Performance Counters Timeouts and Load Testing with Visual Studio

If you are getting following error while running load test and wondering why this happens. Here in this blog entry I highlight ways to fix it.

The performance counter category ‘Memory’ cannot be accessed on computer ‘COMPUTER01’ (Timed out trying to read performance counter category ‘Memory’ on computer ‘COMPUTER01’); check that the category and computer names are correct.

Performance Monitor Tool (perfmon)

This is a well known Windows in-build tool for fetching performance data. First try to fetch the required performance counter from specific machine through this tool. You may notice two things here if your machine is a remote machine. If it takes more time (more than 1/2 minutes) to get the performance counters, that will indicate that you need to change timout values for load test configuration. OR if it does not access the counter then there are permissions issue.

Performance Monitor User Permissions

If you are not able to access performance data from perfmon, then you have to correct that first. As same permission level applies to visual studio load test when it tries to fetch performance data. User who is trying to access performance data (locally/remotely) should be part of  ”Performance Monitor Users” and “Performance Log Users”. If there are not much security concerns make the user part of Local “Administrators” group which will ensure full access on the machine.

Sometimes still there may be some issues. In that case just remove the User or the Group of which the User is part of, from “Users” Group of target machine. Which will provide you fully un-restricted access to machine.

Firewall Exceptions

Rarely you may have to do it. Either turn off the local firewall or enable the rules for Performance Logs and Alerts in the Windows Firewall with Advanced Security snap-in.

Load test timeout settings

If permission levels are all fine. But still you are still running into the same issue. That means you have to set load test’s performance counter initialization time out settings. But where to do that? as there is no provision to do it though VS IDE. For that you have to do some manual configurations in load test’s hosting process’s configuration file. Now this configuration file is different for VS 2008 and VS 2010. Following are the details on that.

For Visual Studio 2008, open the file VSTestHost.exe.config in the folder C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE

OR

For Visual Studio 2010, open the file Devenv.exe.config in the folder C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE

AND then add following entries to it. That will solve the timout issue.

<appSettings> 
     <add key=”LoadTestCounterCategoryReadTimeout” value=”60000″/> 
     <add key=”LoadTestCounterCategoryExistsTimeout” value=”60000″/> 
</appSettings>