8364532: G1: In liveness tracing, print more significant digits for the liveness value

Reviewed-by: ayang, iwalulya

Author: Thomas Schatzl

src/hotspot/share/gc/g1/g1CollectionSetCandidates.cpp

@@ -63,10 +63,9 @@ void G1CSetCandidateGroup::calculate_efficiency() {
   _gc_efficiency = _reclaimable_bytes / predict_group_total_time_ms();
 }
 
-size_t G1CSetCandidateGroup::liveness() const {
+double G1CSetCandidateGroup::liveness_percent() const {
   size_t capacity = length() * G1HeapRegion::GrainBytes;
-
-  return (size_t) ceil(((capacity - _reclaimable_bytes) * 100.0) / capacity);
+  return ((capacity - _reclaimable_bytes) * 100.0) / capacity;
 }
 
 void G1CSetCandidateGroup::clear(bool uninstall_group_cardset) {

src/hotspot/share/gc/g1/g1CollectionSetCandidates.hpp

@@ -102,7 +102,7 @@ class G1CSetCandidateGroup : public CHeapObj<mtGCCardSet>{
 
   void calculate_efficiency();
 
-  size_t liveness() const;
+  double liveness_percent() const;
   // Comparison function to order regions in decreasing GC efficiency order. This
   // will cause regions with a lot of live objects and large remembered sets to end
   // up at the end of the list.

src/hotspot/share/gc/g1/g1ConcurrentMark.cpp

@@ -2981,6 +2981,7 @@ G1CMTask::G1CMTask(uint worker_id,
 #define G1PPRL_LEN_FORMAT             "  " UINT32_FORMAT_W(14)
 #define G1PPRL_LEN_H_FORMAT           "  %14s"
 #define G1PPRL_GID_GCEFF_FORMAT       "  %14.1f"
+#define G1PPRL_GID_LIVENESS_FORMAT    "  %9.2f"
 
 // For summary info
 #define G1PPRL_SUM_ADDR_FORMAT(tag)    "  " tag ":" G1PPRL_ADDR_BASE_FORMAT
@@ -3114,13 +3115,13 @@ void G1PrintRegionLivenessInfoClosure::log_cset_candidate_group_add_total(G1CSet
                           G1PPRL_GID_FORMAT
                           G1PPRL_LEN_FORMAT
                           G1PPRL_GID_GCEFF_FORMAT
-                          G1PPRL_BYTE_FORMAT
+                          G1PPRL_GID_LIVENESS_FORMAT
                           G1PPRL_BYTE_FORMAT
                           G1PPRL_TYPE_H_FORMAT,
                           group->group_id(),
                           group->length(),
                           group->gc_efficiency(),
-                          group->liveness(),
+                          group->liveness_percent(),
                           group->card_set()->mem_size(),
                           type);
   _total_remset_bytes += group->card_set()->mem_size();