8223162: Improve ergonomics for Sparse PRT entry sizing
Summary: Scale Sparse PRT table sizes exponentially according to region size.
Reviewed-by: kbarrett, sangheki
--- a/src/hotspot/share/gc/g1/heapRegionRemSet.cpp Sun Jun 02 17:13:31 2019 -0400
+++ b/src/hotspot/share/gc/g1/heapRegionRemSet.cpp Mon Jun 03 10:50:14 2019 +0200
@@ -614,12 +614,12 @@
}
void HeapRegionRemSet::setup_remset_size() {
- // Setup sparse and fine-grain tables sizes.
- // table_size = base * (log(region_size / 1M) + 1)
const int LOG_M = 20;
- int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0);
+ guarantee(HeapRegion::LogOfHRGrainBytes >= LOG_M, "Code assumes the region size >= 1M, but is " SIZE_FORMAT "B", HeapRegion::GrainBytes);
+
+ int region_size_log_mb = HeapRegion::LogOfHRGrainBytes - LOG_M;
if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) {
- G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1);
+ G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * ((size_t)1 << (region_size_log_mb + 1));
}
if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) {
G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1);
--- a/src/hotspot/share/gc/g1/heapRegionRemSet.hpp Sun Jun 02 17:13:31 2019 -0400
+++ b/src/hotspot/share/gc/g1/heapRegionRemSet.hpp Mon Jun 03 10:50:14 2019 +0200
@@ -179,6 +179,7 @@
public:
HeapRegionRemSet(G1BlockOffsetTable* bot, HeapRegion* hr);
+ // Setup sparse and fine-grain tables sizes.
static void setup_remset_size();
bool cardset_is_empty() const {
--- a/src/hotspot/share/gc/g1/sparsePRT.hpp Sun Jun 02 17:13:31 2019 -0400
+++ b/src/hotspot/share/gc/g1/sparsePRT.hpp Mon Jun 03 10:50:14 2019 +0200
@@ -218,9 +218,7 @@
RSHashTable* _table;
- enum SomeAdditionalPrivateConstants {
- InitialCapacity = 16
- };
+ static const size_t InitialCapacity = 8;
void expand();