Unfortunately, I haven’t had much time to work on paraLLEl lately, but there is plenty to update about.
paraLLEl RSP – Clang/LLVM RSP recompiler experiment
Looking at CPU profiles, paraLLEl RDP could never really shine, as it was being held back by the CXD4 RSP interpreter, so groundbreaking speedups could not be achieved. With paraLLEl RDP, the RSP was consuming well over 50% CPU time. This was known from the beginning before RDP work even started. After the first RDP pre-alpha release, focus shifted to RSP performance, and that’s what I’ve spent most time on. None of my machines are super-clocked modern i7s, which have been required to run N64 LLE at good speed.
Micro-optimizing the interpreter is a waste of time, I needed a dynarec. However, I have never written a dynarec or JITer for that matter before, and I was not going to spend months (years?) learning how to JIT code well for ~4 architectures (x86, x64, ARMv7, ARMv8). Instead, using libclang/libllvm as my codegen proved to be an interesting hack that worked surprisingly well in practice for this project.