Request for reviews (S): 7071709: JSR 292: switchpoint invalidation should be pushed not pulled

[Christian Thalinger]

On Aug 26, 2011, at 1:47 AM, John Rose wrote:

> On Aug 25, 2011, at 11:32 AM, Tom Rodriguez wrote:
> 
>> The docs for VolatileCallSite suggest setTarget can be called whenever you feel like it, so it seems like it can be set many times.  MutableCallSite can be as well but the implication is that it's not updated very often.  I'm actually unclear what distinction is trying to be made with VolatileCallSite.
> 
> The MCS and VCS have the same semantics, except for the extra memory barriers on VCS.  These barriers do not affect the validity or applicability of push notification.  Also, either an MCS or VCS might end up being "megamutable", so there has to be some sort of cutoff that will prevent target-prediction for a CS which has been mispredicted too many times.  We need to squeeze a bit of state into the CS, somewhere, which displays how many times the thing has been mispredicted.

So the question is should we go with what we currently have for invokedynamic (only optimize CCS and MCS) or should we allow all CSs to be optimized and start working on the logic John describes.  I'm fine with both.

-- Christian

> 
> -- Joh

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