RFR: Re-enable Thread-local handshakes by default in Shenandoah

[Roman Kennke]

Am 26.06.2018 um 09:53 schrieb Aleksey Shipilev:
> On 06/25/2018 06:00 PM, Aleksey Shipilev wrote:
>> On 06/25/2018 05:54 PM, Roman Kennke wrote:
>>> Back in February we disabled TLHS because it caused compilation
>>> failures. I tried today, and it doesn't seem to cause problems. I
>>> propose to re-enable it and stay with defaults, unless we encounter
>>> problems again.
>>>
>>> Testing: tier3_gc_shenandoah, some specjvm
>>>
>>> Ok?
>>
>> OK.
> 
> Well, this makes Serial hang with -XX:+UseShenandoahGC -Xmx4g -XX:+UnlockExperimentalVMOptions
> -XX:ShenandoahGCHeuristics=traversal. The hang goes away with -XX:-ThreadLocalHandshakes. Please
> reinstate the fix back?
> 

Too bad. I pushed a backout changeset.

Thanks for testing!
Roman