RFR: 8007806: Need a Throwables performance counter

Alan Bateman Alan.Bateman at oracle.com
Mon Feb 25 09:59:26 UTC 2013

On 24/02/2013 20:57, David Holmes wrote:
> Does jstat access these values directly or only via the synchronized 
> methods? If the latter then the value can't be "torn" that way. The 
> sync method will store the value in 2 32-bit registers, and the 
> variable load in jstat will take two instructions, but nothing can 
> touch those registers.
The instrumentation/jvmstat buffer is a shared memory file so jstat 
(running in a different VM) just polls the counters so there isn't any 
Java-level synchronization.


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