Runtime.getRuntime().freeMemory() with ZGC
per.liden at oracle.com
Tue Jun 8 07:07:28 UTC 2021
On 6/4/21 5:25 PM, Mike Rettig wrote:
> On Thu, Jun 3, 2021 at 11:25 AM Per Liden <per.liden at oracle.com
> <mailto:per.liden at oracle.com>> wrote:
> If "Proactive" GCs kick more frequently than the ZCollectionInterval
> want to use, then disabling it (-XX:-ZProactive) is a good idea.
> As you said before, ZProactive collections run when impact should be
> minimal. Is there any other criteria for it to run? I disabled it
It only runs if it thinks it will have minimal impact.
> because it was too aggressive. It was running frequently even if the
> heap usage was really low. Is there a heap usage (current heap not -Xmx)
> threshold? I think that could be even better than a max pause
> threshold. If I could configure proactive collections to run only if
> the current heap usage > 75% then GC performance would be ideal. ZGC
> would be able to grow/shrink the heap as needed while also minimizing
> the impact on the app.
Check. Yes, proactive GCs can currently only be turned on or off, i.e.
there is currently no other configuration option to influence it.
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