RFR: 8187042: Events to show which objects are associated with biased object revocations

[David Holmes]

Hi Robin,

On 6/10/2017 8:22 PM, Robin Westberg wrote:
> Hi all,
> 
> Please review this change to add event-based tracing events for biased 
> lock revocations:
> 
> Issue: https://bugs.openjdk.java.net/browse/JDK-8187042
> Webrev (courtesy of Erik Gahlin): 
> http://cr.openjdk.java.net/~egahlin/8187042/

I have a few queries:

First, why is there no event for the self-revocation path?

Second, is there a reason you can't put the event management inside the 
VM operation code and so avoid the need to adjust the safepoint counter?

Third, I would have expected to see more detail in the event such as 
which thread (id) the object was biased to and which thread revoked the 
bias. Even perhaps some notion of which instance was involved (though 
that's harder to shows).

Thanks,
David

> Best regards,
> Robin