Zig Profiling on Apple Silicon 12 months ago
In the M4, Apple mostly added counters only for the SME engine. The full list of supported counters can be found in the official guide: https://developer.apple.com/documentation/apple-silicon/cpu-...
Regarding branch profiling, all arm64 (M1+) cpus support these counters: - BRANCH_CALL_INDIR_MISPRED_NONSPEC - BRANCH_COND_MISPRED_NONSPEC - BRANCH_INDIR_MISPRED_NONSPEC - BRANCH_MISPRED_NONSPEC - BRANCH_RET_INDIR_MISPRED_NONSPEC - INST_BRANCH - INST_BRANCH_CALL - INST_BRANCH_COND - INST_BRANCH_INDIR - INST_BRANCH_RET - INST_BRANCH_TAKEN
afaik there is no limitation to implementing the fetching of all these counters based on ibireme’s research on kperf. btw, forked "poop" already can fetch BRANCH_MISPRED_NONSPEC.