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.
-Alan.
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