1 /* 2 * Copyright (c) 1999, 2011, 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(); 117 118 if (retire) { 119 myThread()->incr_allocated_bytes(used_bytes()); 120 } 121 122 CollectedHeap::fill_with_object(top(), hard_end(), retire); 123 124 if (retire || ZeroTLAB) { // "Reset" the TLAB 125 set_start(NULL); 126 set_top(NULL); 127 set_pf_top(NULL); 128 set_end(NULL); 129 } 130 } 131 assert(!(retire || ZeroTLAB) || 132 (start() == NULL && end() == NULL && top() == NULL), 133 "TLAB must be reset"); 134 } 135 136 void ThreadLocalAllocBuffer::resize_all_tlabs() { 137 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) { 138 thread->tlab().resize(); 139 } 140 } 141 142 void ThreadLocalAllocBuffer::resize() { 143 144 if (ResizeTLAB) { 145 // Compute the next tlab size using expected allocation amount 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); 161 162 set_refill_waste_limit(initial_refill_waste_limit()); 163 } 164 } 165 166 void ThreadLocalAllocBuffer::initialize_statistics() { 167 _number_of_refills = 0; 168 _fast_refill_waste = 0; 169 _slow_refill_waste = 0; 170 _gc_waste = 0; 171 _slow_allocations = 0; 172 } 173 174 void ThreadLocalAllocBuffer::fill(HeapWord* start, 175 HeapWord* top, 176 size_t new_size) { 177 _number_of_refills++; 178 if (PrintTLAB && Verbose) { 179 print_stats("fill"); 180 } 181 assert(top <= start + new_size - alignment_reserve(), "size too small"); 182 initialize(start, top, start + new_size - alignment_reserve()); 183 184 // Reset amount of internal fragmentation 185 set_refill_waste_limit(initial_refill_waste_limit()); 186 } 187 188 void ThreadLocalAllocBuffer::initialize(HeapWord* start, 189 HeapWord* top, 190 HeapWord* end) { 191 set_start(start); 192 set_top(top); 193 set_pf_top(top); 194 set_end(end); 195 invariants(); 196 } 197 198 void ThreadLocalAllocBuffer::initialize() { 199 initialize(NULL, // start 200 NULL, // top 201 NULL); // end 202 203 set_desired_size(initial_desired_size()); 204 205 // Following check is needed because at startup the main (primordial) 206 // thread is initialized before the heap is. The initialization for 207 // this thread is redone in startup_initialization below. 208 if (Universe::heap() != NULL) { 209 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize; 210 double alloc_frac = desired_size() * target_refills() / (double) capacity; 211 _allocation_fraction.sample(alloc_frac); 212 } 213 214 set_refill_waste_limit(initial_refill_waste_limit()); 215 216 initialize_statistics(); 217 } 218 219 void ThreadLocalAllocBuffer::startup_initialization() { 220 221 // Assuming each thread's active tlab is, on average, 222 // 1/2 full at a GC 223 _target_refills = 100 / (2 * TLABWasteTargetPercent); 224 _target_refills = MAX2(_target_refills, (unsigned)1U); 225 226 _global_stats = new GlobalTLABStats(); 227 228 // During jvm startup, the main (primordial) thread is initialized 229 // before the heap is initialized. So reinitialize it now. 230 guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread"); 231 Thread::current()->tlab().initialize(); 232 233 if (PrintTLAB && Verbose) { 234 gclog_or_tty->print("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT "\n", 235 min_size(), Thread::current()->tlab().initial_desired_size(), max_size()); 236 } 237 } 238 239 size_t ThreadLocalAllocBuffer::initial_desired_size() { 240 size_t init_sz; 241 242 if (TLABSize > 0) { 243 init_sz = MIN2(TLABSize / HeapWordSize, max_size()); 244 } else if (global_stats() == NULL) { 245 // Startup issue - main thread initialized before heap initialized. 246 init_sz = min_size(); 247 } else { 248 // Initial size is a function of the average number of allocating threads. 249 unsigned nof_threads = global_stats()->allocating_threads_avg(); 250 251 init_sz = (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize) / 252 (nof_threads * target_refills()); 253 init_sz = align_object_size(init_sz); 254 init_sz = MIN2(MAX2(init_sz, min_size()), max_size()); 255 } 256 return init_sz; 257 } 258 259 const size_t ThreadLocalAllocBuffer::max_size() { 260 261 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE]. 262 // This restriction could be removed by enabling filling with multiple arrays. 263 // If we compute that the reasonable way as 264 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize) 265 // we'll overflow on the multiply, so we do the divide first. 266 // We actually lose a little by dividing first, 267 // but that just makes the TLAB somewhat smaller than the biggest array, 268 // which is fine, since we'll be able to fill that. 269 270 size_t unaligned_max_size = typeArrayOopDesc::header_size(T_INT) + 271 sizeof(jint) * 272 ((juint) max_jint / (size_t) HeapWordSize); 273 return align_size_down(unaligned_max_size, MinObjAlignment); 274 } 275 276 void ThreadLocalAllocBuffer::print_stats(const char* tag) { 277 Thread* thrd = myThread(); 278 size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste; 279 size_t alloc = _number_of_refills * _desired_size; 280 double waste_percent = alloc == 0 ? 0.0 : 281 100.0 * waste / alloc; 282 size_t tlab_used = Universe::heap()->tlab_capacity(thrd) - 283 Universe::heap()->unsafe_max_tlab_alloc(thrd); 284 gclog_or_tty->print("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]" 285 " desired_size: " SIZE_FORMAT "KB" 286 " slow allocs: %d refill waste: " SIZE_FORMAT "B" 287 " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB" 288 " slow: %dB fast: %dB\n", 289 tag, thrd, thrd->osthread()->thread_id(), 290 _desired_size / (K / HeapWordSize), 291 _slow_allocations, _refill_waste_limit * HeapWordSize, 292 _allocation_fraction.average(), 293 _allocation_fraction.average() * tlab_used / K, 294 _number_of_refills, waste_percent, 295 _gc_waste * HeapWordSize, 296 _slow_refill_waste * HeapWordSize, 297 _fast_refill_waste * HeapWordSize); 298 } 299 300 void ThreadLocalAllocBuffer::verify() { 301 HeapWord* p = start(); 302 HeapWord* t = top(); 303 HeapWord* prev_p = NULL; 304 while (p < t) { 305 oop(p)->verify(); 306 prev_p = p; 307 p += oop(p)->size(); 308 } 309 guarantee(p == top(), "end of last object must match end of space"); 310 } 311 312 Thread* ThreadLocalAllocBuffer::myThread() { 313 return (Thread*)(((char *)this) + 314 in_bytes(start_offset()) - 315 in_bytes(Thread::tlab_start_offset())); 316 } 317 318 319 GlobalTLABStats::GlobalTLABStats() : 320 _allocating_threads_avg(TLABAllocationWeight) { 321 322 initialize(); 323 324 _allocating_threads_avg.sample(1); // One allocating thread at startup 325 326 if (UsePerfData) { 327 328 EXCEPTION_MARK; 329 ResourceMark rm; 330 331 char* cname = PerfDataManager::counter_name("tlab", "allocThreads"); 332 _perf_allocating_threads = 333 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 334 335 cname = PerfDataManager::counter_name("tlab", "fills"); 336 _perf_total_refills = 337 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 338 339 cname = PerfDataManager::counter_name("tlab", "maxFills"); 340 _perf_max_refills = 341 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 342 343 cname = PerfDataManager::counter_name("tlab", "alloc"); 344 _perf_allocation = 345 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 346 347 cname = PerfDataManager::counter_name("tlab", "gcWaste"); 348 _perf_gc_waste = 349 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 350 351 cname = PerfDataManager::counter_name("tlab", "maxGcWaste"); 352 _perf_max_gc_waste = 353 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 354 355 cname = PerfDataManager::counter_name("tlab", "slowWaste"); 356 _perf_slow_refill_waste = 357 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 358 359 cname = PerfDataManager::counter_name("tlab", "maxSlowWaste"); 360 _perf_max_slow_refill_waste = 361 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 362 363 cname = PerfDataManager::counter_name("tlab", "fastWaste"); 364 _perf_fast_refill_waste = 365 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 366 367 cname = PerfDataManager::counter_name("tlab", "maxFastWaste"); 368 _perf_max_fast_refill_waste = 369 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); 370 371 cname = PerfDataManager::counter_name("tlab", "slowAlloc"); 372 _perf_slow_allocations = 373 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 374 375 cname = PerfDataManager::counter_name("tlab", "maxSlowAlloc"); 376 _perf_max_slow_allocations = 377 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); 378 } 379 } 380 381 void GlobalTLABStats::initialize() { 382 // Clear counters summarizing info from all threads 383 _allocating_threads = 0; 384 _total_refills = 0; 385 _max_refills = 0; 386 _total_allocation = 0; 387 _total_gc_waste = 0; 388 _max_gc_waste = 0; 389 _total_slow_refill_waste = 0; 390 _max_slow_refill_waste = 0; 391 _total_fast_refill_waste = 0; 392 _max_fast_refill_waste = 0; 393 _total_slow_allocations = 0; 394 _max_slow_allocations = 0; 395 } 396 397 void GlobalTLABStats::publish() { 398 _allocating_threads_avg.sample(_allocating_threads); 399 if (UsePerfData) { 400 _perf_allocating_threads ->set_value(_allocating_threads); 401 _perf_total_refills ->set_value(_total_refills); 402 _perf_max_refills ->set_value(_max_refills); 403 _perf_allocation ->set_value(_total_allocation); 404 _perf_gc_waste ->set_value(_total_gc_waste); 405 _perf_max_gc_waste ->set_value(_max_gc_waste); 406 _perf_slow_refill_waste ->set_value(_total_slow_refill_waste); 407 _perf_max_slow_refill_waste->set_value(_max_slow_refill_waste); 408 _perf_fast_refill_waste ->set_value(_total_fast_refill_waste); 409 _perf_max_fast_refill_waste->set_value(_max_fast_refill_waste); 410 _perf_slow_allocations ->set_value(_total_slow_allocations); 411 _perf_max_slow_allocations ->set_value(_max_slow_allocations); 412 } 413 } 414 415 void GlobalTLABStats::print() { 416 size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste; 417 double waste_percent = _total_allocation == 0 ? 0.0 : 418 100.0 * waste / _total_allocation; 419 gclog_or_tty->print("TLAB totals: thrds: %d refills: %d max: %d" 420 " slow allocs: %d max %d waste: %4.1f%%" 421 " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" 422 " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" 423 " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B\n", 424 _allocating_threads, 425 _total_refills, _max_refills, 426 _total_slow_allocations, _max_slow_allocations, 427 waste_percent, 428 _total_gc_waste * HeapWordSize, 429 _max_gc_waste * HeapWordSize, 430 _total_slow_refill_waste * HeapWordSize, 431 _max_slow_refill_waste * HeapWordSize, 432 _total_fast_refill_waste * HeapWordSize, 433 _max_fast_refill_waste * HeapWordSize); 434 }