1. My profiling is rudimentary but effective. I measure per-kernel execution time with OpenCL events (which register with high accuracy start/end times w. practically no overhead), and also I continously measure per-iteration time by dividing wall-time for blocks of 20'000 iterations by that nb. These measuremens are consistent and sensitive.2. I'm not aware of good learning resources. Explore existing such code, e.g. opencl miners tend to use asm. Read in amdgpu/ in LLVM. Disassemble code from ...