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 "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 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 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 = 0; 239 240 if (TLABSize > 0) { 241 init_sz = TLABSize / HeapWordSize; 242 } else if (global_stats() != NULL) { 243 // Initial size is a function of the average number of allocating threads. 244 unsigned nof_threads = global_stats()->allocating_threads_avg(); 245 246 init_sz = (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize) / 247 (nof_threads * target_refills()); 248 init_sz = align_object_size(init_sz); 249 } 250 init_sz = MIN2(MAX2(init_sz, min_size()), max_size()); 251 return init_sz; 252 } 253 254 void ThreadLocalAllocBuffer::print_stats(const char* tag) { 255 Thread* thrd = myThread(); 256 size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste; 257 size_t alloc = _number_of_refills * _desired_size; 258 double waste_percent = alloc == 0 ? 0.0 : 259 100.0 * waste / alloc; 260 size_t tlab_used = Universe::heap()->tlab_used(thrd); 261 gclog_or_tty->print("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]" 262 " desired_size: " SIZE_FORMAT "KB" 263 " slow allocs: %d refill waste: " SIZE_FORMAT "B" 264 " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB" 265 " slow: %dB fast: %dB\n", 266 tag, thrd, thrd->osthread()->thread_id(), 267 _desired_size / (K / HeapWordSize), 268 _slow_allocations, _refill_waste_limit * HeapWordSize, 269 _allocation_fraction.average(), 270 _allocation_fraction.average() * tlab_used / K, 271 _number_of_refills, waste_percent, 272 _gc_waste * HeapWordSize, 273 _slow_refill_waste * HeapWordSize, 274 _fast_refill_waste * HeapWordSize); 275 } 276 277 void ThreadLocalAllocBuffer::verify() { 278 HeapWord* p = start(); 279 HeapWord* t = top(); 280 HeapWord* prev_p = NULL; 281 while (p < t) { 282 oop(p)->verify(); 283 prev_p = p; 284 p += oop(p)->size(); 285 } 286 guarantee(p == top(), "end of last object must match end of space"); 287 } 288 289 Thread* ThreadLocalAllocBuffer::myThread() { 290 return (Thread*)(((char *)this) + 291 in_bytes(start_offset()) - 292 in_bytes(Thread::tlab_start_offset())); 293 } 294 295 296 GlobalTLABStats::GlobalTLABStats() : 297 _allocating_threads_avg(TLABAllocationWeight) { 298 299 initialize(); 300 301 _allocating_threads_avg.sample(1); // One allocating thread at startup 302 303 if (UsePerfData) { 304 305 EXCEPTION_MARK; 306 ResourceMark rm; 307 308 char* cname = PerfDataManager::counter_name("tlab", "allocThreads"); 309 _perf_allocating_threads = 310 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 311 312 cname = PerfDataManager::counter_name("tlab", "fills"); 313 _perf_total_refills = 314 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 315 316 cname = PerfDataManager::counter_name("tlab", "maxFills"); 317 _perf_max_refills = 318 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 319 320 cname = PerfDataManager::counter_name("tlab", "alloc"); 321 _perf_allocation = 322 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 323 324 cname = PerfDataManager::counter_name("tlab", "gcWaste"); 325 _perf_gc_waste = 326 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 327 328 cname = PerfDataManager::counter_name("tlab", "maxGcWaste"); 329 _perf_max_gc_waste = 330 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 331 332 cname = PerfDataManager::counter_name("tlab", "slowWaste"); 333 _perf_slow_refill_waste = 334 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 335 336 cname = PerfDataManager::counter_name("tlab", "maxSlowWaste"); 337 _perf_max_slow_refill_waste = 338 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 339 340 cname = PerfDataManager::counter_name("tlab", "fastWaste"); 341 _perf_fast_refill_waste = 342 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 343 344 cname = PerfDataManager::counter_name("tlab", "maxFastWaste"); 345 _perf_max_fast_refill_waste = 346 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 347 348 cname = PerfDataManager::counter_name("tlab", "slowAlloc"); 349 _perf_slow_allocations = 350 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 351 352 cname = PerfDataManager::counter_name("tlab", "maxSlowAlloc"); 353 _perf_max_slow_allocations = 354 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 355 } 356 } 357 358 void GlobalTLABStats::initialize() { 359 // Clear counters summarizing info from all threads 360 _allocating_threads = 0; 361 _total_refills = 0; 362 _max_refills = 0; 363 _total_allocation = 0; 364 _total_gc_waste = 0; 365 _max_gc_waste = 0; 366 _total_slow_refill_waste = 0; 367 _max_slow_refill_waste = 0; 368 _total_fast_refill_waste = 0; 369 _max_fast_refill_waste = 0; 370 _total_slow_allocations = 0; 371 _max_slow_allocations = 0; 372 } 373 374 void GlobalTLABStats::publish() { 375 _allocating_threads_avg.sample(_allocating_threads); 376 if (UsePerfData) { 377 _perf_allocating_threads ->set_value(_allocating_threads); 378 _perf_total_refills ->set_value(_total_refills); 379 _perf_max_refills ->set_value(_max_refills); 380 _perf_allocation ->set_value(_total_allocation); 381 _perf_gc_waste ->set_value(_total_gc_waste); 382 _perf_max_gc_waste ->set_value(_max_gc_waste); 383 _perf_slow_refill_waste ->set_value(_total_slow_refill_waste); 384 _perf_max_slow_refill_waste->set_value(_max_slow_refill_waste); 385 _perf_fast_refill_waste ->set_value(_total_fast_refill_waste); 386 _perf_max_fast_refill_waste->set_value(_max_fast_refill_waste); 387 _perf_slow_allocations ->set_value(_total_slow_allocations); 388 _perf_max_slow_allocations ->set_value(_max_slow_allocations); 389 } 390 } 391 392 void GlobalTLABStats::print() { 393 size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste; 394 double waste_percent = _total_allocation == 0 ? 0.0 : 395 100.0 * waste / _total_allocation; 396 gclog_or_tty->print("TLAB totals: thrds: %d refills: %d max: %d" 397 " slow allocs: %d max %d waste: %4.1f%%" 398 " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" 399 " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" 400 " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B\n", 401 _allocating_threads, 402 _total_refills, _max_refills, 403 _total_slow_allocations, _max_slow_allocations, 404 waste_percent, 405 _total_gc_waste * HeapWordSize, 406 _max_gc_waste * HeapWordSize, 407 _total_slow_refill_waste * HeapWordSize, 408 _max_slow_refill_waste * HeapWordSize, 409 _total_fast_refill_waste * HeapWordSize, 410 _max_fast_refill_waste * HeapWordSize); 411 }