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I always (subjectively) feel my computer is far too slow (however fast it is), and so I'm always looking for ways to measure and understand what my computer is actually doing, that is making it seem "slow" to me. It has been my observation that my software-developer workload is most often disk-bound (I am waiting for Disk I/O) more than CPU bound. What has made it worse, is that I am using a corporate PC that has in-memory active-scanning anti-virus software that I do not have control over, and also some IT department mandated services that seem to suck up a lot of available hard-disk bandwidth.

The best tool I have seen (in Windows 7) is the Resource Monitor which I usually acess from the button in the task Manager. The disk IO page, however, seems to label Disk Activity at a very low level (for example, showing the Volume Shadow Storage, which is flushing information obviously written by something ELSE other than VSS itself, and then writes to Pagefile.sys, which are obviously due to Virtual Memory faults in some application).

What I would like to know is if a utility exists that can add up all direct disk input and output by user-level process, or find the process or service that caused VM or VSS activity. In that way, I hope, you could establish a real idea of how much of your computer's precious disk subsystem bandwidth is attributable to a particular application.

here's a scenario:

  1. MyApp.exe writes 100k/s and reads 100k/s directly.
  2. VSS ends up writing another 100k/s.
  3. pagefaults caused inside MyApp.exe cause another 100k/s of writes.

So the total "cost" of MyApp.exe running, during a period of time (let's say 1 second) is 400k/s, whereas you can only directly observe half of that, in Resource Monitor.

Is there a smarter disk-IO watching piece of software I can use?

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up vote 1 down vote accepted

Check out the Sysinternals suite. It has several tools that will help you, including one called ProcMon which will show you everything disk related.

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ProcMon is good, and if it would do more than just dump everything in a big long list (120K events per minute or more), I could use that info. What I actually want is to know the total numeric amount of disk activity, collated by process id. – Warren P Feb 9 '11 at 16:51
File Summary page in ProcMon is brilliant! Just what I needed. – Warren P Feb 9 '11 at 16:51

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