the usual C2 kicks-in is 10000, not 5k. But that statement about warming up is true only for microbenchmarks.

C1 which is an dumb (but not terrible) compiler tends to be at 1k, and if you cannot get your code to 1k, likely it never needs compilation, so no point to spend time and space on performing the said compilation.

The 'prewarming' does include perf. counters, so it's guided compilation to boot.