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6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads

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Select number of GC threads dynamically based on heap usage and number of Java threads

Reviewed-by: johnc, ysr, jcoomes
This commit is contained in:
Jon Masamitsu 2011-08-09 10:16:01 -07:00
parent 098ed89645
commit 15070123fa
39 changed files with 1523 additions and 231 deletions
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9
hotspot/src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.cpp
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@ -223,7 +223,8 @@ void CardTableExtension::scavenge_contents_parallel(ObjectStartArray* start_arra
MutableSpace* sp,
HeapWord* space_top,
PSPromotionManager* pm,
uint stripe_number) {
uint stripe_number,
uint stripe_total) {
int ssize = 128; // Naked constant! Work unit = 64k.
int dirty_card_count = 0;
@ -231,7 +232,11 @@ void CardTableExtension::scavenge_contents_parallel(ObjectStartArray* start_arra
jbyte* start_card = byte_for(sp->bottom());
jbyte* end_card = byte_for(sp_top - 1) + 1;
oop* last_scanned = NULL; // Prevent scanning objects more than once
for (jbyte* slice = start_card; slice < end_card; slice += ssize*ParallelGCThreads) {
// The width of the stripe ssize*stripe_total must be
// consistent with the number of stripes so that the complete slice
// is covered.
size_t slice_width = ssize * stripe_total;
for (jbyte* slice = start_card; slice < end_card; slice += slice_width) {
jbyte* worker_start_card = slice + stripe_number * ssize;
if (worker_start_card >= end_card)
return; // We're done.