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copied!<p>I've had CPU spikes when listening to WMI events in cases where I have failed to detach properly from my events on exit/cleanup. You might want to check you are not "leaking" WMI event subscriptions. Just in case detach from the event as early as possible and make sure you always do it.</p> <p>To illustrate further, here's an example from <a href="http://rads.stackoverflow.com/amzn/click/1590599403" rel="nofollow noreferrer">my PowerShell book</a> that listens to WMI events using the PSEventing library:</p> <blockquote> <p>Add-PSSnapin PSEventing -ErrorAction SilentlyContinue</p> <p>$queryString = @' SELECT * FROM __InstanceModificationEvent WITHIN 10 WHERE TargetInstance ISA 'Win32_Service' AND TargetInstance.Name = 'w3svc' AND TargetInstance.State = 'Stopped' '@</p> <p>$query = New-Object System.Management.WQLEventQuery ` -argumentList $queryString </p> <p>$watcher = New-Object System.Management.ManagementEventWatcher($query)</p> <p>Connect-EventListener watcher EventArrived </p> <p>$watcher.Start()</p> <p>echo "Waiting for the W3CSVC service to stop..." Get-Event -wait | <code> foreach {</code> Write-Host -foreground Red "The W3SVC service has stopped!" }</p> <p>$watcher.Stop() </p> <p>Disconnect-EventListener watcher EventArrived</p> <p>echo "done"</p> </blockquote> <p>If I do not do the <strong>Disconnect-EventListener</strong> bit upon script exit, I get CPU spikes the third or fourth time I attach to the event. My guess is that the system still tries to deliver events.</p>

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