RFR: Compact heuristics should not shortcut on immediate garbage, but aggressively compact

[Roman Kennke]

Am 28.03.2018 um 19:59 schrieb Aleksey Shipilev:
> Spotted a little inefficiency in our "compact" heuristics:
> 
> diff -r cb0e69eec083 src/hotspot/share/gc/shenandoah/shenandoahCollectorPolicy.cpp
> --- a/src/hotspot/share/gc/shenandoah/shenandoahCollectorPolicy.cpp	Wed Mar 28 19:54:45 2018 +0200
> +++ b/src/hotspot/share/gc/shenandoah/shenandoahCollectorPolicy.cpp	Wed Mar 28 19:58:52 2018 +0200
> @@ -600,6 +600,7 @@
>    ShenandoahCompactHeuristics() : ShenandoahHeuristics() {
>      SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahUncommit);
>      SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahAllocationThreshold,  10);
> +    SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahImmediateThreshold,   100);
>      SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahUncommitDelay,        5000);
>      SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahGuaranteedGCInterval, 30000);
>      SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahGarbageThreshold,     20);
> 
> Testing: hotspot_gc_shenandoah
> 
> Thanks,
> -Aleksey
> 

Yup