RFR (XS): Enable UseCountedLoopSafepoints with Shenandoah

[Aleksey Shipilev]

On 12/20/2016 04:54 PM, Lennart Börjeson wrote:
>> 20 dec. 2016 kl. 16:26 skrev Aleksey Shipilev <shade at redhat.com>:
>> 
>> I am a bit confused about the notion of "standard behavior". There is no 
>> standard that mandates either putting safepoint checks into loops, or
>> skipping them.
>> 
>> This Shenandoah change _inserts_ more safepoint checks, not eliminates
>> them, so this seems like something you want?
>> 
> 
> I was thinking about the flag UseCountedLoopSafepoints. The current default
> is ”false”, and I gathered you were discussing to change this to ”true”?

Yes. "true" means Hotspot will emit safepoints checks in counted loops, thus
improving time-to-safepoint, and therefore improving pause time. Isn't that the
behavior you want for your product?

-Aleksey