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comparison src/share/vm/memory/threadLocalAllocBuffer.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 1999-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 // Thread-Local Edens support
26
27 # include "incls/_precompiled.incl"
28 # include "incls/_threadLocalAllocBuffer.cpp.incl"
29
30 // static member initialization
31 unsigned ThreadLocalAllocBuffer::_target_refills = 0;
32 GlobalTLABStats* ThreadLocalAllocBuffer::_global_stats = NULL;
33
34 void ThreadLocalAllocBuffer::clear_before_allocation() {
35 _slow_refill_waste += (unsigned)remaining();
36 make_parsable(true); // also retire the TLAB
37 }
38
39 void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() {
40 global_stats()->initialize();
41
42 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
43 thread->tlab().accumulate_statistics();
44 thread->tlab().initialize_statistics();
45 }
46
47 // Publish new stats if some allocation occurred.
48 if (global_stats()->allocation() != 0) {
49 global_stats()->publish();
50 if (PrintTLAB) {
51 global_stats()->print();
52 }
53 }
54 }
55
56 void ThreadLocalAllocBuffer::accumulate_statistics() {
57 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize;
58 size_t unused = Universe::heap()->unsafe_max_tlab_alloc(myThread()) / HeapWordSize;
59 size_t used = capacity - unused;
60
61 // Update allocation history if a reasonable amount of eden was allocated.
62 bool update_allocation_history = used > 0.5 * capacity;
63
64 _gc_waste += (unsigned)remaining();
65
66 if (PrintTLAB && (_number_of_refills > 0 || Verbose)) {
67 print_stats("gc");
68 }
69
70 if (_number_of_refills > 0) {
71
72 if (update_allocation_history) {
73 // Average the fraction of eden allocated in a tlab by this
74 // thread for use in the next resize operation.
75 // _gc_waste is not subtracted because it's included in
76 // "used".
77 size_t allocation = _number_of_refills * desired_size();
78 double alloc_frac = allocation / (double) used;
79 _allocation_fraction.sample(alloc_frac);
80 }
81 global_stats()->update_allocating_threads();
82 global_stats()->update_number_of_refills(_number_of_refills);
83 global_stats()->update_allocation(_number_of_refills * desired_size());
84 global_stats()->update_gc_waste(_gc_waste);
85 global_stats()->update_slow_refill_waste(_slow_refill_waste);
86 global_stats()->update_fast_refill_waste(_fast_refill_waste);
87
88 } else {
89 assert(_number_of_refills == 0 && _fast_refill_waste == 0 &&
90 _slow_refill_waste == 0 && _gc_waste == 0,
91 "tlab stats == 0");
92 }
93 global_stats()->update_slow_allocations(_slow_allocations);
94 }
95
96 // Fills the current tlab with a dummy filler array to create
97 // an illusion of a contiguous Eden and optionally retires the tlab.
98 // Waste accounting should be done in caller as appropriate; see,
99 // for example, clear_before_allocation().
100 void ThreadLocalAllocBuffer::make_parsable(bool retire) {
101 if (end() != NULL) {
102 invariants();
103 MemRegion mr(top(), hard_end());
104 SharedHeap::fill_region_with_object(mr);
105
106 if (retire || ZeroTLAB) { // "Reset" the TLAB
107 set_start(NULL);
108 set_top(NULL);
109 set_pf_top(NULL);
110 set_end(NULL);
111 }
112 }
113 assert(!(retire || ZeroTLAB) ||
114 (start() == NULL && end() == NULL && top() == NULL),
115 "TLAB must be reset");
116 }
117
118 void ThreadLocalAllocBuffer::resize_all_tlabs() {
119 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
120 thread->tlab().resize();
121 }
122 }
123
124 void ThreadLocalAllocBuffer::resize() {
125
126 if (ResizeTLAB) {
127 // Compute the next tlab size using expected allocation amount
128 size_t alloc = (size_t)(_allocation_fraction.average() *
129 (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize));
130 size_t new_size = alloc / _target_refills;
131
132 new_size = MIN2(MAX2(new_size, min_size()), max_size());
133
134 size_t aligned_new_size = align_object_size(new_size);
135
136 if (PrintTLAB && Verbose) {
137 gclog_or_tty->print("TLAB new size: thread: " INTPTR_FORMAT " [id: %2d]"
138 " refills %d alloc: %8.6f desired_size: " SIZE_FORMAT " -> " SIZE_FORMAT "\n",
139 myThread(), myThread()->osthread()->thread_id(),
140 _target_refills, _allocation_fraction.average(), desired_size(), aligned_new_size);
141 }
142 set_desired_size(aligned_new_size);
143
144 set_refill_waste_limit(initial_refill_waste_limit());
145 }
146 }
147
148 void ThreadLocalAllocBuffer::initialize_statistics() {
149 _number_of_refills = 0;
150 _fast_refill_waste = 0;
151 _slow_refill_waste = 0;
152 _gc_waste = 0;
153 _slow_allocations = 0;
154 }
155
156 void ThreadLocalAllocBuffer::fill(HeapWord* start,
157 HeapWord* top,
158 size_t new_size) {
159 _number_of_refills++;
160 if (PrintTLAB && Verbose) {
161 print_stats("fill");
162 }
163 assert(top <= start + new_size - alignment_reserve(), "size too small");
164 initialize(start, top, start + new_size - alignment_reserve());
165
166 // Reset amount of internal fragmentation
167 set_refill_waste_limit(initial_refill_waste_limit());
168 }
169
170 void ThreadLocalAllocBuffer::initialize(HeapWord* start,
171 HeapWord* top,
172 HeapWord* end) {
173 set_start(start);
174 set_top(top);
175 set_pf_top(top);
176 set_end(end);
177 invariants();
178 }
179
180 void ThreadLocalAllocBuffer::initialize() {
181 initialize(NULL, // start
182 NULL, // top
183 NULL); // end
184
185 set_desired_size(initial_desired_size());
186
187 // Following check is needed because at startup the main (primordial)
188 // thread is initialized before the heap is. The initialization for
189 // this thread is redone in startup_initialization below.
190 if (Universe::heap() != NULL) {
191 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize;
192 double alloc_frac = desired_size() * target_refills() / (double) capacity;
193 _allocation_fraction.sample(alloc_frac);
194 }
195
196 set_refill_waste_limit(initial_refill_waste_limit());
197
198 initialize_statistics();
199 }
200
201 void ThreadLocalAllocBuffer::startup_initialization() {
202
203 // Assuming each thread's active tlab is, on average,
204 // 1/2 full at a GC
205 _target_refills = 100 / (2 * TLABWasteTargetPercent);
206 _target_refills = MAX2(_target_refills, (unsigned)1U);
207
208 _global_stats = new GlobalTLABStats();
209
210 // During jvm startup, the main (primordial) thread is initialized
211 // before the heap is initialized. So reinitialize it now.
212 guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread");
213 Thread::current()->tlab().initialize();
214
215 if (PrintTLAB && Verbose) {
216 gclog_or_tty->print("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT "\n",
217 min_size(), Thread::current()->tlab().initial_desired_size(), max_size());
218 }
219 }
220
221 size_t ThreadLocalAllocBuffer::initial_desired_size() {
222 size_t init_sz;
223
224 if (TLABSize > 0) {
225 init_sz = MIN2(TLABSize / HeapWordSize, max_size());
226 } else if (global_stats() == NULL) {
227 // Startup issue - main thread initialized before heap initialized.
228 init_sz = min_size();
229 } else {
230 // Initial size is a function of the average number of allocating threads.
231 unsigned nof_threads = global_stats()->allocating_threads_avg();
232
233 init_sz = (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize) /
234 (nof_threads * target_refills());
235 init_sz = align_object_size(init_sz);
236 init_sz = MIN2(MAX2(init_sz, min_size()), max_size());
237 }
238 return init_sz;
239 }
240
241 const size_t ThreadLocalAllocBuffer::max_size() {
242
243 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
244 // This restriction could be removed by enabling filling with multiple arrays.
245 // If we compute that the reasonable way as
246 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
247 // we'll overflow on the multiply, so we do the divide first.
248 // We actually lose a little by dividing first,
249 // but that just makes the TLAB somewhat smaller than the biggest array,
250 // which is fine, since we'll be able to fill that.
251
252 size_t unaligned_max_size = typeArrayOopDesc::header_size(T_INT) +
253 sizeof(jint) *
254 ((juint) max_jint / (size_t) HeapWordSize);
255 return align_size_down(unaligned_max_size, MinObjAlignment);
256 }
257
258 void ThreadLocalAllocBuffer::print_stats(const char* tag) {
259 Thread* thrd = myThread();
260 size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste;
261 size_t alloc = _number_of_refills * _desired_size;
262 double waste_percent = alloc == 0 ? 0.0 :
263 100.0 * waste / alloc;
264 size_t tlab_used = Universe::heap()->tlab_capacity(thrd) -
265 Universe::heap()->unsafe_max_tlab_alloc(thrd);
266 gclog_or_tty->print("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]"
267 " desired_size: " SIZE_FORMAT "KB"
268 " slow allocs: %d refill waste: " SIZE_FORMAT "B"
269 " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB"
270 " slow: %dB fast: %dB\n",
271 tag, thrd, thrd->osthread()->thread_id(),
272 _desired_size / (K / HeapWordSize),
273 _slow_allocations, _refill_waste_limit * HeapWordSize,
274 _allocation_fraction.average(),
275 _allocation_fraction.average() * tlab_used / K,
276 _number_of_refills, waste_percent,
277 _gc_waste * HeapWordSize,
278 _slow_refill_waste * HeapWordSize,
279 _fast_refill_waste * HeapWordSize);
280 }
281
282 void ThreadLocalAllocBuffer::verify() {
283 HeapWord* p = start();
284 HeapWord* t = top();
285 HeapWord* prev_p = NULL;
286 while (p < t) {
287 oop(p)->verify();
288 prev_p = p;
289 p += oop(p)->size();
290 }
291 guarantee(p == top(), "end of last object must match end of space");
292 }
293
294 Thread* ThreadLocalAllocBuffer::myThread() {
295 return (Thread*)(((char *)this) +
296 in_bytes(start_offset()) -
297 in_bytes(Thread::tlab_start_offset()));
298 }
299
300
301 GlobalTLABStats::GlobalTLABStats() :
302 _allocating_threads_avg(TLABAllocationWeight) {
303
304 initialize();
305
306 _allocating_threads_avg.sample(1); // One allocating thread at startup
307
308 if (UsePerfData) {
309
310 EXCEPTION_MARK;
311 ResourceMark rm;
312
313 char* cname = PerfDataManager::counter_name("tlab", "allocThreads");
314 _perf_allocating_threads =
315 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
316
317 cname = PerfDataManager::counter_name("tlab", "fills");
318 _perf_total_refills =
319 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
320
321 cname = PerfDataManager::counter_name("tlab", "maxFills");
322 _perf_max_refills =
323 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
324
325 cname = PerfDataManager::counter_name("tlab", "alloc");
326 _perf_allocation =
327 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
328
329 cname = PerfDataManager::counter_name("tlab", "gcWaste");
330 _perf_gc_waste =
331 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
332
333 cname = PerfDataManager::counter_name("tlab", "maxGcWaste");
334 _perf_max_gc_waste =
335 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
336
337 cname = PerfDataManager::counter_name("tlab", "slowWaste");
338 _perf_slow_refill_waste =
339 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
340
341 cname = PerfDataManager::counter_name("tlab", "maxSlowWaste");
342 _perf_max_slow_refill_waste =
343 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
344
345 cname = PerfDataManager::counter_name("tlab", "fastWaste");
346 _perf_fast_refill_waste =
347 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
348
349 cname = PerfDataManager::counter_name("tlab", "maxFastWaste");
350 _perf_max_fast_refill_waste =
351 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
352
353 cname = PerfDataManager::counter_name("tlab", "slowAlloc");
354 _perf_slow_allocations =
355 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
356
357 cname = PerfDataManager::counter_name("tlab", "maxSlowAlloc");
358 _perf_max_slow_allocations =
359 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
360 }
361 }
362
363 void GlobalTLABStats::initialize() {
364 // Clear counters summarizing info from all threads
365 _allocating_threads = 0;
366 _total_refills = 0;
367 _max_refills = 0;
368 _total_allocation = 0;
369 _total_gc_waste = 0;
370 _max_gc_waste = 0;
371 _total_slow_refill_waste = 0;
372 _max_slow_refill_waste = 0;
373 _total_fast_refill_waste = 0;
374 _max_fast_refill_waste = 0;
375 _total_slow_allocations = 0;
376 _max_slow_allocations = 0;
377 }
378
379 void GlobalTLABStats::publish() {
380 _allocating_threads_avg.sample(_allocating_threads);
381 if (UsePerfData) {
382 _perf_allocating_threads ->set_value(_allocating_threads);
383 _perf_total_refills ->set_value(_total_refills);
384 _perf_max_refills ->set_value(_max_refills);
385 _perf_allocation ->set_value(_total_allocation);
386 _perf_gc_waste ->set_value(_total_gc_waste);
387 _perf_max_gc_waste ->set_value(_max_gc_waste);
388 _perf_slow_refill_waste ->set_value(_total_slow_refill_waste);
389 _perf_max_slow_refill_waste->set_value(_max_slow_refill_waste);
390 _perf_fast_refill_waste ->set_value(_total_fast_refill_waste);
391 _perf_max_fast_refill_waste->set_value(_max_fast_refill_waste);
392 _perf_slow_allocations ->set_value(_total_slow_allocations);
393 _perf_max_slow_allocations ->set_value(_max_slow_allocations);
394 }
395 }
396
397 void GlobalTLABStats::print() {
398 size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste;
399 double waste_percent = _total_allocation == 0 ? 0.0 :
400 100.0 * waste / _total_allocation;
401 gclog_or_tty->print("TLAB totals: thrds: %d refills: %d max: %d"
402 " slow allocs: %d max %d waste: %4.1f%%"
403 " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"
404 " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"
405 " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B\n",
406 _allocating_threads,
407 _total_refills, _max_refills,
408 _total_slow_allocations, _max_slow_allocations,
409 waste_percent,
410 _total_gc_waste * HeapWordSize,
411 _max_gc_waste * HeapWordSize,
412 _total_slow_refill_waste * HeapWordSize,
413 _max_slow_refill_waste * HeapWordSize,
414 _total_fast_refill_waste * HeapWordSize,
415 _max_fast_refill_waste * HeapWordSize);
416 }