37
38 // static member initialization
39 size_t ThreadLocalAllocBuffer::_max_size = 0;
40 int ThreadLocalAllocBuffer::_reserve_for_allocation_prefetch = 0;
41 unsigned ThreadLocalAllocBuffer::_target_refills = 0;
42 GlobalTLABStats* ThreadLocalAllocBuffer::_global_stats = NULL;
43
44 void ThreadLocalAllocBuffer::clear_before_allocation() {
45 _slow_refill_waste += (unsigned)remaining();
46 make_parsable(true); // also retire the TLAB
47 }
48
49 void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() {
50 global_stats()->initialize();
51
52 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
53 thread->tlab().accumulate_statistics();
54 thread->tlab().initialize_statistics();
55 }
56
57 Universe::heap()->accumulate_statistics_all_gclabs();
58
59 // Publish new stats if some allocation occurred.
60 if (global_stats()->allocation() != 0) {
61 global_stats()->publish();
62 global_stats()->print();
63 }
64 }
65
66 void ThreadLocalAllocBuffer::accumulate_statistics() {
67 Thread* thread = myThread();
68 size_t capacity = Universe::heap()->tlab_capacity(thread);
69 size_t used = Universe::heap()->tlab_used(thread);
70
71 _gc_waste += (unsigned)remaining();
72 size_t total_allocated = _gclab ? thread->allocated_bytes_gclab() : thread->allocated_bytes();
73 size_t allocated_since_last_gc = total_allocated - _allocated_before_last_gc;
74 _allocated_before_last_gc = total_allocated;
75
76 print_stats("gc");
77
78 if (_number_of_refills > 0) {
79 // Update allocation history if a reasonable amount of eden was allocated.
80 bool update_allocation_history = used > 0.5 * capacity;
81
82 if (update_allocation_history) {
83 // Average the fraction of eden allocated in a tlab by this
84 // thread for use in the next resize operation.
85 // _gc_waste is not subtracted because it's included in
86 // "used".
87 // The result can be larger than 1.0 due to direct to old allocations.
88 // These allocations should ideally not be counted but since it is not possible
89 // to filter them out here we just cap the fraction to be at most 1.0.
90 double alloc_frac = MIN2(1.0, (double) allocated_since_last_gc / used);
91 _allocation_fraction.sample(alloc_frac);
92 }
97 global_stats()->update_slow_refill_waste(_slow_refill_waste);
98 global_stats()->update_fast_refill_waste(_fast_refill_waste);
99
100 } else {
101 assert(_number_of_refills == 0 && _fast_refill_waste == 0 &&
102 _slow_refill_waste == 0 && _gc_waste == 0,
103 "tlab stats == 0");
104 }
105 global_stats()->update_slow_allocations(_slow_allocations);
106 }
107
108 // Fills the current tlab with a dummy filler array to create
109 // an illusion of a contiguous Eden and optionally retires the tlab.
110 // Waste accounting should be done in caller as appropriate; see,
111 // for example, clear_before_allocation().
112 void ThreadLocalAllocBuffer::make_parsable(bool retire, bool zap) {
113 if (end() != NULL) {
114 invariants();
115
116 if (retire) {
117 if (_gclab) {
118 myThread()->incr_allocated_bytes_gclab(used_bytes());
119 } else {
120 myThread()->incr_allocated_bytes(used_bytes());
121 }
122 }
123
124 HeapWord* obj = Universe::heap()->tlab_post_allocation_setup(top());
125 CollectedHeap::fill_with_object(obj, hard_end(), retire && zap);
126
127 if (retire || ZeroTLAB) { // "Reset" the TLAB
128 set_start(NULL);
129 set_top(NULL);
130 set_pf_top(NULL);
131 set_end(NULL);
132 }
133 }
134 assert(!(retire || ZeroTLAB) ||
135 (start() == NULL && end() == NULL && top() == NULL),
136 "TLAB must be reset");
137 }
138
139 void ThreadLocalAllocBuffer::resize_all_tlabs() {
140 if (ResizeTLAB) {
141 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
142 thread->tlab().resize();
177 size_t new_size) {
178 _number_of_refills++;
179 print_stats("fill");
180 assert(top <= start + new_size - alignment_reserve(), "size too small");
181 initialize(start, top, start + new_size - alignment_reserve());
182
183 // Reset amount of internal fragmentation
184 set_refill_waste_limit(initial_refill_waste_limit());
185 }
186
187 void ThreadLocalAllocBuffer::initialize(HeapWord* start,
188 HeapWord* top,
189 HeapWord* end) {
190 set_start(start);
191 set_top(top);
192 set_pf_top(top);
193 set_end(end);
194 invariants();
195 }
196
197 void ThreadLocalAllocBuffer::initialize(bool gclab) {
198 _initialized = true;
199 _gclab = gclab;
200 initialize(NULL, // start
201 NULL, // top
202 NULL); // end
203
204 set_desired_size(initial_desired_size());
205
206 // Following check is needed because at startup the main
207 // thread is initialized before the heap is. The initialization for
208 // this thread is redone in startup_initialization below.
209 if (Universe::heap() != NULL) {
210 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize;
211 double alloc_frac = desired_size() * target_refills() / (double) capacity;
212 _allocation_fraction.sample(alloc_frac);
213 }
214
215 set_refill_waste_limit(initial_refill_waste_limit());
216
217 initialize_statistics();
218 }
219
236 //
237 // Only SPARC-specific BIS instructions are known to fault. (Those
238 // instructions are generated if AllocatePrefetchStyle==3 and
239 // AllocatePrefetchInstr==1). To be on the safe side, however,
240 // extra space is reserved for all combinations of
241 // AllocatePrefetchStyle and AllocatePrefetchInstr.
242 //
243 // If the C2 compiler is not present, no space is reserved.
244
245 // +1 for rounding up to next cache line, +1 to be safe
246 if (is_server_compilation_mode_vm()) {
247 int lines = MAX2(AllocatePrefetchLines, AllocateInstancePrefetchLines) + 2;
248 _reserve_for_allocation_prefetch = (AllocatePrefetchDistance + AllocatePrefetchStepSize * lines) /
249 (int)HeapWordSize;
250 }
251 #endif
252
253 // During jvm startup, the main thread is initialized
254 // before the heap is initialized. So reinitialize it now.
255 guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread");
256 Thread::current()->tlab().initialize(false);
257 Thread::current()->gclab().initialize(true);
258
259 log_develop_trace(gc, tlab)("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT,
260 min_size(), Thread::current()->tlab().initial_desired_size(), max_size());
261 }
262
263 size_t ThreadLocalAllocBuffer::initial_desired_size() {
264 size_t init_sz = 0;
265
266 if (TLABSize > 0) {
267 init_sz = TLABSize / HeapWordSize;
268 } else if (global_stats() != NULL) {
269 // Initial size is a function of the average number of allocating threads.
270 unsigned nof_threads = global_stats()->allocating_threads_avg();
271
272 init_sz = (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize) /
273 (nof_threads * target_refills());
274 init_sz = align_object_size(init_sz);
275 }
276 init_sz = MIN2(MAX2(init_sz, min_size()), max_size());
277 return init_sz;
300 _allocation_fraction.average() * tlab_used / K,
301 _number_of_refills, waste_percent,
302 _gc_waste * HeapWordSize,
303 _slow_refill_waste * HeapWordSize,
304 _fast_refill_waste * HeapWordSize);
305 }
306
307 void ThreadLocalAllocBuffer::verify() {
308 HeapWord* p = start();
309 HeapWord* t = top();
310 HeapWord* prev_p = NULL;
311 while (p < t) {
312 oop(p)->verify();
313 prev_p = p;
314 p += oop(p)->size();
315 }
316 guarantee(p == top(), "end of last object must match end of space");
317 }
318
319 Thread* ThreadLocalAllocBuffer::myThread() {
320 ByteSize gclab_offset = Thread::gclab_start_offset();
321 ByteSize tlab_offset = Thread::tlab_start_offset();
322 ByteSize offs = _gclab ? gclab_offset : tlab_offset;
323 Thread* thread = (Thread*)(((char *)this) +
324 in_bytes(start_offset()) - in_bytes(offs));
325 #ifdef ASSERT
326 assert(this == (_gclab ? &thread->gclab() : &thread->tlab()), "must be");
327 #endif
328 return thread;
329 }
330
331 size_t ThreadLocalAllocBuffer::end_reserve() {
332 int reserve_size = typeArrayOopDesc::header_size(T_INT);
333 return MAX2(reserve_size, _reserve_for_allocation_prefetch);
334 }
335
336 void ThreadLocalAllocBuffer::rollback(size_t size) {
337 HeapWord* old_top = top();
338 if (old_top != NULL) { // Pathological case: we accept that we can't rollback.
339 set_top(old_top - size);
340 }
341 }
342
343
344 GlobalTLABStats::GlobalTLABStats() :
345 _allocating_threads_avg(TLABAllocationWeight) {
346
347 initialize();
348
349 _allocating_threads_avg.sample(1); // One allocating thread at startup
350
351 if (UsePerfData) {
352
353 EXCEPTION_MARK;
354 ResourceMark rm;
355
356 char* cname = PerfDataManager::counter_name("tlab", "allocThreads");
357 _perf_allocating_threads =
358 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
359
360 cname = PerfDataManager::counter_name("tlab", "fills");
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37
38 // static member initialization
39 size_t ThreadLocalAllocBuffer::_max_size = 0;
40 int ThreadLocalAllocBuffer::_reserve_for_allocation_prefetch = 0;
41 unsigned ThreadLocalAllocBuffer::_target_refills = 0;
42 GlobalTLABStats* ThreadLocalAllocBuffer::_global_stats = NULL;
43
44 void ThreadLocalAllocBuffer::clear_before_allocation() {
45 _slow_refill_waste += (unsigned)remaining();
46 make_parsable(true); // also retire the TLAB
47 }
48
49 void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() {
50 global_stats()->initialize();
51
52 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
53 thread->tlab().accumulate_statistics();
54 thread->tlab().initialize_statistics();
55 }
56
57 // Publish new stats if some allocation occurred.
58 if (global_stats()->allocation() != 0) {
59 global_stats()->publish();
60 global_stats()->print();
61 }
62 }
63
64 void ThreadLocalAllocBuffer::accumulate_statistics() {
65 Thread* thread = myThread();
66 size_t capacity = Universe::heap()->tlab_capacity(thread);
67 size_t used = Universe::heap()->tlab_used(thread);
68
69 _gc_waste += (unsigned)remaining();
70 size_t total_allocated = thread->allocated_bytes();
71 size_t allocated_since_last_gc = total_allocated - _allocated_before_last_gc;
72 _allocated_before_last_gc = total_allocated;
73
74 print_stats("gc");
75
76 if (_number_of_refills > 0) {
77 // Update allocation history if a reasonable amount of eden was allocated.
78 bool update_allocation_history = used > 0.5 * capacity;
79
80 if (update_allocation_history) {
81 // Average the fraction of eden allocated in a tlab by this
82 // thread for use in the next resize operation.
83 // _gc_waste is not subtracted because it's included in
84 // "used".
85 // The result can be larger than 1.0 due to direct to old allocations.
86 // These allocations should ideally not be counted but since it is not possible
87 // to filter them out here we just cap the fraction to be at most 1.0.
88 double alloc_frac = MIN2(1.0, (double) allocated_since_last_gc / used);
89 _allocation_fraction.sample(alloc_frac);
90 }
95 global_stats()->update_slow_refill_waste(_slow_refill_waste);
96 global_stats()->update_fast_refill_waste(_fast_refill_waste);
97
98 } else {
99 assert(_number_of_refills == 0 && _fast_refill_waste == 0 &&
100 _slow_refill_waste == 0 && _gc_waste == 0,
101 "tlab stats == 0");
102 }
103 global_stats()->update_slow_allocations(_slow_allocations);
104 }
105
106 // Fills the current tlab with a dummy filler array to create
107 // an illusion of a contiguous Eden and optionally retires the tlab.
108 // Waste accounting should be done in caller as appropriate; see,
109 // for example, clear_before_allocation().
110 void ThreadLocalAllocBuffer::make_parsable(bool retire, bool zap) {
111 if (end() != NULL) {
112 invariants();
113
114 if (retire) {
115 myThread()->incr_allocated_bytes(used_bytes());
116 }
117
118 HeapWord* obj = Universe::heap()->tlab_post_allocation_setup(top());
119 CollectedHeap::fill_with_object(obj, hard_end(), retire && zap);
120
121 if (retire || ZeroTLAB) { // "Reset" the TLAB
122 set_start(NULL);
123 set_top(NULL);
124 set_pf_top(NULL);
125 set_end(NULL);
126 }
127 }
128 assert(!(retire || ZeroTLAB) ||
129 (start() == NULL && end() == NULL && top() == NULL),
130 "TLAB must be reset");
131 }
132
133 void ThreadLocalAllocBuffer::resize_all_tlabs() {
134 if (ResizeTLAB) {
135 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
136 thread->tlab().resize();
171 size_t new_size) {
172 _number_of_refills++;
173 print_stats("fill");
174 assert(top <= start + new_size - alignment_reserve(), "size too small");
175 initialize(start, top, start + new_size - alignment_reserve());
176
177 // Reset amount of internal fragmentation
178 set_refill_waste_limit(initial_refill_waste_limit());
179 }
180
181 void ThreadLocalAllocBuffer::initialize(HeapWord* start,
182 HeapWord* top,
183 HeapWord* end) {
184 set_start(start);
185 set_top(top);
186 set_pf_top(top);
187 set_end(end);
188 invariants();
189 }
190
191 void ThreadLocalAllocBuffer::initialize() {
192 initialize(NULL, // start
193 NULL, // top
194 NULL); // end
195
196 set_desired_size(initial_desired_size());
197
198 // Following check is needed because at startup the main
199 // thread is initialized before the heap is. The initialization for
200 // this thread is redone in startup_initialization below.
201 if (Universe::heap() != NULL) {
202 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize;
203 double alloc_frac = desired_size() * target_refills() / (double) capacity;
204 _allocation_fraction.sample(alloc_frac);
205 }
206
207 set_refill_waste_limit(initial_refill_waste_limit());
208
209 initialize_statistics();
210 }
211
228 //
229 // Only SPARC-specific BIS instructions are known to fault. (Those
230 // instructions are generated if AllocatePrefetchStyle==3 and
231 // AllocatePrefetchInstr==1). To be on the safe side, however,
232 // extra space is reserved for all combinations of
233 // AllocatePrefetchStyle and AllocatePrefetchInstr.
234 //
235 // If the C2 compiler is not present, no space is reserved.
236
237 // +1 for rounding up to next cache line, +1 to be safe
238 if (is_server_compilation_mode_vm()) {
239 int lines = MAX2(AllocatePrefetchLines, AllocateInstancePrefetchLines) + 2;
240 _reserve_for_allocation_prefetch = (AllocatePrefetchDistance + AllocatePrefetchStepSize * lines) /
241 (int)HeapWordSize;
242 }
243 #endif
244
245 // During jvm startup, the main thread is initialized
246 // before the heap is initialized. So reinitialize it now.
247 guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread");
248 Thread::current()->tlab().initialize();
249
250 log_develop_trace(gc, tlab)("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT,
251 min_size(), Thread::current()->tlab().initial_desired_size(), max_size());
252 }
253
254 size_t ThreadLocalAllocBuffer::initial_desired_size() {
255 size_t init_sz = 0;
256
257 if (TLABSize > 0) {
258 init_sz = TLABSize / HeapWordSize;
259 } else if (global_stats() != NULL) {
260 // Initial size is a function of the average number of allocating threads.
261 unsigned nof_threads = global_stats()->allocating_threads_avg();
262
263 init_sz = (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize) /
264 (nof_threads * target_refills());
265 init_sz = align_object_size(init_sz);
266 }
267 init_sz = MIN2(MAX2(init_sz, min_size()), max_size());
268 return init_sz;
291 _allocation_fraction.average() * tlab_used / K,
292 _number_of_refills, waste_percent,
293 _gc_waste * HeapWordSize,
294 _slow_refill_waste * HeapWordSize,
295 _fast_refill_waste * HeapWordSize);
296 }
297
298 void ThreadLocalAllocBuffer::verify() {
299 HeapWord* p = start();
300 HeapWord* t = top();
301 HeapWord* prev_p = NULL;
302 while (p < t) {
303 oop(p)->verify();
304 prev_p = p;
305 p += oop(p)->size();
306 }
307 guarantee(p == top(), "end of last object must match end of space");
308 }
309
310 Thread* ThreadLocalAllocBuffer::myThread() {
311 return (Thread*)(((char *)this) +
312 in_bytes(start_offset()) -
313 in_bytes(Thread::tlab_start_offset()));
314 }
315
316
317 GlobalTLABStats::GlobalTLABStats() :
318 _allocating_threads_avg(TLABAllocationWeight) {
319
320 initialize();
321
322 _allocating_threads_avg.sample(1); // One allocating thread at startup
323
324 if (UsePerfData) {
325
326 EXCEPTION_MARK;
327 ResourceMark rm;
328
329 char* cname = PerfDataManager::counter_name("tlab", "allocThreads");
330 _perf_allocating_threads =
331 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
332
333 cname = PerfDataManager::counter_name("tlab", "fills");
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