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Is there any easy way on Windows to log %CPU time per process over time to a file for later analysis?

As far as I can see...

  1. Task manager shows me the %CPU per process but only visually - no way to save to a file.
  2. Perfmon will let me save to a file, and will additionally create a time-based file (taking snapshots at specified time intervals) - which is almost what I want, except that as far as I can see it can't break down the %CPU by process.
  3. Process Explorer will let me break down by process, but it will only save the file as a snapshot of a single point in time

So, none of these are quite what I need: I need to get a file that contains something like 'top 10 processes by CPU, every 15 seconds, until I stop the monitoring' The reason I need this because I have a machine on which some process is causing occasional brief spikes in CPU usage several times a day and I need to find out which process is the culprit.

Can anything do that, or have I missed some feature of perfmon or process explorer?

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Process Monitor can do that for you.

You'll first might want to enable collection of profiling events:

enter image description hereenter image description here

Then, simply collect data for as long as you want (you may want to set up filters and enable Drop filtered events if you plan to collect for extended periods of time). Then go to Tools -> Process Activity Summary:

enter image description here

You'll now get a list of all active processes you recorded, with their activity over time. enter image description here

You can then open the details for a single process (by double-clicking on it) and inspect the timestamps for certain events in the graph:

enter image description here

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Thanks. That's visually quite impressive (I dread to think how much memory it uses if you leave it running for a long time). It certainly is useful for being able to see on the screen what processes were doing. However, if I click 'Save' from the process activity summary screen, what is saved is still a single-point-in-time snapshot, no time-dependent data. –  PhantomDrummer Jul 26 '12 at 14:55
    
@PhantomDrummer: Saving and loading PML files works excellently for me. All previously recorded events are restored and available for analysis after loading a PML. Make sure to select All events when saving the file. In case it just doesn't want to work, let me know and I'll include more details in my answer. Good luck :) –  Oliver Salzburg Jul 26 '12 at 15:00
    
Thanks Oliver, I've managed to get the process profiling to work. The points I'd missed were that you need to enable profile events via the filter. Then from the main window I can save the events to csv. –  PhantomDrummer Jul 27 '12 at 7:48
    
One follow-up: Is it possible to change the frequency with which process monitor collects profiling events? We only really need about every 15 seconds, from what I can see of the results it's collecting at least every second, and I'm worried that'd going to eat up too much memory/filesize since we'll need to leave it running for a day or two. –  PhantomDrummer Jul 27 '12 at 8:04
    
@PhantomDrummer: Go to Options -> Profiling Events. There you can set the interval to either 1s or 100ms. That's as far as it goes. If the file still grows too big, you must set up more strict filters and enable Drop Filtered Events. –  Oliver Salzburg Jul 27 '12 at 9:24
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