value. That explains the one second delay. Now this makes me wonder why it seemed to run fine in the past.

Thank you!