PPU LLVM JIT Repository Early Testing

[ssshadow]

?

This is some strange bug with the emulator. I can get really good speed, like 70 fps on the opening video for some very short or very long period of time, but eventually frame rate just drops to nothing, like 6 fps right now. This happens at the same time as rpcs3.exe frees like 1 gb (!) of memory too for whatever reason.

But whatever, this is a WIP.

EDIT: Performance can go both ways, TGFP went from 25 -> 70 fps while cpu usage went from 60 % -> 40 %. A wild and uneducated guess would be cache misses, branch prediction doing the wrong predictions, or similar. CPU clock was consistently 2,8 ghz.

The algorithm the JIT recompiler uses to detect which basic blocks of code need to be compiled is very simplistic and inefficient and results in the same basic block being compiled more than once. Ideally each block must be recompiled only once. This has the following negative effects:

1. The recompiler ends up using a lot of memory
2. It takes more time than what is ideally required to recompile a section of the code.
3. It produces a lot of code which can cause caches to overflow.

I am working on a more intelligent algorithm which should hopefully fix the issues that you are seeing.

OK, that is a good explanation, thank you.