Thu, 12 Jan 2012 00:06:47 -0800
6484965: G1: piggy-back liveness accounting phase on marking
Summary: Remove the separate counting phase of concurrent marking by tracking the amount of marked bytes and the cards spanned by marked objects in marking task/worker thread local data structures, which are updated as individual objects are marked.
Reviewed-by: brutisso, tonyp
1 /*
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25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1MonitoringSupport.hpp"
27 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
28 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
30 G1GenerationCounters::G1GenerationCounters(G1MonitoringSupport* g1mm,
31 const char* name,
32 int ordinal, int spaces,
33 size_t min_capacity,
34 size_t max_capacity,
35 size_t curr_capacity)
36 : GenerationCounters(name, ordinal, spaces, min_capacity,
37 max_capacity, curr_capacity), _g1mm(g1mm) { }
39 // We pad the capacity three times given that the young generation
40 // contains three spaces (eden and two survivors).
41 G1YoungGenerationCounters::G1YoungGenerationCounters(G1MonitoringSupport* g1mm,
42 const char* name)
43 : G1GenerationCounters(g1mm, name, 0 /* ordinal */, 3 /* spaces */,
44 G1MonitoringSupport::pad_capacity(0, 3) /* min_capacity */,
45 G1MonitoringSupport::pad_capacity(g1mm->young_gen_max(), 3),
46 G1MonitoringSupport::pad_capacity(0, 3) /* curr_capacity */) {
47 update_all();
48 }
50 G1OldGenerationCounters::G1OldGenerationCounters(G1MonitoringSupport* g1mm,
51 const char* name)
52 : G1GenerationCounters(g1mm, name, 1 /* ordinal */, 1 /* spaces */,
53 G1MonitoringSupport::pad_capacity(0) /* min_capacity */,
54 G1MonitoringSupport::pad_capacity(g1mm->old_gen_max()),
55 G1MonitoringSupport::pad_capacity(0) /* curr_capacity */) {
56 update_all();
57 }
59 void G1YoungGenerationCounters::update_all() {
60 size_t committed =
61 G1MonitoringSupport::pad_capacity(_g1mm->young_gen_committed(), 3);
62 _current_size->set_value(committed);
63 }
65 void G1OldGenerationCounters::update_all() {
66 size_t committed =
67 G1MonitoringSupport::pad_capacity(_g1mm->old_gen_committed());
68 _current_size->set_value(committed);
69 }
71 G1MonitoringSupport::G1MonitoringSupport(G1CollectedHeap* g1h) :
72 _g1h(g1h),
73 _incremental_collection_counters(NULL),
74 _full_collection_counters(NULL),
75 _old_collection_counters(NULL),
76 _old_space_counters(NULL),
77 _young_collection_counters(NULL),
78 _eden_counters(NULL),
79 _from_counters(NULL),
80 _to_counters(NULL),
82 _overall_reserved(0),
83 _overall_committed(0), _overall_used(0),
84 _young_region_num(0),
85 _young_gen_committed(0),
86 _eden_committed(0), _eden_used(0),
87 _survivor_committed(0), _survivor_used(0),
88 _old_committed(0), _old_used(0) {
90 _overall_reserved = g1h->max_capacity();
91 recalculate_sizes();
93 // Counters for GC collections
94 //
95 // name "collector.0". In a generational collector this would be the
96 // young generation collection.
97 _incremental_collection_counters =
98 new CollectorCounters("G1 incremental collections", 0);
99 // name "collector.1". In a generational collector this would be the
100 // old generation collection.
101 _full_collection_counters =
102 new CollectorCounters("G1 stop-the-world full collections", 1);
104 // timer sampling for all counters supporting sampling only update the
105 // used value. See the take_sample() method. G1 requires both used and
106 // capacity updated so sampling is not currently used. It might
107 // be sufficient to update all counters in take_sample() even though
108 // take_sample() only returns "used". When sampling was used, there
109 // were some anomolous values emitted which may have been the consequence
110 // of not updating all values simultaneously (i.e., see the calculation done
111 // in eden_space_used(), is it possbile that the values used to
112 // calculate either eden_used or survivor_used are being updated by
113 // the collector when the sample is being done?).
114 const bool sampled = false;
116 // "Generation" and "Space" counters.
117 //
118 // name "generation.1" This is logically the old generation in
119 // generational GC terms. The "1, 1" parameters are for
120 // the n-th generation (=1) with 1 space.
121 // Counters are created from minCapacity, maxCapacity, and capacity
122 _old_collection_counters = new G1OldGenerationCounters(this, "old");
124 // name "generation.1.space.0"
125 // Counters are created from maxCapacity, capacity, initCapacity,
126 // and used.
127 _old_space_counters = new HSpaceCounters("space", 0 /* ordinal */,
128 pad_capacity(overall_reserved()) /* max_capacity */,
129 pad_capacity(old_space_committed()) /* init_capacity */,
130 _old_collection_counters);
132 // Young collection set
133 // name "generation.0". This is logically the young generation.
134 // The "0, 3" are paremeters for the n-th genertaion (=0) with 3 spaces.
135 // See _old_collection_counters for additional counters
136 _young_collection_counters = new G1YoungGenerationCounters(this, "young");
138 // name "generation.0.space.0"
139 // See _old_space_counters for additional counters
140 _eden_counters = new HSpaceCounters("eden", 0 /* ordinal */,
141 pad_capacity(overall_reserved()) /* max_capacity */,
142 pad_capacity(eden_space_committed()) /* init_capacity */,
143 _young_collection_counters);
145 // name "generation.0.space.1"
146 // See _old_space_counters for additional counters
147 // Set the arguments to indicate that this survivor space is not used.
148 _from_counters = new HSpaceCounters("s0", 1 /* ordinal */,
149 pad_capacity(0) /* max_capacity */,
150 pad_capacity(0) /* init_capacity */,
151 _young_collection_counters);
152 // Given that this survivor space is not used, we update it here
153 // once to reflect that its used space is 0 so that we don't have to
154 // worry about updating it again later.
155 _from_counters->update_used(0);
157 // name "generation.0.space.2"
158 // See _old_space_counters for additional counters
159 _to_counters = new HSpaceCounters("s1", 2 /* ordinal */,
160 pad_capacity(overall_reserved()) /* max_capacity */,
161 pad_capacity(survivor_space_committed()) /* init_capacity */,
162 _young_collection_counters);
163 }
165 void G1MonitoringSupport::recalculate_sizes() {
166 G1CollectedHeap* g1 = g1h();
168 // Recalculate all the sizes from scratch. We assume that this is
169 // called at a point where no concurrent updates to the various
170 // values we read here are possible (i.e., at a STW phase at the end
171 // of a GC).
173 size_t young_list_length = g1->young_list()->length();
174 size_t survivor_list_length = g1->g1_policy()->recorded_survivor_regions();
175 assert(young_list_length >= survivor_list_length, "invariant");
176 size_t eden_list_length = young_list_length - survivor_list_length;
177 // Max length includes any potential extensions to the young gen
178 // we'll do when the GC locker is active.
179 size_t young_list_max_length = g1->g1_policy()->young_list_max_length();
180 assert(young_list_max_length >= survivor_list_length, "invariant");
181 size_t eden_list_max_length = young_list_max_length - survivor_list_length;
183 _overall_used = g1->used_unlocked();
184 _eden_used = eden_list_length * HeapRegion::GrainBytes;
185 _survivor_used = survivor_list_length * HeapRegion::GrainBytes;
186 _young_region_num = young_list_length;
187 _old_used = subtract_up_to_zero(_overall_used, _eden_used + _survivor_used);
189 // First calculate the committed sizes that can be calculated independently.
190 _survivor_committed = _survivor_used;
191 _old_committed = HeapRegion::align_up_to_region_byte_size(_old_used);
193 // Next, start with the overall committed size.
194 _overall_committed = g1->capacity();
195 size_t committed = _overall_committed;
197 // Remove the committed size we have calculated so far (for the
198 // survivor and old space).
199 assert(committed >= (_survivor_committed + _old_committed), "sanity");
200 committed -= _survivor_committed + _old_committed;
202 // Next, calculate and remove the committed size for the eden.
203 _eden_committed = eden_list_max_length * HeapRegion::GrainBytes;
204 // Somewhat defensive: be robust in case there are inaccuracies in
205 // the calculations
206 _eden_committed = MIN2(_eden_committed, committed);
207 committed -= _eden_committed;
209 // Finally, give the rest to the old space...
210 _old_committed += committed;
211 // ..and calculate the young gen committed.
212 _young_gen_committed = _eden_committed + _survivor_committed;
214 assert(_overall_committed ==
215 (_eden_committed + _survivor_committed + _old_committed),
216 "the committed sizes should add up");
217 // Somewhat defensive: cap the eden used size to make sure it
218 // never exceeds the committed size.
219 _eden_used = MIN2(_eden_used, _eden_committed);
220 // _survivor_committed and _old_committed are calculated in terms of
221 // the corresponding _*_used value, so the next two conditions
222 // should hold.
223 assert(_survivor_used <= _survivor_committed, "post-condition");
224 assert(_old_used <= _old_committed, "post-condition");
225 }
227 void G1MonitoringSupport::recalculate_eden_size() {
228 G1CollectedHeap* g1 = g1h();
230 // When a new eden region is allocated, only the eden_used size is
231 // affected (since we have recalculated everything else at the last GC).
233 size_t young_region_num = g1h()->young_list()->length();
234 if (young_region_num > _young_region_num) {
235 size_t diff = young_region_num - _young_region_num;
236 _eden_used += diff * HeapRegion::GrainBytes;
237 // Somewhat defensive: cap the eden used size to make sure it
238 // never exceeds the committed size.
239 _eden_used = MIN2(_eden_used, _eden_committed);
240 _young_region_num = young_region_num;
241 }
242 }
244 void G1MonitoringSupport::update_sizes() {
245 recalculate_sizes();
246 if (UsePerfData) {
247 eden_counters()->update_capacity(pad_capacity(eden_space_committed()));
248 eden_counters()->update_used(eden_space_used());
249 // only the to survivor space (s1) is active, so we don't need to
250 // update the counteres for the from survivor space (s0)
251 to_counters()->update_capacity(pad_capacity(survivor_space_committed()));
252 to_counters()->update_used(survivor_space_used());
253 old_space_counters()->update_capacity(pad_capacity(old_space_committed()));
254 old_space_counters()->update_used(old_space_used());
255 old_collection_counters()->update_all();
256 young_collection_counters()->update_all();
257 }
258 }
260 void G1MonitoringSupport::update_eden_size() {
261 recalculate_eden_size();
262 if (UsePerfData) {
263 eden_counters()->update_used(eden_space_used());
264 }
265 }