Question regarding JEP 8204089 Timely Reducing Unused Committed Memory

[Sunny Chan, CLSA]

(resending for hotspot-gc-dev)

Hello,

I have a number of question about the proposed changes for the JEP and I would like to make the following suggestions and comments


1)      Are we planning to make this change the default behavior for G1? Or this is an optional switch for people who runs in a container environment?

2)      In a trading systems, sometimes there are period of quiescence and then suddenly a burst of activity towards market close or market event. The loadavg you suggest to "monitor" the activity in the system only reports up to 14mins and it might not necessary a good measure for this type of applications, especially you would trigger a Full GC

3)      You haven't fill in the details for "The GCFrequency value is ignored and therefore, i.e., no full collection is triggered, if:"

4)      If we are trigging full GC with this we should make sure the GC reason is populated and log properly in the GC log so we can track it down.

5)      I have not heard of J9 Gencon/Shenandoah providing similar functionality. Can you point me to further documentation on which feature you model upon?

Thanks.

Sunny Chan
Senior Lead Engineer, Executive Services
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