1Future ABI changes 2================== 3 4This file collects items that require a libperf ABI bump. Each entry 5should describe the current limitation, the desired end state, and the 6scope of the change so that a future ABI revision can batch them 7together. 8 91. Widen struct perf_cpu.cpu from int16_t to int 10 - Current limit: 32767 CPUs. No architecture exceeds this today 11 (x86_64 max is 8192, arm64 is 4096), but NR_CPUS limits keep 12 growing. perf clamps to INT16_MAX in set_max_cpu_num() as a 13 safety net. 14 - Scope: struct perf_cpu is embedded everywhere — perf_cpu_map__cpu(), 15 perf_cpu_map__min(), perf_cpu_map__max(), perf_cpu_map__has(), the 16 for_each_cpu macros, and all internal callers. The perf_cpu_map 17 internal array (RC_CHK_ACCESS(map)->map[]) stores struct perf_cpu 18 directly. Widening changes the struct layout and every function 19 that returns or accepts struct perf_cpu by value. 20 - Migration: bump LIBPERF version in libperf.map, audit all 21 sizeof(struct perf_cpu) assumptions, update perf.data 22 serialization if needed. 23