RFR: Don't treat allocation regions implicitely live during traversal GC

[Roman Kennke]

Am 31.01.2018 um 21:03 schrieb Aleksey Shipilev:
> On 01/31/2018 08:59 PM, Roman Kennke wrote:
>> Until now, we treated allocation regions from between GC cycles all live in traversal GC. This seems
>> inconsequential: we are not treating alloc regions live during the cycle. This means that all the
>> allocated garbage will have to pass through one complete cycle to count its liveness, and then
>> another cycle to clear it up. This patch changes this to traverse+clear alloc regions in the next
>> cycle.
>>
>> This gives some application a huge boost. E.g. compiler.compiler goes from 180ops/m to around
>> 205ops/m in my tests.
>>
>> http://cr.openjdk.java.net/~rkennke/better-traversal-heuristics/webrev.00/
> 
> Um. Doesn't it break non-Traversal GCs? Shared/TLAB allocs would not be counted as live with e.g.
> "adaptive"?
> 

Grr. See this is what happens when you want to rush out a change when 
brain is pudding ;-) In my tests I guarded this by UseNewCode...

http://cr.openjdk.java.net/~rkennke/better-traversal-heuristics/webrev.01/

Better?

Roman