Plugin Performance

The Performance popup displays all loaded python plugins, with the “All” line showing the performance for all of XPPython3 plugin itself (sum of the plugins plus overhead). The columns show time spent (in microseconds μ) per frame, divided into categories:

You can compare these values with those provided by X-Plane’s built-in Plugin Admin Performance tab:

The Flight Loop column in the popup will very closely match the “Flight Loop” line in the X-Plane performance tab. (Though it doesn’t happen to in the images here.) This is the time spent executing a flight loop callback. For XPPython3 performance, we’ve been able to determine which python plugin is using the most time. (Note the performance presentation itself is done within the I_PI_Updater plugin, which is why it’s consuming 146 μsec per frame: if you’re not displaying the performance window, the flight loop is canceled.)

The Drawing Misc column also closely matches the “Drawing Misc” line in the performance tab. This covers work done within drawing callback, usually associated with windows you’ve created.

Custom Widgets reflect time spent working with custom widgets. Usually the largest amount of time is spent drawing custom widgets, so if none are displayed, this number will be very small. This figure does not include time drawing non-custom widgets. I don’t have access to that time. X-Plane’s “Drawing Window” value appears to include all widget work, including drawing non-custom widgets (which we don’t include).

Finally, the Percentage column shows how much of XPPython3’s time is allocated to a particular plugin. In the above example, you can see the PI_SeeAndAvoid plugin is responsible for about 61% of XPPython3’s time, a majority of that is due to “Drawing Misc”. Indeed, SeeAndAvoid has an on-screen “Flight Following” window which constantly updates based on the location of nearly aircraft: If you choose to not display Flight Following, the plugin’s “Drawing Misc” value drops to near zero.

At the bottom of the popup is the current sim frame rate, expressed in microseconds and in FPS (which is simply 1 / frame rate). Also displayed is the approximate impact of XPPython on the frame rate. As in the above example, we know XPPython3 is spending 367 μsec during each flight loop. Because the current sim time is able to execute a frame in 19370 μsec, if we were to remove python, we’d expect the sim frame to be about .98 FPS faster.

(Note that doesn’t mean python “costs” 0.98 FPS in every scenario – if you were flying in NYC with heavy weather, X-Plane may be running 20 FPS, or one frame per 50000 μsec: XPPython flight loop would still only take 367 μsec (because it’s doing exactly the same work as before). Removing python would allow the sim frame rate to speed up from 50000 μsec/frame to 49633 μsec/frame for an increase FPS by less than 0.15 FPS).

In any case, I hope this is helpful: If you’re developing python plugins, this can give you some insight into how they’re performing. If you’re wondering what’s slowing down your system, this might help you determine the bottleneck. XPPython3, by itself, consumes very little time.