1 /*
2 * Copyright (c) 1999, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/genCollectedHeap.hpp"
27 #include "memory/resourceArea.hpp"
28 #include "memory/threadLocalAllocBuffer.inline.hpp"
29 #include "memory/universe.inline.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "runtime/thread.inline.hpp"
32 #include "utilities/copy.hpp"
33
34 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
35
36 // Thread-Local Edens support
37
38 // static member initialization
39 size_t ThreadLocalAllocBuffer::_max_size = 0;
40 unsigned ThreadLocalAllocBuffer::_target_refills = 0;
41 GlobalTLABStats* ThreadLocalAllocBuffer::_global_stats = NULL;
42
43 void ThreadLocalAllocBuffer::clear_before_allocation() {
44 _slow_refill_waste += (unsigned)remaining();
45 make_parsable(true); // also retire the TLAB
46 }
47
48 void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() {
49 global_stats()->initialize();
50
51 for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) {
52 thread->tlab().accumulate_statistics();
53 thread->tlab().initialize_statistics();
54 }
55
56 // Publish new stats if some allocation occurred.
57 if (global_stats()->allocation() != 0) {
58 global_stats()->publish();
59 if (PrintTLAB) {
60 global_stats()->print();
61 }
62 }
63 }
64
65 void ThreadLocalAllocBuffer::accumulate_statistics() {
66 Thread* thread = myThread();
67 size_t capacity = Universe::heap()->tlab_capacity(thread);
68 size_t used = Universe::heap()->tlab_used(thread);
69
70 _gc_waste += (unsigned)remaining();
71 size_t total_allocated = thread->allocated_bytes();
72 size_t allocated_since_last_gc = total_allocated - _allocated_before_last_gc;
73 _allocated_before_last_gc = total_allocated;
74
75 if (PrintTLAB && (_number_of_refills > 0 || Verbose)) {
76 print_stats("gc");
77 }
78
79 if (_number_of_refills > 0) {
80 // Update allocation history if a reasonable amount of eden was allocated.
81 bool update_allocation_history = used > 0.5 * capacity;
82
83 if (update_allocation_history) {
84 // Average the fraction of eden allocated in a tlab by this
85 // thread for use in the next resize operation.
86 // _gc_waste is not subtracted because it's included in
87 // "used".
88 // The result can be larger than 1.0 due to direct to old allocations.
89 // These allocations should ideally not be counted but since it is not possible
90 // to filter them out here we just cap the fraction to be at most 1.0.
91 double alloc_frac = MIN2(1.0, (double) allocated_since_last_gc / used);
92 _allocation_fraction.sample(alloc_frac);
93 }
94 global_stats()->update_allocating_threads();
95 global_stats()->update_number_of_refills(_number_of_refills);
96 global_stats()->update_allocation(_number_of_refills * desired_size());
97 global_stats()->update_gc_waste(_gc_waste);
98 global_stats()->update_slow_refill_waste(_slow_refill_waste);
99 global_stats()->update_fast_refill_waste(_fast_refill_waste);
100
101 } else {
102 assert(_number_of_refills == 0 && _fast_refill_waste == 0 &&
103 _slow_refill_waste == 0 && _gc_waste == 0,
104 "tlab stats == 0");
105 }
106 global_stats()->update_slow_allocations(_slow_allocations);
107 }
108
109 // Fills the current tlab with a dummy filler array to create
110 // an illusion of a contiguous Eden and optionally retires the tlab.
111 // Waste accounting should be done in caller as appropriate; see,
112 // for example, clear_before_allocation().
113 void ThreadLocalAllocBuffer::make_parsable(bool retire) {
114 if (end() != NULL) {
115 invariants();
116
117 if (retire) {
118 myThread()->incr_allocated_bytes(used_bytes());
119 }
120
121 CollectedHeap::fill_with_object(top(), hard_end(), retire);
122
123 if (retire || ZeroTLAB) { // "Reset" the TLAB
124 set_start(NULL);
125 set_top(NULL);
126 set_pf_top(NULL);
127 set_end(NULL);
128 }
129 }
130 assert(!(retire || ZeroTLAB) ||
131 (start() == NULL && end() == NULL && top() == NULL),
132 "TLAB must be reset");
133 }
134
135 void ThreadLocalAllocBuffer::resize_all_tlabs() {
136 if (ResizeTLAB) {
137 for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) {
138 thread->tlab().resize();
139 }
140 }
141 }
142
143 void ThreadLocalAllocBuffer::resize() {
144 // Compute the next tlab size using expected allocation amount
145 assert(ResizeTLAB, "Should not call this otherwise");
146 size_t alloc = (size_t)(_allocation_fraction.average() *
147 (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize));
148 size_t new_size = alloc / _target_refills;
149
150 new_size = MIN2(MAX2(new_size, min_size()), max_size());
151
152 size_t aligned_new_size = align_object_size(new_size);
153
154 if (PrintTLAB && Verbose) {
155 gclog_or_tty->print("TLAB new size: thread: " INTPTR_FORMAT " [id: %2d]"
156 " refills %d alloc: %8.6f desired_size: " SIZE_FORMAT " -> " SIZE_FORMAT "\n",
157 myThread(), myThread()->osthread()->thread_id(),
158 _target_refills, _allocation_fraction.average(), desired_size(), aligned_new_size);
159 }
160 set_desired_size(aligned_new_size);
161 set_refill_waste_limit(initial_refill_waste_limit());
162 }
163
164 void ThreadLocalAllocBuffer::initialize_statistics() {
165 _number_of_refills = 0;
166 _fast_refill_waste = 0;
167 _slow_refill_waste = 0;
168 _gc_waste = 0;
169 _slow_allocations = 0;
170 }
171
172 void ThreadLocalAllocBuffer::fill(HeapWord* start,
173 HeapWord* top,
174 size_t new_size) {
175 _number_of_refills++;
176 if (PrintTLAB && Verbose) {
177 print_stats("fill");
178 }
179 assert(top <= start + new_size - alignment_reserve(), "size too small");
180 initialize(start, top, start + new_size - alignment_reserve());
181
182 // Reset amount of internal fragmentation
183 set_refill_waste_limit(initial_refill_waste_limit());
184 }
185
186 void ThreadLocalAllocBuffer::initialize(HeapWord* start,
187 HeapWord* top,
188 HeapWord* end) {
189 set_start(start);
190 set_top(top);
191 set_pf_top(top);
192 set_end(end);
193 invariants();
194 }
195
196 void ThreadLocalAllocBuffer::initialize() {
197 initialize(NULL, // start
198 NULL, // top
199 NULL); // end
200
201 set_desired_size(initial_desired_size());
202
203 // Following check is needed because at startup the main (primordial)
204 // thread is initialized before the heap is. The initialization for
205 // this thread is redone in startup_initialization below.
206 if (Universe::heap() != NULL) {
207 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize;
208 double alloc_frac = desired_size() * target_refills() / (double) capacity;
209 _allocation_fraction.sample(alloc_frac);
210 }
211
212 set_refill_waste_limit(initial_refill_waste_limit());
213
214 initialize_statistics();
215 }
216
217 void ThreadLocalAllocBuffer::startup_initialization() {
218
219 // Assuming each thread's active tlab is, on average,
220 // 1/2 full at a GC
221 _target_refills = 100 / (2 * TLABWasteTargetPercent);
222 _target_refills = MAX2(_target_refills, (unsigned)1U);
223
224 _global_stats = new GlobalTLABStats();
225
226 // During jvm startup, the main (primordial) thread is initialized
227 // before the heap is initialized. So reinitialize it now.
228 guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread");
229 Thread::current()->tlab().initialize();
230
231 if (PrintTLAB && Verbose) {
232 gclog_or_tty->print("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT "\n",
233 min_size(), Thread::current()->tlab().initial_desired_size(), max_size());
234 }
235 }
236
237 size_t ThreadLocalAllocBuffer::initial_desired_size() {
238 size_t init_sz;
239
240 if (TLABSize > 0) {
241 init_sz = MIN2((size_t)(TLABSize / HeapWordSize), max_size());
242 } else if (global_stats() == NULL) {
243 // Startup issue - main thread initialized before heap initialized.
244 init_sz = min_size();
245 } else {
246 // Initial size is a function of the average number of allocating threads.
247 unsigned nof_threads = global_stats()->allocating_threads_avg();
248
249 init_sz = (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize) /
250 (nof_threads * target_refills());
251 init_sz = align_object_size(init_sz);
252 init_sz = MIN2(MAX2(init_sz, min_size()), max_size());
253 }
254 return init_sz;
255 }
256
257 void ThreadLocalAllocBuffer::print_stats(const char* tag) {
258 Thread* thrd = myThread();
259 size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste;
260 size_t alloc = _number_of_refills * _desired_size;
261 double waste_percent = alloc == 0 ? 0.0 :
262 100.0 * waste / alloc;
263 size_t tlab_used = Universe::heap()->tlab_used(thrd);
264 gclog_or_tty->print("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]"
265 " desired_size: " SIZE_FORMAT "KB"
266 " slow allocs: %d refill waste: " SIZE_FORMAT "B"
267 " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB"
268 " slow: %dB fast: %dB\n",
269 tag, thrd, thrd->osthread()->thread_id(),
270 _desired_size / (K / HeapWordSize),
271 _slow_allocations, _refill_waste_limit * HeapWordSize,
272 _allocation_fraction.average(),
273 _allocation_fraction.average() * tlab_used / K,
274 _number_of_refills, waste_percent,
275 _gc_waste * HeapWordSize,
276 _slow_refill_waste * HeapWordSize,
277 _fast_refill_waste * HeapWordSize);
278 }
279
280 void ThreadLocalAllocBuffer::verify() {
281 HeapWord* p = start();
282 HeapWord* t = top();
283 HeapWord* prev_p = NULL;
284 while (p < t) {
285 oop(p)->verify();
286 prev_p = p;
287 p += oop(p)->size();
288 }
289 guarantee(p == top(), "end of last object must match end of space");
290 }
291
292 Thread* ThreadLocalAllocBuffer::myThread() {
293 return (Thread*)(((char *)this) +
294 in_bytes(start_offset()) -
295 in_bytes(Thread::tlab_start_offset()));
296 }
297
298
299 GlobalTLABStats::GlobalTLABStats() :
300 _allocating_threads_avg(TLABAllocationWeight) {
301
302 initialize();
303
304 _allocating_threads_avg.sample(1); // One allocating thread at startup
305
306 if (UsePerfData) {
307
308 EXCEPTION_MARK;
309 ResourceMark rm;
310
311 char* cname = PerfDataManager::counter_name("tlab", "allocThreads");
312 _perf_allocating_threads =
313 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
314
315 cname = PerfDataManager::counter_name("tlab", "fills");
316 _perf_total_refills =
317 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
318
319 cname = PerfDataManager::counter_name("tlab", "maxFills");
320 _perf_max_refills =
321 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
322
323 cname = PerfDataManager::counter_name("tlab", "alloc");
324 _perf_allocation =
325 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
326
327 cname = PerfDataManager::counter_name("tlab", "gcWaste");
328 _perf_gc_waste =
329 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
330
331 cname = PerfDataManager::counter_name("tlab", "maxGcWaste");
332 _perf_max_gc_waste =
333 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
334
335 cname = PerfDataManager::counter_name("tlab", "slowWaste");
336 _perf_slow_refill_waste =
337 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
338
339 cname = PerfDataManager::counter_name("tlab", "maxSlowWaste");
340 _perf_max_slow_refill_waste =
341 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
342
343 cname = PerfDataManager::counter_name("tlab", "fastWaste");
344 _perf_fast_refill_waste =
345 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
346
347 cname = PerfDataManager::counter_name("tlab", "maxFastWaste");
348 _perf_max_fast_refill_waste =
349 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
350
351 cname = PerfDataManager::counter_name("tlab", "slowAlloc");
352 _perf_slow_allocations =
353 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
354
355 cname = PerfDataManager::counter_name("tlab", "maxSlowAlloc");
356 _perf_max_slow_allocations =
357 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
358 }
359 }
360
361 void GlobalTLABStats::initialize() {
362 // Clear counters summarizing info from all threads
363 _allocating_threads = 0;
364 _total_refills = 0;
365 _max_refills = 0;
366 _total_allocation = 0;
367 _total_gc_waste = 0;
368 _max_gc_waste = 0;
369 _total_slow_refill_waste = 0;
370 _max_slow_refill_waste = 0;
371 _total_fast_refill_waste = 0;
372 _max_fast_refill_waste = 0;
373 _total_slow_allocations = 0;
374 _max_slow_allocations = 0;
375 }
376
377 void GlobalTLABStats::publish() {
378 _allocating_threads_avg.sample(_allocating_threads);
379 if (UsePerfData) {
380 _perf_allocating_threads ->set_value(_allocating_threads);
381 _perf_total_refills ->set_value(_total_refills);
382 _perf_max_refills ->set_value(_max_refills);
383 _perf_allocation ->set_value(_total_allocation);
384 _perf_gc_waste ->set_value(_total_gc_waste);
385 _perf_max_gc_waste ->set_value(_max_gc_waste);
386 _perf_slow_refill_waste ->set_value(_total_slow_refill_waste);
387 _perf_max_slow_refill_waste->set_value(_max_slow_refill_waste);
388 _perf_fast_refill_waste ->set_value(_total_fast_refill_waste);
389 _perf_max_fast_refill_waste->set_value(_max_fast_refill_waste);
390 _perf_slow_allocations ->set_value(_total_slow_allocations);
391 _perf_max_slow_allocations ->set_value(_max_slow_allocations);
392 }
393 }
394
395 void GlobalTLABStats::print() {
396 size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste;
397 double waste_percent = _total_allocation == 0 ? 0.0 :
398 100.0 * waste / _total_allocation;
399 gclog_or_tty->print("TLAB totals: thrds: %d refills: %d max: %d"
400 " slow allocs: %d max %d waste: %4.1f%%"
401 " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"
402 " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"
403 " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B\n",
404 _allocating_threads,
405 _total_refills, _max_refills,
406 _total_slow_allocations, _max_slow_allocations,
407 waste_percent,
408 _total_gc_waste * HeapWordSize,
409 _max_gc_waste * HeapWordSize,
410 _total_slow_refill_waste * HeapWordSize,
411 _max_slow_refill_waste * HeapWordSize,
412 _total_fast_refill_waste * HeapWordSize,
413 _max_fast_refill_waste * HeapWordSize);
414 }