RFR: Pauses that do not affect heap occupancy should not report heap

[Christine Flood]

I think it's confusing that phases that don't do any reclamation report
heap sizes increasing.
Maybe we should only report the heap changes that go down at concurrent
cleanup?

[19.889s][info][gc] GC(5) Concurrent partial GC 21740M->21828M(102400M) 10.035ms


To someone used to reading hotspot logs, that looks like an unsuccessful gc.


Christine




On Wed, Oct 11, 2017 at 11:14 AM, Zhengyu Gu <zgu at redhat.com> wrote:

> Good to me too.
>
> -Zhengyu
>
>
> On 10/11/2017 08:11 AM, Roman Kennke wrote:
>
>> Am 11.10.2017 um 13:38 schrieb Aleksey Shipilev:
>>
>>> http://cr.openjdk.java.net/~shade/shenandoah/stats-no-pause-
>>> heap/webrev.02/
>>>
>>> We have done this before for Init Mark. After async region recycling,
>>> Final Mark and Final Update
>>> Refs are not freeing up the heap themselves. Ditto for Init and Final
>>> Partial GC.
>>>
>>> Sample cycles:
>>>
>>> [19.879s][info][gc] GC(5) Pause Init Partial 2.188ms
>>> [19.889s][info][gc] GC(5) Concurrent partial GC 21740M->21828M(102400M)
>>> 10.035ms
>>> [19.890s][info][gc] GC(5) Pause Final Partial 1.028ms
>>> [19.894s][info][gc] GC(5) Concurrent cleanup 21828M->1312M(102400M)
>>> 4.296ms
>>>
>>> ...and:
>>>
>>> [121.084s][info][gc] GC(9) Pause Init Mark 0.776ms
>>> [121.317s][info][gc] GC(9) Concurrent marking 81944M->83220M(102400M)
>>> 232.421ms
>>> [121.320s][info][gc] GC(9) Concurrent precleaning
>>> 83220M->83236M(102400M) 3.476ms
>>> [121.356s][info][gc] GC(9) Pause Final Mark 35.520ms
>>> [121.356s][info][gc] GC(9) Concurrent cleanup 83264M->21162M(102400M)
>>> 0.305ms
>>> [121.441s][info][gc] GC(9) Concurrent evacuation
>>> 21162M->22165M(102400M) 84.215ms
>>> [121.441s][info][gc] GC(9) Pause Init Update Refs 0.050ms
>>> [121.698s][info][gc] GC(9) Concurrent update references
>>> 22169M->23389M(102400M) 256.810ms
>>> [121.699s][info][gc] GC(9) Pause Final Update Refs 0.522ms
>>> [121.700s][info][gc] GC(9) Concurrent cleanup 23389M->4630M(102400M)
>>> 0.859ms
>>>
>>> Testing: hotspot_gc_shenandoah
>>>
>>> Thanks,
>>> -Aleksey
>>>
>>> Ok looks good
>>
>>