Last time I checked, Intel's MSRs (https://en.wikipedia.org/wiki/Model-specific_register https://en.wikipedia.org/wiki/Model-specific_register) allow Intel PCM

Last time I checked, Intel's MSRs (https://en.wikipedia.org/wiki/Model-specific_register https://en.wikipedia.org/wiki/Model-specific_register) allow Intel PCM (https://github.com/intel/pcm https://github.com/intel/pcm) to work, are indeed used to profile, or "measure performance" (sorry if my vocabulary is not the most accurate). Last time I checked the code of Intel PCM, it still relies on hardcoded values for each CPU which are as close as possible to reality but are still an estimation. It doesn't mean that you get wrong measurements, it means there's a level of inaccuracy that has to be accepted. BTW, I am aware that Intel PCM is not a profiler, and more of a measurement tool, however you CAN you use it to 'profile' your program and see how it behaves in terms of computing and memory utilization (with deep analysis of cache behavior (cache hit, cache miss, etc.))