RFR (M): Rehash barrier disable flags, add Shenandoah{CAS,Acmp,Clone}Barrier flags

[Aleksey Shipilev]

Forgot to handle SATB pre-barrier. Also store-val barriers should be handled by
ShenandoahWB, not RB. Fixed both:
  http://cr.openjdk.java.net/~shade/shenandoah/barrier-disable/webrev.02/

Tests still pass.

Thanks,
-Aleksey

On 02/20/2017 03:25 PM, Roman Kennke wrote:
> Yes! Great!
> 
> 
> Am 20.02.2017 um 15:12 schrieb Aleksey Shipilev:
>> Hi,
>>
>> Running with "passive" heuristics that frees us from requiring the operational
>> runtime barriers, and -XX:Shenandoah{Read,Write}Barriers are useful to dissect
>> runtime performance. However, those are handled inconsistently in the code, and
>> also we miss other three flavors of barriers: CAS, acmp, and clone barriers.'
>>
>> This change rehashes the handling for these barrier disable flags:
>>   http://cr.openjdk.java.net/~shade/shenandoah/barrier-disable/webrev.01/
>>
>> Disabling all barriers brings runtime performance very close to ParallelGC,
>> which seems to validate the approach.
>>
>> Testing: hotspot_gc_shenandoah (x86), eyeballing assembly (x86), targeted
>> benchmarks (x86).
>>
>> Thanks,
>> -Aleksey
>>
> 
>