26 #include "gc/shenandoah/shenandoahMetrics.hpp"
27 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
28 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
29 #include "gc/shenandoah/shenandoahFreeSet.hpp"
30
31 ShenandoahMetricsSnapshot::ShenandoahMetricsSnapshot() {
32 _heap = ShenandoahHeap::heap();
33 }
34
35 void ShenandoahMetricsSnapshot::snap_before() {
36 _used_before = _heap->used();
37 _if_before = _heap->free_set()->internal_fragmentation();
38 _ef_before = _heap->free_set()->external_fragmentation();
39 }
40 void ShenandoahMetricsSnapshot::snap_after() {
41 _used_after = _heap->used();
42 _if_after = _heap->free_set()->internal_fragmentation();
43 _ef_after = _heap->free_set()->external_fragmentation();
44 }
45
46 bool ShenandoahMetricsSnapshot::is_good_progress() {
47 // Under the critical threshold?
48 size_t free_actual = _heap->free_set()->available();
49 size_t free_expected = _heap->max_capacity() / 100 * ShenandoahCriticalFreeThreshold;
50 bool prog_free = free_actual >= free_expected;
51 log_info(gc, ergo)("%s progress for free space: " SIZE_FORMAT "%s, need " SIZE_FORMAT "%s",
52 prog_free ? "Good" : "Bad",
53 byte_size_in_proper_unit(free_actual), proper_unit_for_byte_size(free_actual),
54 byte_size_in_proper_unit(free_expected), proper_unit_for_byte_size(free_expected));
55 if (!prog_free) {
56 return false;
57 }
58
59 // Freed up enough?
60 size_t progress_actual = (_used_before > _used_after) ? _used_before - _used_after : 0;
61 size_t progress_expected = ShenandoahHeapRegion::region_size_bytes();
62 bool prog_used = progress_actual >= progress_expected;
63 log_info(gc, ergo)("%s progress for used space: " SIZE_FORMAT "%s, need " SIZE_FORMAT "%s",
64 prog_used ? "Good" : "Bad",
65 byte_size_in_proper_unit(progress_actual), proper_unit_for_byte_size(progress_actual),
66 byte_size_in_proper_unit(progress_expected), proper_unit_for_byte_size(progress_expected));
67 if (prog_used) {
68 return true;
69 }
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26 #include "gc/shenandoah/shenandoahMetrics.hpp"
27 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
28 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
29 #include "gc/shenandoah/shenandoahFreeSet.hpp"
30
31 ShenandoahMetricsSnapshot::ShenandoahMetricsSnapshot() {
32 _heap = ShenandoahHeap::heap();
33 }
34
35 void ShenandoahMetricsSnapshot::snap_before() {
36 _used_before = _heap->used();
37 _if_before = _heap->free_set()->internal_fragmentation();
38 _ef_before = _heap->free_set()->external_fragmentation();
39 }
40 void ShenandoahMetricsSnapshot::snap_after() {
41 _used_after = _heap->used();
42 _if_after = _heap->free_set()->internal_fragmentation();
43 _ef_after = _heap->free_set()->external_fragmentation();
44 }
45
46 // For degenerated GC, generation is Young in generational mode, Global in non-generational mode.
47 // For full GC, generation is always Global.
48 //
49 // Note that the size of the chosen collection set is proportional to the relevant generation's collection set.
50 // Note also that the generation size may change following selection of the collection set, as a side effect
51 // of evacuation. Evacuation may promote objects, causing old to grow and young to shrink. Or this may be a
52 // mixed evacuation. When old regions are evacuated, this typically allows young to expand. In all of these
53 // various scenarios, the purpose of asking is_good_progress() is to determine if there is enough memory available
54 // within young generation to justify making an attempt to perform a concurrent collection. For this reason, we'll
55 // use the current size of the generation (which may not be different than when the collection set was chosen) to
56 // assess how much free memory we require in order to consider the most recent GC to have had good progress.
57
58 bool ShenandoahMetricsSnapshot::is_good_progress(ShenandoahGeneration* generation) {
59 // Under the critical threshold?
60 ShenandoahFreeSet* free_set = _heap->free_set();
61 size_t free_actual = free_set->available();
62
63 // ShenandoahCriticalFreeThreshold is expressed as a percentage. We multiple this percentage by 1/100th
64 // of the generation capacity to determine whether the available memory within the generation exceeds the
65 // critical threshold.
66 size_t free_expected = (generation->max_capacity() / 100) * ShenandoahCriticalFreeThreshold;
67
68 bool prog_free = free_actual >= free_expected;
69 log_info(gc, ergo)("%s progress for free space: " SIZE_FORMAT "%s, need " SIZE_FORMAT "%s",
70 prog_free ? "Good" : "Bad",
71 byte_size_in_proper_unit(free_actual), proper_unit_for_byte_size(free_actual),
72 byte_size_in_proper_unit(free_expected), proper_unit_for_byte_size(free_expected));
73 if (!prog_free) {
74 return false;
75 }
76
77 // Freed up enough?
78 size_t progress_actual = (_used_before > _used_after) ? _used_before - _used_after : 0;
79 size_t progress_expected = ShenandoahHeapRegion::region_size_bytes();
80 bool prog_used = progress_actual >= progress_expected;
81 log_info(gc, ergo)("%s progress for used space: " SIZE_FORMAT "%s, need " SIZE_FORMAT "%s",
82 prog_used ? "Good" : "Bad",
83 byte_size_in_proper_unit(progress_actual), proper_unit_for_byte_size(progress_actual),
84 byte_size_in_proper_unit(progress_expected), proper_unit_for_byte_size(progress_expected));
85 if (prog_used) {
86 return true;
87 }
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