alt Hacker NewsWell, you can always pin to a core and move other threads out of that core.
That's what you'd do if manually scheduling. Ideally the dynamic scheduler would do that on its own.
Well, you can always pin to a core and move other threads out of that core.
That's what you'd do if manually scheduling. Ideally the dynamic scheduler would do that on its own.
Sure. But if you squint even that isn't good enough, you'll still take interrupts on that core in the critical section sometimes when somebody else wants the lock.
The other problem with spin-wait is that it overshoots, especially with an increasing backoff. Part of the overhead of sleeping is paid back by being woken up immediately.
When it's made to work, the backoff is often "overfit" in that very slight random differences in kernel scheduler behavior can cause huge apparent regressions.