1 /* 2 * Copyright (c) 1999, 2015, 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/genCollectedHeap.hpp" 27 #include "gc/shared/threadLocalAllocBuffer.inline.hpp" 28 #include "memory/resourceArea.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 // Thread-Local Edens support 35 36 // static member initialization 37 size_t ThreadLocalAllocBuffer::_max_size = 0; 38 unsigned ThreadLocalAllocBuffer::_target_refills = 0; 39 GlobalTLABStats* ThreadLocalAllocBuffer::_global_stats = NULL; 40 41 void ThreadLocalAllocBuffer::clear_before_allocation() { 42 _slow_refill_waste += (unsigned)remaining(); 43 make_parsable(true); // also retire the TLAB 44 } 45 46 void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() { 47 global_stats()->initialize(); 48 49 for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) { 50 thread->tlab().accumulate_statistics(); 51 thread->tlab().initialize_statistics(); 52 } 53 54 // Publish new stats if some allocation occurred. 55 if (global_stats()->allocation() != 0) { 56 global_stats()->publish(); 57 if (PrintTLAB) { 58 global_stats()->print(); 59 } 60 } 61 } 62 63 void ThreadLocalAllocBuffer::accumulate_statistics() { 64 Thread* thread = myThread(); 65 size_t capacity = Universe::heap()->tlab_capacity(thread); 66 size_t used = Universe::heap()->tlab_used(thread); 67 68 _gc_waste += (unsigned)remaining(); 69 size_t total_allocated = thread->allocated_bytes(); 70 size_t allocated_since_last_gc = total_allocated - _allocated_before_last_gc; 71 _allocated_before_last_gc = total_allocated; 72 73 if (PrintTLAB && (_number_of_refills > 0 || Verbose)) { 74 print_stats("gc"); 75 } 76 77 if (_number_of_refills > 0) { 78 // Update allocation history if a reasonable amount of eden was allocated. 79 bool update_allocation_history = used > 0.5 * capacity; 80 81 if (update_allocation_history) { 82 // Average the fraction of eden allocated in a tlab by this 83 // thread for use in the next resize operation. 84 // _gc_waste is not subtracted because it's included in 85 // "used". 86 // The result can be larger than 1.0 due to direct to old allocations. 87 // These allocations should ideally not be counted but since it is not possible 88 // to filter them out here we just cap the fraction to be at most 1.0. 89 double alloc_frac = MIN2(1.0, (double) allocated_since_last_gc / used); 90 _allocation_fraction.sample(alloc_frac); 91 } 92 global_stats()->update_allocating_threads(); 93 global_stats()->update_number_of_refills(_number_of_refills); 94 global_stats()->update_allocation(_number_of_refills * desired_size()); 95 global_stats()->update_gc_waste(_gc_waste); 96 global_stats()->update_slow_refill_waste(_slow_refill_waste); 97 global_stats()->update_fast_refill_waste(_fast_refill_waste); 98 99 } else { 100 assert(_number_of_refills == 0 && _fast_refill_waste == 0 && 101 _slow_refill_waste == 0 && _gc_waste == 0, 102 "tlab stats == 0"); 103 } 104 global_stats()->update_slow_allocations(_slow_allocations); 105 } 106 107 // Fills the current tlab with a dummy filler array to create 108 // an illusion of a contiguous Eden and optionally retires the tlab. 109 // Waste accounting should be done in caller as appropriate; see, 110 // for example, clear_before_allocation(). 111 void ThreadLocalAllocBuffer::make_parsable(bool retire) { 112 if (end() != NULL) { 113 invariants(); 114 115 if (retire) { 116 myThread()->incr_allocated_bytes(used_bytes()); 117 } 118 119 CollectedHeap::fill_with_object(top(), hard_end(), retire); 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 (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) { 136 thread->tlab().resize(); 137 } 138 } 139 } 140 141 void ThreadLocalAllocBuffer::resize() { 142 // Compute the next tlab size using expected allocation amount 143 assert(ResizeTLAB, "Should not call this otherwise"); 144 size_t alloc = (size_t)(_allocation_fraction.average() * 145 (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize)); 146 size_t new_size = alloc / _target_refills; 147 148 new_size = MIN2(MAX2(new_size, min_size()), max_size()); 149 150 size_t aligned_new_size = align_object_size(new_size); 151 152 if (PrintTLAB && Verbose) { 153 gclog_or_tty->print("TLAB new size: thread: " INTPTR_FORMAT " [id: %2d]" 154 " refills %d alloc: %8.6f desired_size: " SIZE_FORMAT " -> " SIZE_FORMAT "\n", 155 p2i(myThread()), myThread()->osthread()->thread_id(), 156 _target_refills, _allocation_fraction.average(), desired_size(), aligned_new_size); 157 } 158 set_desired_size(aligned_new_size); 159 set_refill_waste_limit(initial_refill_waste_limit()); 160 } 161 162 void ThreadLocalAllocBuffer::initialize_statistics() { 163 _number_of_refills = 0; 164 _fast_refill_waste = 0; 165 _slow_refill_waste = 0; 166 _gc_waste = 0; 167 _slow_allocations = 0; 168 } 169 170 void ThreadLocalAllocBuffer::fill(HeapWord* start, 171 HeapWord* top, 172 size_t new_size) { 173 _number_of_refills++; 174 if (PrintTLAB && Verbose) { 175 print_stats("fill"); 176 } 177 assert(top <= start + new_size - alignment_reserve(), "size too small"); 178 initialize(start, top, start + new_size - alignment_reserve()); 179 180 // Reset amount of internal fragmentation 181 set_refill_waste_limit(initial_refill_waste_limit()); 182 } 183 184 void ThreadLocalAllocBuffer::initialize(HeapWord* start, 185 HeapWord* top, 186 HeapWord* end) { 187 set_start(start); 188 set_top(top); 189 set_pf_top(top); 190 set_end(end); 191 invariants(); 192 } 193 194 void ThreadLocalAllocBuffer::initialize() { 195 initialize(NULL, // start 196 NULL, // top 197 NULL); // end 198 199 set_desired_size(initial_desired_size()); 200 201 // Following check is needed because at startup the main (primordial) 202 // thread is initialized before the heap is. The initialization for 203 // this thread is redone in startup_initialization below. 204 if (Universe::heap() != NULL) { 205 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize; 206 double alloc_frac = desired_size() * target_refills() / (double) capacity; 207 _allocation_fraction.sample(alloc_frac); 208 } 209 210 set_refill_waste_limit(initial_refill_waste_limit()); 211 212 initialize_statistics(); 213 } 214 215 void ThreadLocalAllocBuffer::startup_initialization() { 216 217 // Assuming each thread's active tlab is, on average, 218 // 1/2 full at a GC 219 _target_refills = 100 / (2 * TLABWasteTargetPercent); 220 _target_refills = MAX2(_target_refills, (unsigned)1U); 221 222 _global_stats = new GlobalTLABStats(); 223 224 // During jvm startup, the main (primordial) thread is initialized 225 // before the heap is initialized. So reinitialize it now. 226 guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread"); 227 Thread::current()->tlab().initialize(); 228 229 if (PrintTLAB && Verbose) { 230 gclog_or_tty->print("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT "\n", 231 min_size(), Thread::current()->tlab().initial_desired_size(), max_size()); 232 } 233 } 234 235 size_t ThreadLocalAllocBuffer::initial_desired_size() { 236 size_t init_sz = 0; 237 238 if (TLABSize > 0) { 239 init_sz = TLABSize / HeapWordSize; 240 } else if (global_stats() != NULL) { 241 // Initial size is a function of the average number of allocating threads. 242 unsigned nof_threads = global_stats()->allocating_threads_avg(); 243 244 init_sz = (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize) / 245 (nof_threads * target_refills()); 246 init_sz = align_object_size(init_sz); 247 } 248 init_sz = MIN2(MAX2(init_sz, min_size()), max_size()); 249 return init_sz; 250 } 251 252 void ThreadLocalAllocBuffer::print_stats(const char* tag) { 253 Thread* thrd = myThread(); 254 size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste; 255 size_t alloc = _number_of_refills * _desired_size; 256 double waste_percent = alloc == 0 ? 0.0 : 257 100.0 * waste / alloc; 258 size_t tlab_used = Universe::heap()->tlab_used(thrd); 259 gclog_or_tty->print("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]" 260 " desired_size: " SIZE_FORMAT "KB" 261 " slow allocs: %d refill waste: " SIZE_FORMAT "B" 262 " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB" 263 " slow: %dB fast: %dB\n", 264 tag, p2i(thrd), thrd->osthread()->thread_id(), 265 _desired_size / (K / HeapWordSize), 266 _slow_allocations, _refill_waste_limit * HeapWordSize, 267 _allocation_fraction.average(), 268 _allocation_fraction.average() * tlab_used / K, 269 _number_of_refills, waste_percent, 270 _gc_waste * HeapWordSize, 271 _slow_refill_waste * HeapWordSize, 272 _fast_refill_waste * HeapWordSize); 273 } 274 275 void ThreadLocalAllocBuffer::verify() { 276 HeapWord* p = start(); 277 HeapWord* t = top(); 278 HeapWord* prev_p = NULL; 279 while (p < t) { 280 oop(p)->verify(); 281 prev_p = p; 282 p += oop(p)->size(); 283 } 284 guarantee(p == top(), "end of last object must match end of space"); 285 } 286 287 Thread* ThreadLocalAllocBuffer::myThread() { 288 return (Thread*)(((char *)this) + 289 in_bytes(start_offset()) - 290 in_bytes(Thread::tlab_start_offset())); 291 } 292 293 294 GlobalTLABStats::GlobalTLABStats() : 295 _allocating_threads_avg(TLABAllocationWeight) { 296 297 initialize(); 298 299 _allocating_threads_avg.sample(1); // One allocating thread at startup 300 301 if (UsePerfData) { 302 303 EXCEPTION_MARK; 304 ResourceMark rm; 305 306 char* cname = PerfDataManager::counter_name("tlab", "allocThreads"); 307 _perf_allocating_threads = 308 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 309 310 cname = PerfDataManager::counter_name("tlab", "fills"); 311 _perf_total_refills = 312 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 313 314 cname = PerfDataManager::counter_name("tlab", "maxFills"); 315 _perf_max_refills = 316 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 317 318 cname = PerfDataManager::counter_name("tlab", "alloc"); 319 _perf_allocation = 320 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 321 322 cname = PerfDataManager::counter_name("tlab", "gcWaste"); 323 _perf_gc_waste = 324 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 325 326 cname = PerfDataManager::counter_name("tlab", "maxGcWaste"); 327 _perf_max_gc_waste = 328 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 329 330 cname = PerfDataManager::counter_name("tlab", "slowWaste"); 331 _perf_slow_refill_waste = 332 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 333 334 cname = PerfDataManager::counter_name("tlab", "maxSlowWaste"); 335 _perf_max_slow_refill_waste = 336 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 337 338 cname = PerfDataManager::counter_name("tlab", "fastWaste"); 339 _perf_fast_refill_waste = 340 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 341 342 cname = PerfDataManager::counter_name("tlab", "maxFastWaste"); 343 _perf_max_fast_refill_waste = 344 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 345 346 cname = PerfDataManager::counter_name("tlab", "slowAlloc"); 347 _perf_slow_allocations = 348 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 349 350 cname = PerfDataManager::counter_name("tlab", "maxSlowAlloc"); 351 _perf_max_slow_allocations = 352 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 353 } 354 } 355 356 void GlobalTLABStats::initialize() { 357 // Clear counters summarizing info from all threads 358 _allocating_threads = 0; 359 _total_refills = 0; 360 _max_refills = 0; 361 _total_allocation = 0; 362 _total_gc_waste = 0; 363 _max_gc_waste = 0; 364 _total_slow_refill_waste = 0; 365 _max_slow_refill_waste = 0; 366 _total_fast_refill_waste = 0; 367 _max_fast_refill_waste = 0; 368 _total_slow_allocations = 0; 369 _max_slow_allocations = 0; 370 } 371 372 void GlobalTLABStats::publish() { 373 _allocating_threads_avg.sample(_allocating_threads); 374 if (UsePerfData) { 375 _perf_allocating_threads ->set_value(_allocating_threads); 376 _perf_total_refills ->set_value(_total_refills); 377 _perf_max_refills ->set_value(_max_refills); 378 _perf_allocation ->set_value(_total_allocation); 379 _perf_gc_waste ->set_value(_total_gc_waste); 380 _perf_max_gc_waste ->set_value(_max_gc_waste); 381 _perf_slow_refill_waste ->set_value(_total_slow_refill_waste); 382 _perf_max_slow_refill_waste->set_value(_max_slow_refill_waste); 383 _perf_fast_refill_waste ->set_value(_total_fast_refill_waste); 384 _perf_max_fast_refill_waste->set_value(_max_fast_refill_waste); 385 _perf_slow_allocations ->set_value(_total_slow_allocations); 386 _perf_max_slow_allocations ->set_value(_max_slow_allocations); 387 } 388 } 389 390 void GlobalTLABStats::print() { 391 size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste; 392 double waste_percent = _total_allocation == 0 ? 0.0 : 393 100.0 * waste / _total_allocation; 394 gclog_or_tty->print("TLAB totals: thrds: %d refills: %d max: %d" 395 " slow allocs: %d max %d waste: %4.1f%%" 396 " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" 397 " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" 398 " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B\n", 399 _allocating_threads, 400 _total_refills, _max_refills, 401 _total_slow_allocations, _max_slow_allocations, 402 waste_percent, 403 _total_gc_waste * HeapWordSize, 404 _max_gc_waste * HeapWordSize, 405 _total_slow_refill_waste * HeapWordSize, 406 _max_slow_refill_waste * HeapWordSize, 407 _total_fast_refill_waste * HeapWordSize, 408 _max_fast_refill_waste * HeapWordSize); 409 }