How to measure VAS with FSUIPC


measuring-vas-fsuipc2.pngYou can measure the status of the VAS using FSUIPC and place the measurement on screen.

If you don’t know what VAS is, please read first this post :: How Memory is Managed by the OS.
Further you can read all about Memory issues in this category.

With FSUIPC you can measure the Available FS memory (as it is called in the FSUIPC Offset Status.pdf). With the offset code 024C with Type S32 you measure the Available Virtual Address Space in kilobytes. This value is updated every 10 seconds.

The Available VAS + the Virtual Size of the process Prepar3D.exe equals ± 4GB as being the total VAS space for each 32 bits process. With other words: the  4GB VAS space minus the virtual size of the process Prepar3D.exe equals the remaining available virtual address space. When this VAS space is consumed…you get an OOM error message.vas-maxed-out2.png

How to show Available VAS on screen.

  1. In Prepar3D open Add-ons – FSUIPC and select tab Logging.
  2. Check: IPC reads  in Log Details and FS Window (or FS Title Bar) in Display to
  3. Fill Offset = 024C and Type =32 in the Specific value checks
  4. Close with OK
  5. You can drag and resize the green FS Window bar as desired to any convenient place on the screen. Once configured in FSUIPC it will appear again at next start.

measuring-vas-fsuipc.pngYou could also place the information in the FS Title Bar for a better reading result.

The value in the Title bar is read as 2643028 x KB=2.643 MB …as we speak of 2.6 GB.vas-maxed out3.PNG