RFR 8006007: j.u.c.atomic classes should use intrinsic getAndXXX provided by 7023898

Chris Hegarty chris.hegarty at oracle.com
Thu Jan 10 17:15:47 UTC 2013

On 01/10/2013 05:05 PM, Aleksey Shipilev wrote:
> On 01/10/2013 08:40 PM, Chris Hegarty wrote:
>> Doug, Aleksey,
>> I updated the appropriate methods in the Atomic classes to use the
>> instinsics defined by 7023898 , Unsafe getAndAddInt, getAndSetInt,
>> getAndAddLong, getAndSetLong, getAndSetObject.
>> http://cr.openjdk.java.net/~chegar/8006007/webrev.00/webrev/
> Good. Two comments:
>   a) Any java-concurrency-torture [1] failures for these classes?

Can you give me a brief introduction to running these? I have run the 
JDK regression tests and the appropriate JCK tests, all pass.

>   b) Can we delegate all the suitable methods to Unsafe directly, without
> calling the middleman (i.e. getAndDec() -> getAndAdd() -> unsafe), as in
> [2]?

Yes, we could. The existing implementation was not consistent.

I took the view that this was not performance critical, since some 
existing methods already delegate, and my preference, for simplicity, is 
for the middleman ;-) Do you think there is a perf benefit to changing 
this, or is this a style issue?


> -Aleksey.
> [1] https://github.com/shipilev/java-concurrency-torture/
> [2]
> https://github.com/shipilev/java-concurrency-torture/blob/master/src/main/java/org/openjdk/util/concurrent/atomic/AtomicIntegerV8.java

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