Limit the execution time of a process tree on Windows


I was recently looking for a tool which would allow me to limit the total execution time of a process and its children. I haven’t found anything, so I decided to implement such a feature in Process Governor, my open-source process-monitoring application. You may download the v2.3 version from GitHub. In this post, I want to present you the new functionality and describe its implementation details.

When we know the PIDs of our running processes, we could use a simple command to wait for the processes to finish (the Wait-Process cmdlet is an ideal example) and kill the remaining ones if they pass the limit. However, what if we only know the PID of the initial process? Tracking processes hierarchy in a script could become problematic. A simple and clear solution would be to assign a job object to the initial process, let it create new processes, wait the specified period and terminate the job if any of the processes is still running (terminating the job exits all the processes). There are, however, few questions we need to answer:

  • How do we know all processes associated with the job finished their execution?
  • What types of process execution time should we measure?

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Releasing wtrace 1.0 and procgov 2.0


In today’s short post I would like to present you a new tool in my diagnostics toolkit: wtrace, and an update to procgov (or Process Governor). Let’s start with wtrace.

wtrace

On Linux, when I need to check what a given process is doing, I usually use strace. I was always missing such a tool for Windows. We have procmon (which is great), but it does not run in a console, and thus can’t be used in the command line scripts, or on a Nano server. This might change soon, as in one of the latest episodes of the Defrag Tools show, Mark Russinovich shared the plan of releasing the procmon version for Nano. Till then though we don’t have much choice when it comes to real-time tracing. You may think of xperf or wpr, but those tools only record ETW events for further analysis. However, we may use the same ETW events in a realtime session, and print information they provide to the console output. This is how the idea for wtrace was born in my head. Few weeks ago Sasha Goldshtein released another tool for ETW processing named etrace, which basically does something very similar and has many interesting options. I decided to publish wtrace nonetheless, as my point was to create a tool with an extremely simple interface. Wtrace is collecting only a small subset of events (FileIO, TcpIp, Process/Thread Start) from the kernel provider. It may either start a process, or trace one that is already running. At the end of the trace it also shows some statistics (unless you use the –nosummary switch). Trace session will end either when you press Ctrl+C, or when the traced process terminates. Events are printed in the console window. An example session might look as follows:

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Set process memory limit with Process Governor


Today I would like to introduce you to Process Governor – a new tool in my .NET diagnostics toolkit. This application allows you to set a limit on a memory committed by a process. On Windows committed memory is actually all private memory that the process uses. I wrote this tool to test my .NET applications (including web applications) for memory leaks. With it I can check if under heavy load they won’t throw OutOfMemoryException.

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