1 /* 2 * Copyright (c) 1999, 2010, 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 "utilities/copy.hpp" 32 #ifdef TARGET_OS_FAMILY_linux 33 # include "thread_linux.inline.hpp" 34 #endif 35 #ifdef TARGET_OS_FAMILY_solaris 36 # include "thread_solaris.inline.hpp" 37 #endif 38 #ifdef TARGET_OS_FAMILY_windows 39 # include "thread_windows.inline.hpp" 40 #endif 41 42 // Thread-Local Edens support 43 44 // static member initialization 45 unsigned ThreadLocalAllocBuffer::_target_refills = 0; 46 GlobalTLABStats* ThreadLocalAllocBuffer::_global_stats = NULL; 47 48 void ThreadLocalAllocBuffer::clear_before_allocation() { 49 _slow_refill_waste += (unsigned)remaining(); 50 make_parsable(true); // also retire the TLAB 51 } 52 53 void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() { 54 global_stats()->initialize(); 55 56 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) { 57 thread->tlab().accumulate_statistics(); 58 thread->tlab().initialize_statistics(); 59 } 60 61 // Publish new stats if some allocation occurred. 62 if (global_stats()->allocation() != 0) { 63 global_stats()->publish(); 64 if (PrintTLAB) { 65 global_stats()->print(); 66 } 67 } 68 } 69 70 void ThreadLocalAllocBuffer::accumulate_statistics() { 71 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize; 72 size_t unused = Universe::heap()->unsafe_max_tlab_alloc(myThread()) / HeapWordSize; 73 size_t used = capacity - unused; 74 75 // Update allocation history if a reasonable amount of eden was allocated. 76 bool update_allocation_history = used > 0.5 * capacity; 77 78 _gc_waste += (unsigned)remaining(); 79 80 if (PrintTLAB && (_number_of_refills > 0 || Verbose)) { 81 print_stats("gc"); 82 } 83 84 if (_number_of_refills > 0) { 85 86 if (update_allocation_history) { 87 // Average the fraction of eden allocated in a tlab by this 88 // thread for use in the next resize operation. 89 // _gc_waste is not subtracted because it's included in 90 // "used". 91 size_t allocation = _number_of_refills * desired_size(); 92 double alloc_frac = allocation / (double) used; 93 _allocation_fraction.sample(alloc_frac); 94 } 95 global_stats()->update_allocating_threads(); 96 global_stats()->update_number_of_refills(_number_of_refills); 97 global_stats()->update_allocation(_number_of_refills * desired_size()); 98 global_stats()->update_gc_waste(_gc_waste); 99 global_stats()->update_slow_refill_waste(_slow_refill_waste); 100 global_stats()->update_fast_refill_waste(_fast_refill_waste); 101 102 } else { 103 assert(_number_of_refills == 0 && _fast_refill_waste == 0 && 104 _slow_refill_waste == 0 && _gc_waste == 0, 105 "tlab stats == 0"); 106 } 107 global_stats()->update_slow_allocations(_slow_allocations); 108 } 109 110 // Fills the current tlab with a dummy filler array to create 111 // an illusion of a contiguous Eden and optionally retires the tlab. 112 // Waste accounting should be done in caller as appropriate; see, 113 // for example, clear_before_allocation(). 114 void ThreadLocalAllocBuffer::make_parsable(bool retire) { 115 if (end() != NULL) { 116 invariants(); 117 CollectedHeap::fill_with_object(top(), hard_end(), retire); 118 119 if (retire || ZeroTLAB) { // "Reset" the TLAB 120 set_start(NULL); 121 set_top(NULL); 122 set_pf_top(NULL); 123 set_end(NULL); 124 } 125 } 126 assert(!(retire || ZeroTLAB) || 127 (start() == NULL && end() == NULL && top() == NULL), 128 "TLAB must be reset"); 129 } 130 131 void ThreadLocalAllocBuffer::resize_all_tlabs() { 132 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) { 133 thread->tlab().resize(); 134 } 135 } 136 137 void ThreadLocalAllocBuffer::resize() { 138 139 if (ResizeTLAB) { 140 // Compute the next tlab size using expected allocation amount 141 size_t alloc = (size_t)(_allocation_fraction.average() * 142 (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize)); 143 size_t new_size = alloc / _target_refills; 144 145 new_size = MIN2(MAX2(new_size, min_size()), max_size()); 146 147 size_t aligned_new_size = align_object_size(new_size); 148 149 if (PrintTLAB && Verbose) { 150 gclog_or_tty->print("TLAB new size: thread: " INTPTR_FORMAT " [id: %2d]" 151 " refills %d alloc: %8.6f desired_size: " SIZE_FORMAT " -> " SIZE_FORMAT "\n", 152 myThread(), myThread()->osthread()->thread_id(), 153 _target_refills, _allocation_fraction.average(), desired_size(), aligned_new_size); 154 } 155 set_desired_size(aligned_new_size); 156 157 set_refill_waste_limit(initial_refill_waste_limit()); 158 } 159 } 160 161 void ThreadLocalAllocBuffer::initialize_statistics() { 162 _number_of_refills = 0; 163 _fast_refill_waste = 0; 164 _slow_refill_waste = 0; 165 _gc_waste = 0; 166 _slow_allocations = 0; 167 } 168 169 void ThreadLocalAllocBuffer::fill(HeapWord* start, 170 HeapWord* top, 171 size_t new_size) { 172 _number_of_refills++; 173 if (PrintTLAB && Verbose) { 174 print_stats("fill"); 175 } 176 assert(top <= start + new_size - alignment_reserve(), "size too small"); 177 initialize(start, top, start + new_size - alignment_reserve()); 178 179 // Reset amount of internal fragmentation 180 set_refill_waste_limit(initial_refill_waste_limit()); 181 } 182 183 void ThreadLocalAllocBuffer::initialize(HeapWord* start, 184 HeapWord* top, 185 HeapWord* end) { 186 set_start(start); 187 set_top(top); 188 set_pf_top(top); 189 set_end(end); 190 invariants(); 191 } 192 193 void ThreadLocalAllocBuffer::initialize() { 194 initialize(NULL, // start 195 NULL, // top 196 NULL); // end 197 198 set_desired_size(initial_desired_size()); 199 200 // Following check is needed because at startup the main (primordial) 201 // thread is initialized before the heap is. The initialization for 202 // this thread is redone in startup_initialization below. 203 if (Universe::heap() != NULL) { 204 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize; 205 double alloc_frac = desired_size() * target_refills() / (double) capacity; 206 _allocation_fraction.sample(alloc_frac); 207 } 208 209 set_refill_waste_limit(initial_refill_waste_limit()); 210 211 initialize_statistics(); 212 } 213 214 void ThreadLocalAllocBuffer::startup_initialization() { 215 216 // Assuming each thread's active tlab is, on average, 217 // 1/2 full at a GC 218 _target_refills = 100 / (2 * TLABWasteTargetPercent); 219 _target_refills = MAX2(_target_refills, (unsigned)1U); 220 221 _global_stats = new GlobalTLABStats(); 222 223 // During jvm startup, the main (primordial) thread is initialized 224 // before the heap is initialized. So reinitialize it now. 225 guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread"); 226 Thread::current()->tlab().initialize(); 227 228 if (PrintTLAB && Verbose) { 229 gclog_or_tty->print("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT "\n", 230 min_size(), Thread::current()->tlab().initial_desired_size(), max_size()); 231 } 232 } 233 234 size_t ThreadLocalAllocBuffer::initial_desired_size() { 235 size_t init_sz; 236 237 if (TLABSize > 0) { 238 init_sz = MIN2(TLABSize / HeapWordSize, max_size()); 239 } else if (global_stats() == NULL) { 240 // Startup issue - main thread initialized before heap initialized. 241 init_sz = min_size(); 242 } else { 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 init_sz = MIN2(MAX2(init_sz, min_size()), max_size()); 250 } 251 return init_sz; 252 } 253 254 const size_t ThreadLocalAllocBuffer::max_size() { 255 256 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE]. 257 // This restriction could be removed by enabling filling with multiple arrays. 258 // If we compute that the reasonable way as 259 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize) 260 // we'll overflow on the multiply, so we do the divide first. 261 // We actually lose a little by dividing first, 262 // but that just makes the TLAB somewhat smaller than the biggest array, 263 // which is fine, since we'll be able to fill that. 264 265 size_t unaligned_max_size = typeArrayOopDesc::header_size(T_INT) + 266 sizeof(jint) * 267 ((juint) max_jint / (size_t) HeapWordSize); 268 return align_size_down(unaligned_max_size, MinObjAlignment); 269 } 270 271 void ThreadLocalAllocBuffer::print_stats(const char* tag) { 272 Thread* thrd = myThread(); 273 size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste; 274 size_t alloc = _number_of_refills * _desired_size; 275 double waste_percent = alloc == 0 ? 0.0 : 276 100.0 * waste / alloc; 277 size_t tlab_used = Universe::heap()->tlab_capacity(thrd) - 278 Universe::heap()->unsafe_max_tlab_alloc(thrd); 279 gclog_or_tty->print("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]" 280 " desired_size: " SIZE_FORMAT "KB" 281 " slow allocs: %d refill waste: " SIZE_FORMAT "B" 282 " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB" 283 " slow: %dB fast: %dB\n", 284 tag, thrd, thrd->osthread()->thread_id(), 285 _desired_size / (K / HeapWordSize), 286 _slow_allocations, _refill_waste_limit * HeapWordSize, 287 _allocation_fraction.average(), 288 _allocation_fraction.average() * tlab_used / K, 289 _number_of_refills, waste_percent, 290 _gc_waste * HeapWordSize, 291 _slow_refill_waste * HeapWordSize, 292 _fast_refill_waste * HeapWordSize); 293 } 294 295 void ThreadLocalAllocBuffer::verify() { 296 HeapWord* p = start(); 297 HeapWord* t = top(); 298 HeapWord* prev_p = NULL; 299 while (p < t) { 300 oop(p)->verify(); 301 prev_p = p; 302 p += oop(p)->size(); 303 } 304 guarantee(p == top(), "end of last object must match end of space"); 305 } 306 307 Thread* ThreadLocalAllocBuffer::myThread() { 308 return (Thread*)(((char *)this) + 309 in_bytes(start_offset()) - 310 in_bytes(Thread::tlab_start_offset())); 311 } 312 313 314 GlobalTLABStats::GlobalTLABStats() : 315 _allocating_threads_avg(TLABAllocationWeight) { 316 317 initialize(); 318 319 _allocating_threads_avg.sample(1); // One allocating thread at startup 320 321 if (UsePerfData) { 322 323 EXCEPTION_MARK; 324 ResourceMark rm; 325 326 char* cname = PerfDataManager::counter_name("tlab", "allocThreads"); 327 _perf_allocating_threads = 328 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 329 330 cname = PerfDataManager::counter_name("tlab", "fills"); 331 _perf_total_refills = 332 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 333 334 cname = PerfDataManager::counter_name("tlab", "maxFills"); 335 _perf_max_refills = 336 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 337 338 cname = PerfDataManager::counter_name("tlab", "alloc"); 339 _perf_allocation = 340 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 341 342 cname = PerfDataManager::counter_name("tlab", "gcWaste"); 343 _perf_gc_waste = 344 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 345 346 cname = PerfDataManager::counter_name("tlab", "maxGcWaste"); 347 _perf_max_gc_waste = 348 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 349 350 cname = PerfDataManager::counter_name("tlab", "slowWaste"); 351 _perf_slow_refill_waste = 352 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 353 354 cname = PerfDataManager::counter_name("tlab", "maxSlowWaste"); 355 _perf_max_slow_refill_waste = 356 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 357 358 cname = PerfDataManager::counter_name("tlab", "fastWaste"); 359 _perf_fast_refill_waste = 360 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 361 362 cname = PerfDataManager::counter_name("tlab", "maxFastWaste"); 363 _perf_max_fast_refill_waste = 364 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 365 366 cname = PerfDataManager::counter_name("tlab", "slowAlloc"); 367 _perf_slow_allocations = 368 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 369 370 cname = PerfDataManager::counter_name("tlab", "maxSlowAlloc"); 371 _perf_max_slow_allocations = 372 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 373 } 374 } 375 376 void GlobalTLABStats::initialize() { 377 // Clear counters summarizing info from all threads 378 _allocating_threads = 0; 379 _total_refills = 0; 380 _max_refills = 0; 381 _total_allocation = 0; 382 _total_gc_waste = 0; 383 _max_gc_waste = 0; 384 _total_slow_refill_waste = 0; 385 _max_slow_refill_waste = 0; 386 _total_fast_refill_waste = 0; 387 _max_fast_refill_waste = 0; 388 _total_slow_allocations = 0; 389 _max_slow_allocations = 0; 390 } 391 392 void GlobalTLABStats::publish() { 393 _allocating_threads_avg.sample(_allocating_threads); 394 if (UsePerfData) { 395 _perf_allocating_threads ->set_value(_allocating_threads); 396 _perf_total_refills ->set_value(_total_refills); 397 _perf_max_refills ->set_value(_max_refills); 398 _perf_allocation ->set_value(_total_allocation); 399 _perf_gc_waste ->set_value(_total_gc_waste); 400 _perf_max_gc_waste ->set_value(_max_gc_waste); 401 _perf_slow_refill_waste ->set_value(_total_slow_refill_waste); 402 _perf_max_slow_refill_waste->set_value(_max_slow_refill_waste); 403 _perf_fast_refill_waste ->set_value(_total_fast_refill_waste); 404 _perf_max_fast_refill_waste->set_value(_max_fast_refill_waste); 405 _perf_slow_allocations ->set_value(_total_slow_allocations); 406 _perf_max_slow_allocations ->set_value(_max_slow_allocations); 407 } 408 } 409 410 void GlobalTLABStats::print() { 411 size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste; 412 double waste_percent = _total_allocation == 0 ? 0.0 : 413 100.0 * waste / _total_allocation; 414 gclog_or_tty->print("TLAB totals: thrds: %d refills: %d max: %d" 415 " slow allocs: %d max %d waste: %4.1f%%" 416 " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" 417 " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" 418 " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B\n", 419 _allocating_threads, 420 _total_refills, _max_refills, 421 _total_slow_allocations, _max_slow_allocations, 422 waste_percent, 423 _total_gc_waste * HeapWordSize, 424 _max_gc_waste * HeapWordSize, 425 _total_slow_refill_waste * HeapWordSize, 426 _max_slow_refill_waste * HeapWordSize, 427 _total_fast_refill_waste * HeapWordSize, 428 _max_fast_refill_waste * HeapWordSize); 429 }