src/share/vm/memory/threadLocalAllocBuffer.cpp

Mon, 27 Jan 2014 13:14:53 +0100

author
brutisso
date
Mon, 27 Jan 2014 13:14:53 +0100
changeset 6376
cfd4aac53239
parent 4299
f34d701e952e
child 6680
78bbf4d43a14
permissions
-rw-r--r--

8030177: G1: Enable TLAB resizing
Reviewed-by: tschatzl, stefank, jmasa

     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  */
    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"
    34 // Thread-Local Edens support
    36 // static member initialization
    37 size_t           ThreadLocalAllocBuffer::_max_size       = 0;
    38 unsigned         ThreadLocalAllocBuffer::_target_refills = 0;
    39 GlobalTLABStats* ThreadLocalAllocBuffer::_global_stats   = NULL;
    41 void ThreadLocalAllocBuffer::clear_before_allocation() {
    42   _slow_refill_waste += (unsigned)remaining();
    43   make_parsable(true);   // also retire the TLAB
    44 }
    46 void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() {
    47   global_stats()->initialize();
    49   for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) {
    50     thread->tlab().accumulate_statistics();
    51     thread->tlab().initialize_statistics();
    52   }
    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 }
    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);
    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;
    73   if (PrintTLAB && (_number_of_refills > 0 || Verbose)) {
    74     print_stats("gc");
    75   }
    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;
    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);
    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 }
   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();
   115     if (retire) {
   116       myThread()->incr_allocated_bytes(used_bytes());
   117     }
   119     CollectedHeap::fill_with_object(top(), hard_end(), retire);
   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 }
   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 }
   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;
   148   new_size = MIN2(MAX2(new_size, min_size()), max_size());
   150   size_t aligned_new_size = align_object_size(new_size);
   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                         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 }
   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 }
   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());
   180   // Reset amount of internal fragmentation
   181   set_refill_waste_limit(initial_refill_waste_limit());
   182 }
   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 }
   194 void ThreadLocalAllocBuffer::initialize() {
   195   initialize(NULL,                    // start
   196              NULL,                    // top
   197              NULL);                   // end
   199   set_desired_size(initial_desired_size());
   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   }
   210   set_refill_waste_limit(initial_refill_waste_limit());
   212   initialize_statistics();
   213 }
   215 void ThreadLocalAllocBuffer::startup_initialization() {
   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);
   222   _global_stats = new GlobalTLABStats();
   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();
   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 }
   235 size_t ThreadLocalAllocBuffer::initial_desired_size() {
   236   size_t init_sz;
   238   if (TLABSize > 0) {
   239     init_sz = MIN2(TLABSize / HeapWordSize, max_size());
   240   } else if (global_stats() == NULL) {
   241     // Startup issue - main thread initialized before heap initialized.
   242     init_sz = min_size();
   243   } else {
   244     // Initial size is a function of the average number of allocating threads.
   245     unsigned nof_threads = global_stats()->allocating_threads_avg();
   247     init_sz  = (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize) /
   248                       (nof_threads * target_refills());
   249     init_sz = align_object_size(init_sz);
   250     init_sz = MIN2(MAX2(init_sz, min_size()), max_size());
   251   }
   252   return init_sz;
   253 }
   255 void ThreadLocalAllocBuffer::print_stats(const char* tag) {
   256   Thread* thrd = myThread();
   257   size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste;
   258   size_t alloc = _number_of_refills * _desired_size;
   259   double waste_percent = alloc == 0 ? 0.0 :
   260                       100.0 * waste / alloc;
   261   size_t tlab_used  = Universe::heap()->tlab_used(thrd);
   262   gclog_or_tty->print("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]"
   263                       " desired_size: " SIZE_FORMAT "KB"
   264                       " slow allocs: %d  refill waste: " SIZE_FORMAT "B"
   265                       " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB"
   266                       " slow: %dB fast: %dB\n",
   267                       tag, thrd, thrd->osthread()->thread_id(),
   268                       _desired_size / (K / HeapWordSize),
   269                       _slow_allocations, _refill_waste_limit * HeapWordSize,
   270                       _allocation_fraction.average(),
   271                       _allocation_fraction.average() * tlab_used / K,
   272                       _number_of_refills, waste_percent,
   273                       _gc_waste * HeapWordSize,
   274                       _slow_refill_waste * HeapWordSize,
   275                       _fast_refill_waste * HeapWordSize);
   276 }
   278 void ThreadLocalAllocBuffer::verify() {
   279   HeapWord* p = start();
   280   HeapWord* t = top();
   281   HeapWord* prev_p = NULL;
   282   while (p < t) {
   283     oop(p)->verify();
   284     prev_p = p;
   285     p += oop(p)->size();
   286   }
   287   guarantee(p == top(), "end of last object must match end of space");
   288 }
   290 Thread* ThreadLocalAllocBuffer::myThread() {
   291   return (Thread*)(((char *)this) +
   292                    in_bytes(start_offset()) -
   293                    in_bytes(Thread::tlab_start_offset()));
   294 }
   297 GlobalTLABStats::GlobalTLABStats() :
   298   _allocating_threads_avg(TLABAllocationWeight) {
   300   initialize();
   302   _allocating_threads_avg.sample(1); // One allocating thread at startup
   304   if (UsePerfData) {
   306     EXCEPTION_MARK;
   307     ResourceMark rm;
   309     char* cname = PerfDataManager::counter_name("tlab", "allocThreads");
   310     _perf_allocating_threads =
   311       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
   313     cname = PerfDataManager::counter_name("tlab", "fills");
   314     _perf_total_refills =
   315       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
   317     cname = PerfDataManager::counter_name("tlab", "maxFills");
   318     _perf_max_refills =
   319       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
   321     cname = PerfDataManager::counter_name("tlab", "alloc");
   322     _perf_allocation =
   323       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
   325     cname = PerfDataManager::counter_name("tlab", "gcWaste");
   326     _perf_gc_waste =
   327       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
   329     cname = PerfDataManager::counter_name("tlab", "maxGcWaste");
   330     _perf_max_gc_waste =
   331       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
   333     cname = PerfDataManager::counter_name("tlab", "slowWaste");
   334     _perf_slow_refill_waste =
   335       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
   337     cname = PerfDataManager::counter_name("tlab", "maxSlowWaste");
   338     _perf_max_slow_refill_waste =
   339       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
   341     cname = PerfDataManager::counter_name("tlab", "fastWaste");
   342     _perf_fast_refill_waste =
   343       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
   345     cname = PerfDataManager::counter_name("tlab", "maxFastWaste");
   346     _perf_max_fast_refill_waste =
   347       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
   349     cname = PerfDataManager::counter_name("tlab", "slowAlloc");
   350     _perf_slow_allocations =
   351       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
   353     cname = PerfDataManager::counter_name("tlab", "maxSlowAlloc");
   354     _perf_max_slow_allocations =
   355       PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
   356   }
   357 }
   359 void GlobalTLABStats::initialize() {
   360   // Clear counters summarizing info from all threads
   361   _allocating_threads      = 0;
   362   _total_refills           = 0;
   363   _max_refills             = 0;
   364   _total_allocation        = 0;
   365   _total_gc_waste          = 0;
   366   _max_gc_waste            = 0;
   367   _total_slow_refill_waste = 0;
   368   _max_slow_refill_waste   = 0;
   369   _total_fast_refill_waste = 0;
   370   _max_fast_refill_waste   = 0;
   371   _total_slow_allocations  = 0;
   372   _max_slow_allocations    = 0;
   373 }
   375 void GlobalTLABStats::publish() {
   376   _allocating_threads_avg.sample(_allocating_threads);
   377   if (UsePerfData) {
   378     _perf_allocating_threads   ->set_value(_allocating_threads);
   379     _perf_total_refills        ->set_value(_total_refills);
   380     _perf_max_refills          ->set_value(_max_refills);
   381     _perf_allocation           ->set_value(_total_allocation);
   382     _perf_gc_waste             ->set_value(_total_gc_waste);
   383     _perf_max_gc_waste         ->set_value(_max_gc_waste);
   384     _perf_slow_refill_waste    ->set_value(_total_slow_refill_waste);
   385     _perf_max_slow_refill_waste->set_value(_max_slow_refill_waste);
   386     _perf_fast_refill_waste    ->set_value(_total_fast_refill_waste);
   387     _perf_max_fast_refill_waste->set_value(_max_fast_refill_waste);
   388     _perf_slow_allocations     ->set_value(_total_slow_allocations);
   389     _perf_max_slow_allocations ->set_value(_max_slow_allocations);
   390   }
   391 }
   393 void GlobalTLABStats::print() {
   394   size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste;
   395   double waste_percent = _total_allocation == 0 ? 0.0 :
   396                          100.0 * waste / _total_allocation;
   397   gclog_or_tty->print("TLAB totals: thrds: %d  refills: %d max: %d"
   398                       " slow allocs: %d max %d waste: %4.1f%%"
   399                       " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"
   400                       " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"
   401                       " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B\n",
   402                       _allocating_threads,
   403                       _total_refills, _max_refills,
   404                       _total_slow_allocations, _max_slow_allocations,
   405                       waste_percent,
   406                       _total_gc_waste * HeapWordSize,
   407                       _max_gc_waste * HeapWordSize,
   408                       _total_slow_refill_waste * HeapWordSize,
   409                       _max_slow_refill_waste * HeapWordSize,
   410                       _total_fast_refill_waste * HeapWordSize,
   411                       _max_fast_refill_waste * HeapWordSize);
   412 }

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