Excessive GC on whole heap only #7508
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@dmitripivkine please, review |
dmitripivkine
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@babsingh Would you please help to merge? |
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When excessive GC criteria is evaluated, beside GC throughput overhead, reclaimed memory is considered too, which is meaningful on Global GCs only. However, there are collectors (like Balanced PGC in OpenJ9) that are global in a sense that may collect ANY part/subset of the heap, but not necessarily the whole heap. This may lead to premature excessive GC where such GCs are frequent, and their reclaim memory is very low hence meeting the criteria, although effectively irrelevant. This change strengthens the global GC criteria by also considering the GC cycle type (beside just the type of subclass of MM_Collector), so that only STW Whole Heap GCs are considered for memory reclamation criteria. Signed-off-by: Aleksandar Micic <Aleksandar_Micic@ca.ibm.com>
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jenkins build all |
babsingh
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I think we can get fine tuning in the future, this one allows us to avoid false Excessive GC triggering for now.
babsingh
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When excessive GC criteria is evaluated, beside GC throughput overhead,
reclaimed memory is considered too, which is meaningful on Global GCs
only.
However, there are collectors (like Balanced PGC in OpenJ9) that are
global in a sense that may collect ANY part/subset of the heap, but not
necessarily the whole heap. This may lead to premature excessive GC
where such GCs are frequent, and their reclaim memory is very low hence
meeting the criteria, although effectively irrelevant.
This change strengthens the global GC criteria by also considering the
GC cycle type (beside just the type of subclass of MM_Collector), so
that only STW Whole Heap GCs are considered for memory reclamation
criteria.
Signed-off-by: Aleksandar Micic Aleksandar_Micic@ca.ibm.com