Realtime performance profiling

Summary

So during the development of our project 7 for TGA we encountered an issue, Performance.
Just randomly picking out things to optimize is guaranteed to result in sub-optimal usage of our time, we needed to know where, or atleast close in where the bottlenecks could be.

These were my goals

Find out why the performance is less than acceptable.
Simplify the effort needed for this in the future.

The solution

A simple stopwatch or timekeeper to sort through all the data, simply applying a start/stop at every system or part of a larger class.
The interface would look something like this.

With a little bit of usage like this.
RM::TimeKeeper::Start(“Waiting for GPU”);
myGraphicsEngine->EndFrame();
RM::TimeKeeper::Stop();

With a StartFrame and EndFrame at the start/end of a frame, the StartFrame and EndFrame are there to sync across thread_local variables for multi-threading support… It’s a real shame I have not had the time to multi-thread the main-loop of RiktigMotor.

Calling display shows this ImGui window, with the following statistics for the first level in our game. These results are part of why I have not yet multi-threaded the engine, if you’re still Waiting for the GPU, the frame-rate is not going to increase, regardless of how many threads you can split the work on, you’re still going to wait for the GPU.

We already have some on/offs for all(almost) major parts of the engine, using that it did not need a lot of effort to test what system used all the GPU. Spoiler, it was mostly the point lights. But that’s fixed now. Finally here’s an image of our DebugTools to show how we turn systems on/off in real-time.

Conclusion

It’s as important to know where to improve as it is to know how. Take your time to figure out where the bottlenecks are, a little research can save you hours of trial and error. Here’s a link to the source code, beware it’s not been cleaned, I just took it straight from the codebase after reading it through to see I don’t give out anyone elses code.

TimerKeeper on github