We don't need to estimate the hit Frequency which could be time-varying.
If we can use a 2 counters, we can precisely determine the 1,000,000th hit. One slow-counter one regular fast counter. But that means we use 32 bits for our counters, like a 32-bit counter!
void increment(){ // was named count()?
static int count16bit;
long unsigned int now = system_time_in_nanos();
if (now%16 == 0){ //just check last 4 bits of "now"
count16bit++;
//now check count16bit
if (count16bit <= 0){cout<<"got it"<<endl; }
}
}
https://en.wikipedia.org/wiki/Approximate_counting_algorithm#Algorithm is the standard implementation of a similar idea.
