1 /* 2 * Copyright (c) 1999, 2018, 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 "gc/shared/threadLocalAllocBuffer.inline.hpp" 27 #include "logging/log.hpp" 28 #include "memory/resourceArea.hpp" 29 #include "memory/universe.hpp" 30 #include "oops/oop.inline.hpp" 31 #include "runtime/thread.inline.hpp" 32 #include "runtime/threadSMR.hpp" 33 #include "utilities/copy.hpp" 34 35 size_t ThreadLocalAllocBuffer::_max_size = 0; 36 int ThreadLocalAllocBuffer::_reserve_for_allocation_prefetch = 0; 37 unsigned int ThreadLocalAllocBuffer::_target_refills = 0; 38 39 size_t ThreadLocalAllocBuffer::remaining() { 40 if (end() == NULL) { 41 return 0; 42 } 43 44 return pointer_delta(hard_end(), top()); 45 } 46 47 void ThreadLocalAllocBuffer::accumulate_and_reset_statistics(ThreadLocalAllocStats* stats) { 48 Thread* thr = thread(); 49 size_t capacity = Universe::heap()->tlab_capacity(thr); 50 size_t used = Universe::heap()->tlab_used(thr); 51 52 _gc_waste += (unsigned)remaining(); 53 size_t total_allocated = thr->allocated_bytes(); 54 size_t allocated_since_last_gc = total_allocated - _allocated_before_last_gc; 55 _allocated_before_last_gc = total_allocated; 56 57 print_stats("gc"); 58 59 if (_number_of_refills > 0) { 60 // Update allocation history if a reasonable amount of eden was allocated. 61 bool update_allocation_history = used > 0.5 * capacity; 62 63 if (update_allocation_history) { 64 // Average the fraction of eden allocated in a tlab by this 65 // thread for use in the next resize operation. 66 // _gc_waste is not subtracted because it's included in 67 // "used". 68 // The result can be larger than 1.0 due to direct to old allocations. 69 // These allocations should ideally not be counted but since it is not possible 70 // to filter them out here we just cap the fraction to be at most 1.0. 71 double alloc_frac = MIN2(1.0, (double) allocated_since_last_gc / used); 72 _allocation_fraction.sample(alloc_frac); 73 } 74 75 stats->update_fast_allocations(_number_of_refills, 76 _allocated_size, 77 _gc_waste, 78 _fast_refill_waste, 79 _slow_refill_waste); 80 } else { 81 assert(_number_of_refills == 0 && _fast_refill_waste == 0 && 82 _slow_refill_waste == 0 && _gc_waste == 0, 83 "tlab stats == 0"); 84 } 85 86 stats->update_slow_allocations(_slow_allocations); 87 88 reset_statistics(); 89 } 90 91 void ThreadLocalAllocBuffer::insert_filler() { 92 assert(end() != NULL, "Must not be retired"); 93 Universe::heap()->fill_with_dummy_object(top(), hard_end(), true); 94 } 95 96 void ThreadLocalAllocBuffer::make_parsable() { 97 if (end() != NULL) { 98 invariants(); 99 if (ZeroTLAB) { 100 retire(); 101 } else { 102 insert_filler(); 103 } 104 } 105 } 106 107 void ThreadLocalAllocBuffer::retire(ThreadLocalAllocStats* stats) { 108 if (stats != NULL) { 109 accumulate_and_reset_statistics(stats); 110 } 111 112 if (end() != NULL) { 113 invariants(); 114 thread()->incr_allocated_bytes(used_bytes()); 115 insert_filler(); 116 initialize(NULL, NULL, NULL); 117 } 118 } 119 120 void ThreadLocalAllocBuffer::retire_before_allocation() { 121 _slow_refill_waste += (unsigned int)remaining(); 122 retire(); 123 } 124 125 void ThreadLocalAllocBuffer::resize() { 126 // Compute the next tlab size using expected allocation amount 127 assert(ResizeTLAB, "Should not call this otherwise"); 128 size_t alloc = (size_t)(_allocation_fraction.average() * 129 (Universe::heap()->tlab_capacity(thread()) / 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 log_trace(gc, tlab)("TLAB new size: thread: " INTPTR_FORMAT " [id: %2d]" 137 " refills %d alloc: %8.6f desired_size: " SIZE_FORMAT " -> " SIZE_FORMAT, 138 p2i(thread()), thread()->osthread()->thread_id(), 139 _target_refills, _allocation_fraction.average(), desired_size(), aligned_new_size); 140 141 set_desired_size(aligned_new_size); 142 set_refill_waste_limit(initial_refill_waste_limit()); 143 } 144 145 void ThreadLocalAllocBuffer::reset_statistics() { 146 _number_of_refills = 0; 147 _fast_refill_waste = 0; 148 _slow_refill_waste = 0; 149 _gc_waste = 0; 150 _slow_allocations = 0; 151 _allocated_size = 0; 152 } 153 154 void ThreadLocalAllocBuffer::fill(HeapWord* start, 155 HeapWord* top, 156 size_t new_size) { 157 _number_of_refills++; 158 _allocated_size += new_size; 159 print_stats("fill"); 160 assert(top <= start + new_size - alignment_reserve(), "size too small"); 161 162 initialize(start, top, start + new_size - alignment_reserve()); 163 164 // Reset amount of internal fragmentation 165 set_refill_waste_limit(initial_refill_waste_limit()); 166 } 167 168 void ThreadLocalAllocBuffer::initialize(HeapWord* start, 169 HeapWord* top, 170 HeapWord* end) { 171 set_start(start); 172 set_top(top); 173 set_pf_top(top); 174 set_end(end); 175 set_allocation_end(end); 176 invariants(); 177 } 178 179 void ThreadLocalAllocBuffer::initialize() { 180 initialize(NULL, // start 181 NULL, // top 182 NULL); // end 183 184 set_desired_size(initial_desired_size()); 185 186 size_t capacity = Universe::heap()->tlab_capacity(thread()) / HeapWordSize; 187 double alloc_frac = desired_size() * target_refills() / (double) capacity; 188 _allocation_fraction.sample(alloc_frac); 189 190 set_refill_waste_limit(initial_refill_waste_limit()); 191 192 reset_statistics(); 193 } 194 195 void ThreadLocalAllocBuffer::startup_initialization() { 196 ThreadLocalAllocStats::initialize(); 197 198 // Assuming each thread's active tlab is, on average, 199 // 1/2 full at a GC 200 _target_refills = 100 / (2 * TLABWasteTargetPercent); 201 // We need to set initial target refills to 2 to avoid a GC which causes VM 202 // abort during VM initialization. 203 _target_refills = MAX2(_target_refills, 2U); 204 205 #ifdef COMPILER2 206 // If the C2 compiler is present, extra space is needed at the end of 207 // TLABs, otherwise prefetching instructions generated by the C2 208 // compiler will fault (due to accessing memory outside of heap). 209 // The amount of space is the max of the number of lines to 210 // prefetch for array and for instance allocations. (Extra space must be 211 // reserved to accommodate both types of allocations.) 212 // 213 // Only SPARC-specific BIS instructions are known to fault. (Those 214 // instructions are generated if AllocatePrefetchStyle==3 and 215 // AllocatePrefetchInstr==1). To be on the safe side, however, 216 // extra space is reserved for all combinations of 217 // AllocatePrefetchStyle and AllocatePrefetchInstr. 218 // 219 // If the C2 compiler is not present, no space is reserved. 220 221 // +1 for rounding up to next cache line, +1 to be safe 222 if (is_server_compilation_mode_vm()) { 223 int lines = MAX2(AllocatePrefetchLines, AllocateInstancePrefetchLines) + 2; 224 _reserve_for_allocation_prefetch = (AllocatePrefetchDistance + AllocatePrefetchStepSize * lines) / 225 (int)HeapWordSize; 226 } 227 #endif 228 229 // During jvm startup, the main thread is initialized 230 // before the heap is initialized. So reinitialize it now. 231 guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread"); 232 Thread::current()->tlab().initialize(); 233 234 log_develop_trace(gc, tlab)("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT, 235 min_size(), Thread::current()->tlab().initial_desired_size(), max_size()); 236 } 237 238 size_t ThreadLocalAllocBuffer::initial_desired_size() { 239 size_t init_sz = 0; 240 241 if (TLABSize > 0) { 242 init_sz = TLABSize / HeapWordSize; 243 } else { 244 // Initial size is a function of the average number of allocating threads. 245 unsigned int nof_threads = ThreadLocalAllocStats::allocating_threads_avg(); 246 247 init_sz = (Universe::heap()->tlab_capacity(thread()) / HeapWordSize) / 248 (nof_threads * target_refills()); 249 init_sz = align_object_size(init_sz); 250 } 251 init_sz = MIN2(MAX2(init_sz, min_size()), max_size()); 252 return init_sz; 253 } 254 255 void ThreadLocalAllocBuffer::print_stats(const char* tag) { 256 Log(gc, tlab) log; 257 if (!log.is_trace()) { 258 return; 259 } 260 261 Thread* thrd = thread(); 262 size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste; 263 double waste_percent = percent_of(waste, _allocated_size); 264 size_t tlab_used = Universe::heap()->tlab_used(thrd); 265 log.trace("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]" 266 " desired_size: " SIZE_FORMAT "KB" 267 " slow allocs: %d refill waste: " SIZE_FORMAT "B" 268 " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB" 269 " slow: %dB fast: %dB", 270 tag, p2i(thrd), thrd->osthread()->thread_id(), 271 _desired_size / (K / HeapWordSize), 272 _slow_allocations, _refill_waste_limit * HeapWordSize, 273 _allocation_fraction.average(), 274 _allocation_fraction.average() * tlab_used / K, 275 _number_of_refills, waste_percent, 276 _gc_waste * HeapWordSize, 277 _slow_refill_waste * HeapWordSize, 278 _fast_refill_waste * HeapWordSize); 279 } 280 281 void ThreadLocalAllocBuffer::verify() { 282 HeapWord* p = start(); 283 HeapWord* t = top(); 284 HeapWord* prev_p = NULL; 285 while (p < t) { 286 oopDesc::verify(oop(p)); 287 prev_p = p; 288 p += oop(p)->size(); 289 } 290 guarantee(p == top(), "end of last object must match end of space"); 291 } 292 293 void ThreadLocalAllocBuffer::set_sample_end() { 294 size_t heap_words_remaining = pointer_delta(_end, _top); 295 size_t bytes_until_sample = thread()->heap_sampler().bytes_until_sample(); 296 size_t words_until_sample = bytes_until_sample / HeapWordSize; 297 298 if (heap_words_remaining > words_until_sample) { 299 HeapWord* new_end = _top + words_until_sample; 300 set_end(new_end); 301 _bytes_since_last_sample_point = bytes_until_sample; 302 } else { 303 _bytes_since_last_sample_point = heap_words_remaining * HeapWordSize; 304 } 305 } 306 307 Thread* ThreadLocalAllocBuffer::thread() { 308 return (Thread*)(((char*)this) + in_bytes(start_offset()) - in_bytes(Thread::tlab_start_offset())); 309 } 310 311 void ThreadLocalAllocBuffer::set_back_allocation_end() { 312 _end = _allocation_end; 313 } 314 315 HeapWord* ThreadLocalAllocBuffer::hard_end() { 316 return _allocation_end + alignment_reserve(); 317 } 318 319 PerfVariable* ThreadLocalAllocStats::_perf_allocating_threads; 320 PerfVariable* ThreadLocalAllocStats::_perf_total_refills; 321 PerfVariable* ThreadLocalAllocStats::_perf_max_refills; 322 PerfVariable* ThreadLocalAllocStats::_perf_total_allocations; 323 PerfVariable* ThreadLocalAllocStats::_perf_total_gc_waste; 324 PerfVariable* ThreadLocalAllocStats::_perf_max_gc_waste; 325 PerfVariable* ThreadLocalAllocStats::_perf_total_slow_refill_waste; 326 PerfVariable* ThreadLocalAllocStats::_perf_max_slow_refill_waste; 327 PerfVariable* ThreadLocalAllocStats::_perf_total_fast_refill_waste; 328 PerfVariable* ThreadLocalAllocStats::_perf_max_fast_refill_waste; 329 PerfVariable* ThreadLocalAllocStats::_perf_total_slow_allocations; 330 PerfVariable* ThreadLocalAllocStats::_perf_max_slow_allocations; 331 AdaptiveWeightedAverage ThreadLocalAllocStats::_allocating_threads_avg(0); 332 333 static PerfVariable* create_perf_variable(const char* name, PerfData::Units unit, TRAPS) { 334 ResourceMark rm; 335 return PerfDataManager::create_variable(SUN_GC, PerfDataManager::counter_name("tlab", name), unit, THREAD); 336 } 337 338 void ThreadLocalAllocStats::initialize() { 339 _allocating_threads_avg = AdaptiveWeightedAverage(TLABAllocationWeight); 340 _allocating_threads_avg.sample(1); // One allocating thread at startup 341 342 if (UsePerfData) { 343 EXCEPTION_MARK; 344 _perf_allocating_threads = create_perf_variable("allocThreads", PerfData::U_None, CHECK); 345 _perf_total_refills = create_perf_variable("fills", PerfData::U_None, CHECK); 346 _perf_max_refills = create_perf_variable("maxFills", PerfData::U_None, CHECK); 347 _perf_total_allocations = create_perf_variable("alloc", PerfData::U_Bytes, CHECK); 348 _perf_total_gc_waste = create_perf_variable("gcWaste", PerfData::U_Bytes, CHECK); 349 _perf_max_gc_waste = create_perf_variable("maxGcWaste", PerfData::U_Bytes, CHECK); 350 _perf_total_slow_refill_waste = create_perf_variable("slowWaste", PerfData::U_Bytes, CHECK); 351 _perf_max_slow_refill_waste = create_perf_variable("maxSlowWaste", PerfData::U_Bytes, CHECK); 352 _perf_total_fast_refill_waste = create_perf_variable("fastWaste", PerfData::U_Bytes, CHECK); 353 _perf_max_fast_refill_waste = create_perf_variable("maxFastWaste", PerfData::U_Bytes, CHECK); 354 _perf_total_slow_allocations = create_perf_variable("slowAlloc", PerfData::U_None, CHECK); 355 _perf_max_slow_allocations = create_perf_variable("maxSlowAlloc", PerfData::U_None, CHECK); 356 } 357 } 358 359 ThreadLocalAllocStats::ThreadLocalAllocStats() : 360 _allocating_threads(0), 361 _total_refills(0), 362 _max_refills(0), 363 _total_allocations(0), 364 _total_gc_waste(0), 365 _max_gc_waste(0), 366 _total_fast_refill_waste(0), 367 _max_fast_refill_waste(0), 368 _total_slow_refill_waste(0), 369 _max_slow_refill_waste(0), 370 _total_slow_allocations(0), 371 _max_slow_allocations(0) {} 372 373 unsigned int ThreadLocalAllocStats::allocating_threads_avg() { 374 return MAX2((unsigned int)(_allocating_threads_avg.average() + 0.5), 1U); 375 } 376 377 void ThreadLocalAllocStats::update_fast_allocations(unsigned int refills, 378 size_t allocations, 379 size_t gc_waste, 380 size_t fast_refill_waste, 381 size_t slow_refill_waste) { 382 _allocating_threads += 1; 383 _total_refills += refills; 384 _max_refills = MAX2(_max_refills, refills); 385 _total_allocations += allocations; 386 _total_gc_waste += gc_waste; 387 _max_gc_waste = MAX2(_max_gc_waste, gc_waste); 388 _total_fast_refill_waste += fast_refill_waste; 389 _max_fast_refill_waste = MAX2(_max_fast_refill_waste, fast_refill_waste); 390 _total_slow_refill_waste += slow_refill_waste; 391 _max_slow_refill_waste = MAX2(_max_slow_refill_waste, slow_refill_waste); 392 } 393 394 void ThreadLocalAllocStats::update_slow_allocations(unsigned int allocations) { 395 _total_slow_allocations += allocations; 396 _max_slow_allocations = MAX2(_max_slow_allocations, allocations); 397 } 398 399 void ThreadLocalAllocStats::update(const ThreadLocalAllocStats& other) { 400 _allocating_threads += other._allocating_threads; 401 _total_refills += other._total_refills; 402 _max_refills = MAX2(_max_refills, other._max_refills); 403 _total_allocations += other._total_allocations; 404 _total_gc_waste += other._total_gc_waste; 405 _max_gc_waste = MAX2(_max_gc_waste, other._max_gc_waste); 406 _total_fast_refill_waste += other._total_fast_refill_waste; 407 _max_fast_refill_waste = MAX2(_max_fast_refill_waste, other._max_fast_refill_waste); 408 _total_slow_refill_waste += other._total_slow_refill_waste; 409 _max_slow_refill_waste = MAX2(_max_slow_refill_waste, other._max_slow_refill_waste); 410 _total_slow_allocations += other._total_slow_allocations; 411 _max_slow_allocations = MAX2(_max_slow_allocations, other._max_slow_allocations); 412 } 413 414 void ThreadLocalAllocStats::reset() { 415 _allocating_threads = 0; 416 _total_refills = 0; 417 _max_refills = 0; 418 _total_allocations = 0; 419 _total_gc_waste = 0; 420 _max_gc_waste = 0; 421 _total_fast_refill_waste = 0; 422 _max_fast_refill_waste = 0; 423 _total_slow_refill_waste = 0; 424 _max_slow_refill_waste = 0; 425 _total_slow_allocations = 0; 426 _max_slow_allocations = 0; 427 } 428 429 void ThreadLocalAllocStats::publish() { 430 if (_total_allocations == 0) { 431 return; 432 } 433 434 _allocating_threads_avg.sample(_allocating_threads); 435 436 const size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste; 437 const double waste_percent = percent_of(waste, _total_allocations); 438 log_debug(gc, tlab)("TLAB totals: thrds: %d refills: %d max: %d" 439 " slow allocs: %d max %d waste: %4.1f%%" 440 " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" 441 " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" 442 " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B", 443 _allocating_threads, _total_refills, _max_refills, 444 _total_slow_allocations, _max_slow_allocations, waste_percent, 445 _total_gc_waste * HeapWordSize, _max_gc_waste * HeapWordSize, 446 _total_slow_refill_waste * HeapWordSize, _max_slow_refill_waste * HeapWordSize, 447 _total_fast_refill_waste * HeapWordSize, _max_fast_refill_waste * HeapWordSize); 448 449 if (UsePerfData) { 450 _perf_allocating_threads ->set_value(_allocating_threads); 451 _perf_total_refills ->set_value(_total_refills); 452 _perf_max_refills ->set_value(_max_refills); 453 _perf_total_allocations ->set_value(_total_allocations); 454 _perf_total_gc_waste ->set_value(_total_gc_waste); 455 _perf_max_gc_waste ->set_value(_max_gc_waste); 456 _perf_total_slow_refill_waste ->set_value(_total_slow_refill_waste); 457 _perf_max_slow_refill_waste ->set_value(_max_slow_refill_waste); 458 _perf_total_fast_refill_waste ->set_value(_total_fast_refill_waste); 459 _perf_max_fast_refill_waste ->set_value(_max_fast_refill_waste); 460 _perf_total_slow_allocations ->set_value(_total_slow_allocations); 461 _perf_max_slow_allocations ->set_value(_max_slow_allocations); 462 } 463 }