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circular-queue.cc
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27 
28 #include "v8.h"
29 
30 #include "circular-queue-inl.h"
31 
32 namespace v8 {
33 namespace internal {
34 
35 
37  int desired_chunk_size_in_bytes,
38  int buffer_size_in_chunks)
39  : record_size_(record_size_in_bytes / sizeof(Cell)),
40  chunk_size_in_bytes_(desired_chunk_size_in_bytes / record_size_in_bytes *
41  record_size_in_bytes),
42  chunk_size_(chunk_size_in_bytes_ / sizeof(Cell)),
43  buffer_size_(chunk_size_ * buffer_size_in_chunks),
44  // The distance ensures that producer and consumer never step on
45  // each other's chunks and helps eviction of produced data from
46  // the CPU cache (having that chunk size is bigger than the cache.)
47  producer_consumer_distance_(2 * chunk_size_),
48  buffer_(NewArray<Cell>(buffer_size_ + 1)) {
49  ASSERT(buffer_size_in_chunks > 2);
50  // Clean up the whole buffer to avoid encountering a random kEnd
51  // while enqueuing.
52  for (int i = 0; i < buffer_size_; ++i) {
53  buffer_[i] = kClear;
54  }
55  buffer_[buffer_size_] = kEnd;
56 
57  // Layout producer and consumer position pointers each on their own
58  // cache lines to avoid cache lines thrashing due to simultaneous
59  // updates of positions by different processor cores.
60  const int positions_size =
62  RoundUp(static_cast<int>(sizeof(ProducerPosition)),
64  RoundUp(static_cast<int>(sizeof(ConsumerPosition)),
66  positions_ = NewArray<byte>(positions_size);
67 
68  producer_pos_ = reinterpret_cast<ProducerPosition*>(
69  RoundUp(positions_, kProcessorCacheLineSize));
70  producer_pos_->enqueue_pos = buffer_;
71 
72  consumer_pos_ = reinterpret_cast<ConsumerPosition*>(
73  reinterpret_cast<byte*>(producer_pos_) + kProcessorCacheLineSize);
74  ASSERT(reinterpret_cast<byte*>(consumer_pos_ + 1) <=
75  positions_ + positions_size);
76  consumer_pos_->dequeue_chunk_pos = buffer_;
77  consumer_pos_->dequeue_chunk_poll_pos = buffer_ + producer_consumer_distance_;
78  consumer_pos_->dequeue_pos = NULL;
79 }
80 
81 
83  DeleteArray(positions_);
84  DeleteArray(buffer_);
85 }
86 
87 
89  if (consumer_pos_->dequeue_pos != NULL) {
90  return consumer_pos_->dequeue_pos;
91  } else {
92  if (*consumer_pos_->dequeue_chunk_poll_pos != kClear) {
93  consumer_pos_->dequeue_pos = consumer_pos_->dequeue_chunk_pos;
94  consumer_pos_->dequeue_end_pos = consumer_pos_->dequeue_pos + chunk_size_;
95  return consumer_pos_->dequeue_pos;
96  } else {
97  return NULL;
98  }
99  }
100 }
101 
102 
104  consumer_pos_->dequeue_pos += record_size_;
105  if (consumer_pos_->dequeue_pos < consumer_pos_->dequeue_end_pos) return;
106  // Move to next chunk.
107  consumer_pos_->dequeue_pos = NULL;
108  *consumer_pos_->dequeue_chunk_pos = kClear;
109  consumer_pos_->dequeue_chunk_pos += chunk_size_;
110  WrapPositionIfNeeded(&consumer_pos_->dequeue_chunk_pos);
111  consumer_pos_->dequeue_chunk_poll_pos += chunk_size_;
112  WrapPositionIfNeeded(&consumer_pos_->dequeue_chunk_poll_pos);
113 }
114 
115 
117  // Eliminate producer / consumer distance.
118  consumer_pos_->dequeue_chunk_poll_pos = consumer_pos_->dequeue_chunk_pos;
119 }
120 
121 
122 } } // namespace v8::internal
SamplingCircularQueue(int record_size_in_bytes, int desired_chunk_size_in_bytes, int buffer_size_in_chunks)
const int kProcessorCacheLineSize
Definition: v8globals.h:97
#define ASSERT(condition)
Definition: checks.h:270
StringInputBuffer *const buffer_
uint8_t byte
Definition: globals.h:156
T * NewArray(size_t size)
Definition: allocation.h:83
T RoundUp(T x, intptr_t m)
Definition: utils.h:150
activate correct semantics for inheriting readonliness enable harmony semantics for typeof enable harmony enable harmony proxies enable all harmony harmony_scoping harmony_proxies harmony_scoping tracks arrays with only smi values automatically unbox arrays of doubles use crankshaft use hydrogen range analysis use hydrogen global value numbering use function inlining maximum number of AST nodes considered for a single inlining loop invariant code motion print statistics for hydrogen trace generated IR for specified phases trace register allocator trace range analysis trace representation types environment for every instruction put a break point before deoptimizing polymorphic inlining perform array bounds checks elimination use dead code elimination trace on stack replacement optimize closures cache optimized code for closures functions with arguments object loop weight for representation inference allow uint32 values on optimize frames if they are used only in safe operations track parallel recompilation enable all profiler experiments number of stack frames inspected by the profiler call recompile stub directly when self optimizing trigger profiler ticks based on counting instead of timing weight back edges by jump distance for interrupt triggering percentage of ICs that must have type info to allow optimization watch_ic_patching retry_self_opt interrupt_at_exit extra verbose compilation tracing generate extra emit comments in code disassembly enable use of SSE3 instructions if available enable use of CMOV instruction if available enable use of SAHF instruction if enable use of VFP3 instructions if available this implies enabling ARMv7 and VFP2 enable use of VFP2 instructions if available enable use of SDIV and UDIV instructions if enable loading bit constant by means of movw movt instruction enable unaligned accesses for enable use of MIPS FPU instructions if NULL
Definition: flags.cc:301
void DeleteArray(T *array)
Definition: allocation.h:91