Counting cycles and instructions on the Apple M1 processor
Recently, one of the readers of my blog (Duc Tri Nguyen) showed me how, inspired by code from Dougall Johnson. Dougall has been doing interesting research on Apple’s processors. As far as I can tell, it is entirely undocumented and could blow up your computer. Thankfully, to access the performance counters, you need administrative access (wheel group). In practice, it means that you could start your instrumented program in a shell using sudo so that your program has, itself, administrative privileges.
To illustrate the approach, I have posted a full C++ project which builds an instrumented benchmark. You need administrative access and an Apple M1 system. I assume you have installed the complete developer kit with command-line utilities provided by Apple.