Comment by gonzo

14 hours ago

“Hyperthreading” is a write pipe hack.

If the core stalls on a write then the other thread gets run.

It's much more than that. It also allows one thread to make progress while the other is waiting for memory loads, or filling in instruction slots while the other thread is recovering from a branch mispredict.

Compilers tend to do a lot of pointer chasing and branching, so it's expected that they would benefit decently from hyperthreading.