As an extra footnote to the CPU Slowdown post about Akai Katana, here’s two more fun pictures, showing other stuff that can happens.
First, there are actually some rare occasions where Blitter induced slowdown can matter. This happens very rarely in Akai Katana, but sometimes when there’s a lot of draws going on, the Blitter processing takes more than a frame, and we can see the CPU repeatedly doing ready checks by pulsing CS6.
As mentioned earlier, this is very infrequent in this game, and almost all slowdown is just CPU being slow.
The other fun thing is that the CPU often does enough work that it doesn’t even have time to process it in two frames, which means several frames of slowdown. The example below shows CPU processing and waits causing two extra frames of slowdown, but more can happen too.
It really feels like this was rushed out without much thought given to performance.