Using Resource Monitor to Troubleshoot Windows Performance Issues Part 1

Using Resource Monitor to Troubleshoot Windows Performance Issues Part 1

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Hello AskPerf! Leonard with the Performance Team here to discuss the Resource Monitor tool and we can use it to troubleshoot Windows Performance issues. In this blog, (the first of 2 on the subject of underutilized tools) I will discuss Resource Monitor which is available on both client and server versions of Windows starting with Windows Vista. Resource Monitor can be launched from the advanced tools tab in “Performance Information and Tools”, which is located in Control Panel. It can also be launched directly by running Resmon.exe.

Resource Monitor is a method of viewing Perfmon data. In fact, Resource Monitor is composed of Perfmon data combined with Windows Event Tracing data. You can view this tracing session by launching Perfmon, expanding Data Collector Sets, then select Event Tracing Sessions. There you will see a session called WDC.GUID (the GUID will vary). You can confirm this provides the data for Resource Monitor by observing that this trace is only running when Resource Monitor is running. Also, when it is running, you can view the channels that provide the data. Launching Resource Monitor will also launch a background process of Perfmon to act as a data source.

Resmon will show the window below on first launch. Each new launch will show the view as configured when Resmon was closed.

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There are 5 tabs to choose from. The overview tab gives a summary of the other ones. The main tabs are CPU, Memory, Disk and Networking. In each of the tabs the windows on the left can be collapsed, expanded and resized. It is also possible to filter each view by the process, for example you are only interested in seeing the activity for Explorer, check the box for that process and the bottom window will only show the activity for that process. With no processes selected, the bottom windows will show activity for all active processes. The graphs on the right can be resized between small, medium and large, but I would recommend keeping them at the default large setting. The numeric scale for the graphs will change as activity changes.

My Favorite features

The memory tab has one unique graph that provides a quick view of what physical memory is being used for.

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It is easy to see the total physical memory and what it is being actively used along with showing what is hardware reserved. Hardware Reserved represents physical memory addresses that have been reserved by hardware (generally busses like PCI or video cards) and is not available for Windows to use. It is usually small on x64 systems (except servers that do memory mirroring) but can be several 100MB up to 1GB on x32 systems. This means a 4GB x86 system can have only 3 GB of accessible memory.

The network tab is useful in that it not only shows the process that is generating activity, but the IP address it is connected to.

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I recently had an issue where the system process was showing high CPU activity on a Windows 2008 Server. Two of the things that run in system are the SMB and SMB2 processes. I suspected that the high CPU was due to network activity and was a load based problem and not a problem with a process. To confirm that was the cause, I used Process Explorer to determine the threads that were running in the system process. I confirmed that there were 15+ SMB and SMB2 threads that were always the highest consumer of CPU. I then ran Resmon and looked at all of the IP addresses that were associated with system. We identified a management server that was receiving a lot of data. Based on that information, we were able to narrow down the problem to the request coming from that server. While the problem could have been identified using different tools, Resmon provided the most efficient way to identify the problem.

I hope this overview of Resource Monitor will make it one of the tools you use the next time you need to look at performance data or activity on the system.

Additional Resource

-Leonard Severt

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  • This is such an informative article and very clearly written. Every single thought and idea is direct to the point. Perfectly laid out. Thank you for taking your time sharing this to you readers.

  • I wish every article was this useful.  Nice job.

  • I havent found any other better place on this blog to ask my question, so I hope it does not get forgotten here: is there a way to change the refresh interval (or otherwise said, refresh rate) of the resource monitor application? The only thing I can do is to either start or stop the monitor activity, but if its running, it refreshes the data approx. every 0.5 seconds, which is way to fast to read real-time data. A manual option to chooses between slow / fast refresh, similar to what we have since ages in task manager, would be really great. I mean if resource monitor does not have this kind of capability. Which I tend to believe, as there is no answer to this question on the entire internet.

  • Can I expect any reply to my question in the foreseable future?

  • Blake Morison / Leonard Severt: can I expect any meaningful feedback to my question here, or the comment section of this blog is purely for the amusement of your bored readers, and the staff never reads/reply them? Too bad there is no damn link on this blog where readers can contact the writers, and the publishers also hide their identity as much as possible. Blogs supposed to be interactive, and not write-once-forget-immediately.

  • @Richard Pasztor: Thanks for your feedback. Unfortunately, we have been extremely busy here in Support, so responding to Blog Comments take a back seat. We do have MVPs that reply to blog comments on a regular basis. As for your comment about contacting the writers, this will never happen, and I'm sure you can understand why. Thanks.

  • @Richard Pasztor: I just confirmed that resmon.exe is hard coded to 1 second intervals and cannot be changed. If you need higher intervals, then create a User Defined Data Collector set.

  • @Blake Morrison: thanks for the reply, at least I know this now (nowhere documented though). I wanted to have a LESS frequently refresh rate, as the 1-Hz rate is too quick for reading all the counters before another refresh overrides the values.

  • Does anyone know how to show storage on the disk tab that has not been assigned a drive letter? Is this an oversight?

  • I tried running Resmon.exe in Windows Server 2008, but it does not work!

  • Hi
    I am not able to see data on perfmon screen. I can see data on resmon.exe. Do I need to rebuild permon by LODCTR or something else? please help

  • @Akant: Check this KB: http://support.microsoft.com/kb/2554336

  • Do we have logs for whatever Resource Monitor captured?