threadLocalAllocBuffer.hpp revision 8413:92457dfb91bd 
1/*
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24
25#ifndef SHARE_VM_GC_SHARED_THREADLOCALALLOCBUFFER_HPP
26#define SHARE_VM_GC_SHARED_THREADLOCALALLOCBUFFER_HPP
27
28#include "gc/shared/gcUtil.hpp"
29#include "oops/typeArrayOop.hpp"
30#include "runtime/perfData.hpp"
31#include "runtime/vm_version.hpp"
32
33class GlobalTLABStats;
34
35// ThreadLocalAllocBuffer: a descriptor for thread-local storage used by
36// the threads for allocation.
37//            It is thread-private at any time, but maybe multiplexed over
38//            time across multiple threads. The park()/unpark() pair is
39//            used to make it available for such multiplexing.
40class ThreadLocalAllocBuffer: public CHeapObj<mtThread> {
41  friend class VMStructs;
42private:
43  HeapWord* _start;                              // address of TLAB
44  HeapWord* _top;                                // address after last allocation
45  HeapWord* _pf_top;                             // allocation prefetch watermark
46  HeapWord* _end;                                // allocation end (excluding alignment_reserve)
47  size_t    _desired_size;                       // desired size   (including alignment_reserve)
48  size_t    _refill_waste_limit;                 // hold onto tlab if free() is larger than this
49  size_t    _allocated_before_last_gc;           // total bytes allocated up until the last gc
50
51  static size_t   _max_size;                     // maximum size of any TLAB
52  static unsigned _target_refills;               // expected number of refills between GCs
53
54  unsigned  _number_of_refills;
55  unsigned  _fast_refill_waste;
56  unsigned  _slow_refill_waste;
57  unsigned  _gc_waste;
58  unsigned  _slow_allocations;
59
60  AdaptiveWeightedAverage _allocation_fraction;  // fraction of eden allocated in tlabs
61
62  void accumulate_statistics();
63  void initialize_statistics();
64
65  void set_start(HeapWord* start)                { _start = start; }
66  void set_end(HeapWord* end)                    { _end = end; }
67  void set_top(HeapWord* top)                    { _top = top; }
68  void set_pf_top(HeapWord* pf_top)              { _pf_top = pf_top; }
69  void set_desired_size(size_t desired_size)     { _desired_size = desired_size; }
70  void set_refill_waste_limit(size_t waste)      { _refill_waste_limit = waste;  }
71
72  size_t initial_refill_waste_limit()            { return desired_size() / TLABRefillWasteFraction; }
73
74  static int    target_refills()                 { return _target_refills; }
75  size_t initial_desired_size();
76
77  size_t remaining() const                       { return end() == NULL ? 0 : pointer_delta(hard_end(), top()); }
78
79  // Make parsable and release it.
80  void reset();
81
82  // Resize based on amount of allocation, etc.
83  void resize();
84
85  void invariants() const { assert(top() >= start() && top() <= end(), "invalid tlab"); }
86
87  void initialize(HeapWord* start, HeapWord* top, HeapWord* end);
88
89  void print_stats(const char* tag);
90
91  Thread* myThread();
92
93  // statistics
94
95  int number_of_refills() const { return _number_of_refills; }
96  int fast_refill_waste() const { return _fast_refill_waste; }
97  int slow_refill_waste() const { return _slow_refill_waste; }
98  int gc_waste() const          { return _gc_waste; }
99  int slow_allocations() const  { return _slow_allocations; }
100
101  static GlobalTLABStats* _global_stats;
102  static GlobalTLABStats* global_stats() { return _global_stats; }
103
104public:
105  ThreadLocalAllocBuffer() : _allocation_fraction(TLABAllocationWeight), _allocated_before_last_gc(0) {
106    // do nothing.  tlabs must be inited by initialize() calls
107  }
108
109  static const size_t min_size()                 { return align_object_size(MinTLABSize / HeapWordSize) + alignment_reserve(); }
110  static const size_t max_size()                 { assert(_max_size != 0, "max_size not set up"); return _max_size; }
111  static void set_max_size(size_t max_size)      { _max_size = max_size; }
112
113  HeapWord* start() const                        { return _start; }
114  HeapWord* end() const                          { return _end; }
115  HeapWord* hard_end() const                     { return _end + alignment_reserve(); }
116  HeapWord* top() const                          { return _top; }
117  HeapWord* pf_top() const                       { return _pf_top; }
118  size_t desired_size() const                    { return _desired_size; }
119  size_t used() const                            { return pointer_delta(top(), start()); }
120  size_t used_bytes() const                      { return pointer_delta(top(), start(), 1); }
121  size_t free() const                            { return pointer_delta(end(), top()); }
122  // Don't discard tlab if remaining space is larger than this.
123  size_t refill_waste_limit() const              { return _refill_waste_limit; }
124
125  // Allocate size HeapWords. The memory is NOT initialized to zero.
126  inline HeapWord* allocate(size_t size);
127
128  // Reserve space at the end of TLAB
129  static size_t end_reserve() {
130    int reserve_size = typeArrayOopDesc::header_size(T_INT);
131    return MAX2(reserve_size, VM_Version::reserve_for_allocation_prefetch());
132  }
133  static size_t alignment_reserve()              { return align_object_size(end_reserve()); }
134  static size_t alignment_reserve_in_bytes()     { return alignment_reserve() * HeapWordSize; }
135
136  // Return tlab size or remaining space in eden such that the
137  // space is large enough to hold obj_size and necessary fill space.
138  // Otherwise return 0;
139  inline size_t compute_size(size_t obj_size);
140
141  // Record slow allocation
142  inline void record_slow_allocation(size_t obj_size);
143
144  // Initialization at startup
145  static void startup_initialization();
146
147  // Make an in-use tlab parsable, optionally also retiring it.
148  void make_parsable(bool retire);
149
150  // Retire in-use tlab before allocation of a new tlab
151  void clear_before_allocation();
152
153  // Accumulate statistics across all tlabs before gc
154  static void accumulate_statistics_before_gc();
155
156  // Resize tlabs for all threads
157  static void resize_all_tlabs();
158
159  void fill(HeapWord* start, HeapWord* top, size_t new_size);
160  void initialize();
161
162  static size_t refill_waste_limit_increment()   { return TLABWasteIncrement; }
163
164  // Code generation support
165  static ByteSize start_offset()                 { return byte_offset_of(ThreadLocalAllocBuffer, _start); }
166  static ByteSize end_offset()                   { return byte_offset_of(ThreadLocalAllocBuffer, _end  ); }
167  static ByteSize top_offset()                   { return byte_offset_of(ThreadLocalAllocBuffer, _top  ); }
168  static ByteSize pf_top_offset()                { return byte_offset_of(ThreadLocalAllocBuffer, _pf_top  ); }
169  static ByteSize size_offset()                  { return byte_offset_of(ThreadLocalAllocBuffer, _desired_size ); }
170  static ByteSize refill_waste_limit_offset()    { return byte_offset_of(ThreadLocalAllocBuffer, _refill_waste_limit ); }
171
172  static ByteSize number_of_refills_offset()     { return byte_offset_of(ThreadLocalAllocBuffer, _number_of_refills ); }
173  static ByteSize fast_refill_waste_offset()     { return byte_offset_of(ThreadLocalAllocBuffer, _fast_refill_waste ); }
174  static ByteSize slow_allocations_offset()      { return byte_offset_of(ThreadLocalAllocBuffer, _slow_allocations ); }
175
176  void verify();
177};
178
179class GlobalTLABStats: public CHeapObj<mtThread> {
180private:
181
182  // Accumulate perfdata in private variables because
183  // PerfData should be write-only for security reasons
184  // (see perfData.hpp)
185  unsigned _allocating_threads;
186  unsigned _total_refills;
187  unsigned _max_refills;
188  size_t   _total_allocation;
189  size_t   _total_gc_waste;
190  size_t   _max_gc_waste;
191  size_t   _total_slow_refill_waste;
192  size_t   _max_slow_refill_waste;
193  size_t   _total_fast_refill_waste;
194  size_t   _max_fast_refill_waste;
195  unsigned _total_slow_allocations;
196  unsigned _max_slow_allocations;
197
198  PerfVariable* _perf_allocating_threads;
199  PerfVariable* _perf_total_refills;
200  PerfVariable* _perf_max_refills;
201  PerfVariable* _perf_allocation;
202  PerfVariable* _perf_gc_waste;
203  PerfVariable* _perf_max_gc_waste;
204  PerfVariable* _perf_slow_refill_waste;
205  PerfVariable* _perf_max_slow_refill_waste;
206  PerfVariable* _perf_fast_refill_waste;
207  PerfVariable* _perf_max_fast_refill_waste;
208  PerfVariable* _perf_slow_allocations;
209  PerfVariable* _perf_max_slow_allocations;
210
211  AdaptiveWeightedAverage _allocating_threads_avg;
212
213public:
214  GlobalTLABStats();
215
216  // Initialize all counters
217  void initialize();
218
219  // Write all perf counters to the perf_counters
220  void publish();
221
222  void print();
223
224  // Accessors
225  unsigned allocating_threads_avg() {
226    return MAX2((unsigned)(_allocating_threads_avg.average() + 0.5), 1U);
227  }
228
229  size_t allocation() {
230    return _total_allocation;
231  }
232
233  // Update methods
234
235  void update_allocating_threads() {
236    _allocating_threads++;
237  }
238  void update_number_of_refills(unsigned value) {
239    _total_refills += value;
240    _max_refills    = MAX2(_max_refills, value);
241  }
242  void update_allocation(size_t value) {
243    _total_allocation += value;
244  }
245  void update_gc_waste(size_t value) {
246    _total_gc_waste += value;
247    _max_gc_waste    = MAX2(_max_gc_waste, value);
248  }
249  void update_fast_refill_waste(size_t value) {
250    _total_fast_refill_waste += value;
251    _max_fast_refill_waste    = MAX2(_max_fast_refill_waste, value);
252  }
253  void update_slow_refill_waste(size_t value) {
254    _total_slow_refill_waste += value;
255    _max_slow_refill_waste    = MAX2(_max_slow_refill_waste, value);
256  }
257  void update_slow_allocations(unsigned value) {
258    _total_slow_allocations += value;
259    _max_slow_allocations    = MAX2(_max_slow_allocations, value);
260  }
261};
262
263#endif // SHARE_VM_GC_SHARED_THREADLOCALALLOCBUFFER_HPP
264