threadLocalAllocBuffer.hpp revision 11166:6525e4ba82a1 
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;
42  friend class JVMCIVMStructs;
43private:
44  HeapWord* _start;                              // address of TLAB
45  HeapWord* _top;                                // address after last allocation
46  HeapWord* _pf_top;                             // allocation prefetch watermark
47  HeapWord* _end;                                // allocation end (excluding alignment_reserve)
48  size_t    _desired_size;                       // desired size   (including alignment_reserve)
49  size_t    _refill_waste_limit;                 // hold onto tlab if free() is larger than this
50  size_t    _allocated_before_last_gc;           // total bytes allocated up until the last gc
51
52  static size_t   _max_size;                          // maximum size of any TLAB
53  static int      _reserve_for_allocation_prefetch;   // Reserve at the end of the TLAB
54  static unsigned _target_refills;                    // expected number of refills between GCs
55
56  unsigned  _number_of_refills;
57  unsigned  _fast_refill_waste;
58  unsigned  _slow_refill_waste;
59  unsigned  _gc_waste;
60  unsigned  _slow_allocations;
61
62  AdaptiveWeightedAverage _allocation_fraction;  // fraction of eden allocated in tlabs
63
64  void accumulate_statistics();
65  void initialize_statistics();
66
67  void set_start(HeapWord* start)                { _start = start; }
68  void set_end(HeapWord* end)                    { _end = end; }
69  void set_top(HeapWord* top)                    { _top = top; }
70  void set_pf_top(HeapWord* pf_top)              { _pf_top = pf_top; }
71  void set_desired_size(size_t desired_size)     { _desired_size = desired_size; }
72  void set_refill_waste_limit(size_t waste)      { _refill_waste_limit = waste;  }
73
74  size_t initial_refill_waste_limit()            { return desired_size() / TLABRefillWasteFraction; }
75
76  static int    target_refills()                 { return _target_refills; }
77  size_t initial_desired_size();
78
79  size_t remaining() const                       { return end() == NULL ? 0 : pointer_delta(hard_end(), top()); }
80
81  // Make parsable and release it.
82  void reset();
83
84  // Resize based on amount of allocation, etc.
85  void resize();
86
87  void invariants() const { assert(top() >= start() && top() <= end(), "invalid tlab"); }
88
89  void initialize(HeapWord* start, HeapWord* top, HeapWord* end);
90
91  void print_stats(const char* tag);
92
93  Thread* myThread();
94
95  // statistics
96
97  int number_of_refills() const { return _number_of_refills; }
98  int fast_refill_waste() const { return _fast_refill_waste; }
99  int slow_refill_waste() const { return _slow_refill_waste; }
100  int gc_waste() const          { return _gc_waste; }
101  int slow_allocations() const  { return _slow_allocations; }
102
103  static GlobalTLABStats* _global_stats;
104  static GlobalTLABStats* global_stats() { return _global_stats; }
105
106public:
107  ThreadLocalAllocBuffer() : _allocation_fraction(TLABAllocationWeight), _allocated_before_last_gc(0) {
108    // do nothing.  tlabs must be inited by initialize() calls
109  }
110
111  static const size_t min_size()                 { return align_object_size(MinTLABSize / HeapWordSize) + alignment_reserve(); }
112  static const size_t max_size()                 { assert(_max_size != 0, "max_size not set up"); return _max_size; }
113  static void set_max_size(size_t max_size)      { _max_size = max_size; }
114
115  HeapWord* start() const                        { return _start; }
116  HeapWord* end() const                          { return _end; }
117  HeapWord* hard_end() const                     { return _end + alignment_reserve(); }
118  HeapWord* top() const                          { return _top; }
119  HeapWord* pf_top() const                       { return _pf_top; }
120  size_t desired_size() const                    { return _desired_size; }
121  size_t used() const                            { return pointer_delta(top(), start()); }
122  size_t used_bytes() const                      { return pointer_delta(top(), start(), 1); }
123  size_t free() const                            { return pointer_delta(end(), top()); }
124  // Don't discard tlab if remaining space is larger than this.
125  size_t refill_waste_limit() const              { return _refill_waste_limit; }
126
127  // Allocate size HeapWords. The memory is NOT initialized to zero.
128  inline HeapWord* allocate(size_t size);
129
130  // Reserve space at the end of TLAB
131  static size_t end_reserve() {
132    int reserve_size = typeArrayOopDesc::header_size(T_INT);
133    return MAX2(reserve_size, _reserve_for_allocation_prefetch);
134  }
135  static size_t alignment_reserve()              { return align_object_size(end_reserve()); }
136  static size_t alignment_reserve_in_bytes()     { return alignment_reserve() * HeapWordSize; }
137
138  // Return tlab size or remaining space in eden such that the
139  // space is large enough to hold obj_size and necessary fill space.
140  // Otherwise return 0;
141  inline size_t compute_size(size_t obj_size);
142
143  // Record slow allocation
144  inline void record_slow_allocation(size_t obj_size);
145
146  // Initialization at startup
147  static void startup_initialization();
148
149  // Make an in-use tlab parsable, optionally retiring and/or zapping it.
150  void make_parsable(bool retire, bool zap = true);
151
152  // Retire in-use tlab before allocation of a new tlab
153  void clear_before_allocation();
154
155  // Accumulate statistics across all tlabs before gc
156  static void accumulate_statistics_before_gc();
157
158  // Resize tlabs for all threads
159  static void resize_all_tlabs();
160
161  void fill(HeapWord* start, HeapWord* top, size_t new_size);
162  void initialize();
163
164  static size_t refill_waste_limit_increment()   { return TLABWasteIncrement; }
165
166  // Code generation support
167  static ByteSize start_offset()                 { return byte_offset_of(ThreadLocalAllocBuffer, _start); }
168  static ByteSize end_offset()                   { return byte_offset_of(ThreadLocalAllocBuffer, _end  ); }
169  static ByteSize top_offset()                   { return byte_offset_of(ThreadLocalAllocBuffer, _top  ); }
170  static ByteSize pf_top_offset()                { return byte_offset_of(ThreadLocalAllocBuffer, _pf_top  ); }
171  static ByteSize size_offset()                  { return byte_offset_of(ThreadLocalAllocBuffer, _desired_size ); }
172  static ByteSize refill_waste_limit_offset()    { return byte_offset_of(ThreadLocalAllocBuffer, _refill_waste_limit ); }
173
174  static ByteSize number_of_refills_offset()     { return byte_offset_of(ThreadLocalAllocBuffer, _number_of_refills ); }
175  static ByteSize fast_refill_waste_offset()     { return byte_offset_of(ThreadLocalAllocBuffer, _fast_refill_waste ); }
176  static ByteSize slow_allocations_offset()      { return byte_offset_of(ThreadLocalAllocBuffer, _slow_allocations ); }
177
178  void verify();
179};
180
181class GlobalTLABStats: public CHeapObj<mtThread> {
182private:
183
184  // Accumulate perfdata in private variables because
185  // PerfData should be write-only for security reasons
186  // (see perfData.hpp)
187  unsigned _allocating_threads;
188  unsigned _total_refills;
189  unsigned _max_refills;
190  size_t   _total_allocation;
191  size_t   _total_gc_waste;
192  size_t   _max_gc_waste;
193  size_t   _total_slow_refill_waste;
194  size_t   _max_slow_refill_waste;
195  size_t   _total_fast_refill_waste;
196  size_t   _max_fast_refill_waste;
197  unsigned _total_slow_allocations;
198  unsigned _max_slow_allocations;
199
200  PerfVariable* _perf_allocating_threads;
201  PerfVariable* _perf_total_refills;
202  PerfVariable* _perf_max_refills;
203  PerfVariable* _perf_allocation;
204  PerfVariable* _perf_gc_waste;
205  PerfVariable* _perf_max_gc_waste;
206  PerfVariable* _perf_slow_refill_waste;
207  PerfVariable* _perf_max_slow_refill_waste;
208  PerfVariable* _perf_fast_refill_waste;
209  PerfVariable* _perf_max_fast_refill_waste;
210  PerfVariable* _perf_slow_allocations;
211  PerfVariable* _perf_max_slow_allocations;
212
213  AdaptiveWeightedAverage _allocating_threads_avg;
214
215public:
216  GlobalTLABStats();
217
218  // Initialize all counters
219  void initialize();
220
221  // Write all perf counters to the perf_counters
222  void publish();
223
224  void print();
225
226  // Accessors
227  unsigned allocating_threads_avg() {
228    return MAX2((unsigned)(_allocating_threads_avg.average() + 0.5), 1U);
229  }
230
231  size_t allocation() {
232    return _total_allocation;
233  }
234
235  // Update methods
236
237  void update_allocating_threads() {
238    _allocating_threads++;
239  }
240  void update_number_of_refills(unsigned value) {
241    _total_refills += value;
242    _max_refills    = MAX2(_max_refills, value);
243  }
244  void update_allocation(size_t value) {
245    _total_allocation += value;
246  }
247  void update_gc_waste(size_t value) {
248    _total_gc_waste += value;
249    _max_gc_waste    = MAX2(_max_gc_waste, value);
250  }
251  void update_fast_refill_waste(size_t value) {
252    _total_fast_refill_waste += value;
253    _max_fast_refill_waste    = MAX2(_max_fast_refill_waste, value);
254  }
255  void update_slow_refill_waste(size_t value) {
256    _total_slow_refill_waste += value;
257    _max_slow_refill_waste    = MAX2(_max_slow_refill_waste, value);
258  }
259  void update_slow_allocations(unsigned value) {
260    _total_slow_allocations += value;
261    _max_slow_allocations    = MAX2(_max_slow_allocations, value);
262  }
263};
264
265#endif // SHARE_VM_GC_SHARED_THREADLOCALALLOCBUFFER_HPP
266