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src/share/vm/gc/g1/g1IHOPControl.hpp
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rev 9402 : dihop-changes
rev 9403 : imported patch sihop-thomas-review
rev 9404 : [mq]: erik-jmasa-review
@@ -24,55 +24,69 @@
#ifndef SHARE_VM_GC_G1_G1IHOPCONTROL_HPP
#define SHARE_VM_GC_G1_G1IHOPCONTROL_HPP
#include "memory/allocation.hpp"
-#include "utilities/numberSeq.hpp"
-class G1Predictions;
-
-// Manages the decision about the threshold when concurrent marking should start.
+// Base class for algorithms that calculate the heap occupancy at which
+// concurrent marking should start. This heap usage threshold should be relative
+// to old gen size.
class G1IHOPControl : public CHeapObj<mtGC> {
protected:
- double _ihop_percent;
+ // The initial IHOP value relative to the target occupancy.
+ double _initial_ihop_percent;
+ // The target maximum occupancy of the heap.
size_t _target_occupancy;
// Initialize an instance with the initial IHOP value in percent and the target
// occupancy. The target occupancy is the number of bytes when marking should
// be finished and reclaim started.
G1IHOPControl(double initial_ihop_percent, size_t target_occupancy);
public:
virtual ~G1IHOPControl() { }
- // Get the current marking threshold in bytes.
+ // Get the current non-young occupancy at which concurrent marking should start.
virtual size_t get_conc_mark_start_threshold() = 0;
- // Update information about recent time during which allocations happened,
- // how many allocations happened and an additional safety buffer.
+ // Update information about time during which allocations in the Java heap occurred,
+ // how large these allocations were in bytes, and an additional buffer.
+ // The allocations should contain any amount of space made unusable for further
+ // allocation, e.g. any waste caused by TLAB allocation, space at the end of
+ // humongous objects that can not be used for allocation, etc.
+ // Together with the target occupancy, this additional buffer should contain the
+ // difference between old gen size and total heap size at the start of reclamation,
+ // and space required for that reclamation.
virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) = 0;
- // Update the time from the end of initial mark to the first mixed gc.
- virtual void update_time_to_mixed(double marking_length_s) = 0;
+ // Update the time spent in the mutator beginning from the end of initial mark to
+ // the first mixed gc.
+ virtual void update_marking_length(double marking_length_s) = 0;
virtual void print() = 0;
};
+// The returned concurrent mark starting occupancy threshold is a fixed value
+// relative to the maximum heap size.
class G1StaticIHOPControl : public G1IHOPControl {
+ // Most recent complete mutator allocation period in seconds.
double _last_allocation_time_s;
+ // Amount of bytes allocated during _last_allocation_time_s.
size_t _last_allocated_bytes;
+ // Most recent mutator time between the end of initial mark to the start of the
+ // first mixed gc.
double _last_marking_length_s;
public:
G1StaticIHOPControl(double ihop_percent, size_t target_occupancy);
- size_t get_conc_mark_start_threshold() { return (size_t) (_ihop_percent * _target_occupancy / 100.0); }
+ size_t get_conc_mark_start_threshold() { return (size_t) (_initial_ihop_percent * _target_occupancy / 100.0); }
virtual void update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) {
assert(allocation_time_s >= 0.0, "Allocation time must be positive but is %.3f", allocation_time_s);
_last_allocation_time_s = allocation_time_s;
_last_allocated_bytes = allocated_bytes;
}
- virtual void update_time_to_mixed(double marking_length_s) {
+ virtual void update_marking_length(double marking_length_s) {
assert(marking_length_s > 0.0, "Marking length must be larger than zero but is %.3f", marking_length_s);
_last_marking_length_s = marking_length_s;
}
virtual void print();
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