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Apparently, as per Commit charge is 100% full but physical memory is just 60% when using no page file and http://brandonlive.com/2010/02/21/measuring-memory-usage-in-windows-7/, the Commit numbers in Windows 7 Windows Task Manager include both the physical and the swap memory, and count the virtual memory that has been allocated, but not necessarily has ever been used yet (i.e. not necessarily backed up by any physical source).

As such, is there a way to know the actual swap usage on the system? Simply subtracting physical memory from the Commit numbers won't work, as it apparently includes this unused-but-allocated space, too.

I mean, Windows 7 is supposedly a modern operating system; surely it must have the functionality to see how much of the swap space is actually presently being utilised, right?

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cnst
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1 Answers1

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The Performance Monitor (perfmon.exe) has counters for the page file usage.

  1. Load it up by either running "perfmon" on a command line, or by selecting "Performance Monitor" under Administrative Tools.
  2. Expand "Monitoring Tools" in the left column and select "Performance Monitor."
  3. Right-click on the graph to the right and select, "Add Counters."
  4. Scroll down the list of available counters to "Paging File."
  5. Click on the down-arrow icon to the right of "Paging File."
  6. Click on "% Usage" under "Paging File" and then click the "Add" button to put the counter under the "Added counters" list on the right.
  7. Click the "OK" button.

The graph will now contain a line for the page file utilization percentage.

Memitim
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    Sorry, forgot to add that you can also get numeric results and add to scripts by using PowerShell: `Get-Counter '\Paging File(*)\% Usage'` – Memitim May 21 '15 at 03:20
  • that seems a bit too complicated, especially considering that the upper limit is flexible and not set in stone. is there a way to get a number in GB or MB, instead of percentage points? also, is it the actual usage, or merely the commit minus the physical amount of DDR3? – cnst May 21 '15 at 03:23
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    Should be actual usage. "Should" because it is a black box check, so no way to verify the source, but it appears accurate in testing. As for getting a numeric quantity, either multiply the % usage by the page file size or get total page file usage of all processes in bytes: `get-counter '\Process(_total)\Page File Bytes'` – Memitim May 21 '15 at 03:35
  • Where do I input the code as you provide? Also, what kind of testing did you do -- did you try to allocate several gigs of RAM, to see Commit grow by said number (and exceed physical memory), but the Paging File counter remain the same? – cnst May 21 '15 at 03:40
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    You can either open a PowerShell command window and run the commands, or you can open a regular command window, type "powershell", and then type the command; i.e. `powershell 'get-counter '\Process(*)\Page File Bytes'`. You can also just type "powershell" by itself and hit enter to have the command window change to the PowerShell shell. – Memitim May 21 '15 at 03:55
  • As for testing, pretty much. Loaded up a few VMs to max memory usage and then loaded a couple more of known size. – Memitim May 21 '15 at 03:56
  • So, do you confirm these counters don't just relate to the Commit size? – cnst May 21 '15 at 04:03
  • @cnst: You can't "allocate RAM", at all. You allocate virtual address space. – Jamie Hanrahan Jul 17 '15 at 12:07
  • @cnst The `\Paging File(*)\% Usage` counter reflects the actual amount written to the pagefile, not the commit charge. But `\Process(*)\Page File Bytes` is the commit charge for the process, NOT that process's actual pagefile usage. In fact it is a duplicate of the Private Bytes counter (also the commit charge). (Yet another example of inconsistent and even misleading nomenclature in this area.) – Jamie Hanrahan Apr 18 '16 at 09:11
  • @JamieHanrahan, I completely lost track of the comments here, and the novelty of your last comment; if you think it's significant, and potentially answers the question in a better way, feel free to post it as a new answer instead! – cnst Apr 18 '16 at 16:59
  • @cnst The actual answer here is fine. (Perfmon's %usage counter shows actual pagefile usage, i.e. how much has been written to the pagefile. Yes, it shows it as a percentage of the pf's current size, but oh well.) However the Process\Page File Bytes counter shows a process' commit charge, which is more or less its maximum _potential_ pf usage. Since the original answer is correct, and commit charge is not part of the question, i don't think another answer would say anything different from this one. – Jamie Hanrahan Apr 18 '16 at 17:05