On 12/06/12 06:56, Vitaly Davidovich wrote:
Doug,
When you see the fast to slow ThreadLocal transition due to class loading
invalidating inlined get(), do you not then see it get restored back to fast
mode since the receiver type in your call sites is still the monomorphic
ThreadLocal (and not the unrelated subclasses)? Just trying to understand what
Rémi and you are saying.
The possible outcomes are fairly non-deterministic, depending
on hotspot's mood about recompiles, tiered-compile interactions,
method size, Amddahl's law interactions, phase of moon, etc.
(In j.u.c, we have learned that our users appreciate things
being predictably fast enough rather than being
unpredictably sometimes even faster but often slower.
So when we see such cases, as with ThreadLocal, they get added
to todo list.)
-Doug
