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Get-Counter failing with error : A counter with a negative denominator value was detected

Answered Get-Counter failing with error : A counter with a negative denominator value was detected

  • Wednesday, February 29, 2012 6:09 PM
     
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    Hi Folks,

    I have a weird situation where I am sampling the CPU usage for small duration and taking an average of the usage using the 'Get-Counter' command. This command seems to work well when tried directly in the powershell prompt. However, when we use the same command in script, the following error throws up, 

    Starting process to consume CPU cycles
Get-Counter : A counter with a negative denominator value was detected.
At C:\Monitor.ps1:100 char:29
+         $sys_cpu_obj = Get-Counter <<<<  '\Processor(_Total)\% Processor Time'
    + CategoryInfo          : InvalidResult: (:) [Get-Counter], Exception
    + FullyQualifiedErrorId : CounterApiError,Microsoft.PowerShell.Commands.GetCounterCommand

PS C:\> Get-Counter '\Processor(_Total)\% Processor Time'

Timestamp                 CounterSamples
---------                 --------------
2/29/2012 9:56:47 AM      \\vms1\processor(_total)\% processor time :
                          26.2817087701422




PS C:\>

    Here is the routine that is being executed, 

    function sample-CPUUsage([int] $iterations=3,[int] $sampling_interval=2){
	[long] $sum=0
	# Collect an average of physical memory usage
	for($i=0; $i -lt $iterations; $i++){
		$sys_cpu_obj = Get-Counter '\Processor(_Total)\% Processor Time'
		[long] $cpu_usage=$($sys_cpu_obj.CounterSamples).CookedValue
		$sum+=$cpu_usage
		Start-Sleep -Seconds $sampling_interval
	}
	[long] $sum=[long] ($sum/$iterations) 
	return $sum 
}

    Why am I getting this error when running the same command from the script ?

    -Pranav

     

All Replies

  • Wednesday, February 29, 2012 6:15 PM
     
     
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    Your function seems to work on my machine.

    Grant Ward, a.k.a. Bigteddy

    What's new in Powershell 3.0 (Technet Wiki)

     
  • Wednesday, February 29, 2012 7:27 PM
     
     
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    This error might be a bug with powershell. It doesn't always shows up. I am not sure what to do with this...

    -Pranav

     
  • Thursday, March 01, 2012 5:36 AM
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    Hi,

    I cannot reproduce your issue either. It seems like that this issue a issue related with your environment.

    Based on the error message "A counter with a negative denominator value was detected", it seems like that $iterations sometimes is treated as a negative number. How about change [long] $sum=[long] ($sum/$iterations)
     as

    [long] $sum=[system.math]::abs([long] ($sum/$iterations))

    Best Regards,

    Yan Li 

    Yan Li

    TechNet Community Support