Part 1 - Tools to Help Diagnose Performance Issues: ProcMon

In this series of short blog articles, I will discuss some freely available tools you can use to diagnose and resolve performance issues with your applications & servers.

In Part 1 of the series is a widely used and popular tool called ProcMon (also known as Process Monitor).

ProcMon can help diagnose some major performance problems very quickly and easily by listing (in real time) detailed file, network and registry activity on the screen per a particular process.

The best way to demonstrate the power of the utility is to show an example:

Example - Web Server IIS Logging

I was working on a project a while back actively performance testing Azure cloud web servers, using JMeter. During our tests we noticed transaction throughput drops and maxed out CPU utilisation on all of the web boxes.  After capturing a few minutes worth of ProcMon data, I immediately saw the problem to be the svchost process writing to a .log file in a folder with the prefix 'W3SVC' - from experience I know this to be IIS logging activity.

ProcMon - IIS Logging Activity

As you can see from the screen shot, there's a lot of read/write/open activity on the log directory. What you can't see is that almost all of the 62k events (bottom left figure) are associated with the IIS logging directory.

After turning IIS logging off on the server, the tests ran fine and utilisation was back down to normal levels.
Our client ended up filing a ticket to the Microsoft Azure team regarding the issue as this was not expected behaviour.

Another plus about ProcMon is that you can export the logs to a .PML format which gives you the full viewing ability later on (the above is a .PML extract which I then viewed on another machine). There is also the ability to export to .CSV however personally I found the .PML export a lot more useful (the .CSV export is a lot more limited in information provided).

Look out for the next part of the Performance Diagnosis Tools series! Follow the series by clicking on Twitter or subscribe to the Capacitas blog (on the right!) to get the latest info.