Cpu Utilization in vb6

[Joacim Andersson]

Moved to the VB6 CodeBank.

When compared against Task Manager, the average values are oftentimes in disagreement. In fact, negative percentages are sometimes displayed. BTW, CpuTime was implicitly declared as a Variant.

That's because the code is completely wrong. What it tries to do is to get the CPU usage information from each running process, but it updates the information inside the loop.

Say you have 96 running processes (which is what I currently have with all services and apps that runs) then the For Each loop will loop 96 times, but it updates the textbox inside the loop and the only one you will see is the last one, where the PrevCpuTime is set to .... well, who knows? It will be something like the KernelModeTime used by the earlier process, which is not even of interest.

To get the CPU usage you shouldn't go through the running processes, instead you should get the processor information (as opposed to process information), since modern day computers have more processor cores you have to add them up and then to get an average divide the result with the number of processors in your computer (this isn't perfect since you get an average, but it's close enough).

Private wmi As Object

Private Sub Form_Load()
    Me.Show
    Set wmi = GetObject("winmgmts:\\.\root\CIMV2")
    Timer1.Interval = 1000
    Timer1_Timer
End Sub


Private Sub Timer1_Timer()
    Dim query As Object, counter As Object
    Dim percent As Double
    Set query = wmi.ExecQuery("SELECT * FROM Win32_PerfFormattedData_Counters_ProcessorInformation")
    For Each counter In query
        percent = percent + counter.PercentProcessorTime
    Next
    Text1.Text = Format(percent / query.Count, "0.00") & "%"
End Sub