[philippta]

> I saw from the SSD was around 800 MB/s (which doesn’t really make sense as that should give execution speeds at 40+ seconds, but computers are magical so who knows what is going on).

If anyone knows what’s actually going on, please do tell.

[ricardo81]

Presumably after the first run much or all of the program is paged into OS memory

[tomtomtom777]

Yes, or it was still in memory from writing.

The numbers match quite nicely. 40gb program size minus 32gb RAM is 8gb, divided by 800mb/s makes 10 seconds.

[hellzbellz123]

I'm not entirely sure but could it be predictive branching?

[bmacho]

No, it needs to read the entire executable in order to be correct, it can't skip anything. Therefore the time for the IO must be a lower bound, predictive branching can't help that.