1 // Copyright 2012 the V8 project authors. All rights reserved. 2 // Redistribution and use in source and binary forms, with or without 3 // modification, are permitted provided that the following conditions are 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 11 // with the distribution. 12 // * Neither the name of Google Inc. nor the names of its 13 // contributors may be used to endorse or promote products derived 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 #ifndef V8_RUNTIME_PROFILER_H_ 29 #define V8_RUNTIME_PROFILER_H_ 30 31 #include "allocation.h" 32 #include "atomicops.h" 33 34 namespace v8 { 35 namespace internal { 36 37 class Isolate; 38 class JSFunction; 39 class Object; 40 class Semaphore; 41 42 class RuntimeProfiler { 43 public: 44 explicit RuntimeProfiler(Isolate* isolate); 45 46 static void GlobalSetup(); 47 48 static inline bool IsEnabled() { 49 ASSERT(has_been_globally_set_up_); 50 return enabled_; 51 } 52 53 void OptimizeNow(); 54 55 void NotifyTick(); 56 57 void SetUp(); 58 void Reset(); 59 void TearDown(); 60 61 Object** SamplerWindowAddress(); 62 int SamplerWindowSize(); 63 64 void NotifyICChanged() { any_ic_changed_ = true; } 65 66 void NotifyCodeGenerated(int generated_code_size) { 67 if (FLAG_watch_ic_patching) { 68 code_generated_ = true; 69 total_code_generated_ += generated_code_size; 70 } 71 } 72 73 // Rate limiting support. 74 75 // VM thread interface. 76 // 77 // Called by isolates when their states change. 78 static inline void IsolateEnteredJS(Isolate* isolate); 79 static inline void IsolateExitedJS(Isolate* isolate); 80 81 // Profiler thread interface. 82 // 83 // IsSomeIsolateInJS(): 84 // The profiler thread can query whether some isolate is currently 85 // running JavaScript code. 86 // 87 // WaitForSomeIsolateToEnterJS(): 88 // When no isolates are running JavaScript code for some time the 89 // profiler thread suspends itself by calling the wait function. The 90 // wait function returns true after it waited or false immediately. 91 // While the function was waiting the profiler may have been 92 // disabled so it *must check* whether it is allowed to continue. 93 static bool IsSomeIsolateInJS(); 94 static bool WaitForSomeIsolateToEnterJS(); 95 96 // Stops the runtime profiler thread when profiling support is being 97 // turned off. 98 static void StopRuntimeProfilerThreadBeforeShutdown(Thread* thread); 99 100 void UpdateSamplesAfterScavenge(); 101 void RemoveDeadSamples(); 102 void UpdateSamplesAfterCompact(ObjectVisitor* visitor); 103 104 void AttemptOnStackReplacement(JSFunction* function); 105 106 private: 107 static const int kSamplerWindowSize = 16; 108 109 static void HandleWakeUp(Isolate* isolate); 110 111 void Optimize(JSFunction* function, const char* reason); 112 113 void ClearSampleBuffer(); 114 115 void ClearSampleBufferNewSpaceEntries(); 116 117 int LookupSample(JSFunction* function); 118 119 void AddSample(JSFunction* function, int weight); 120 121 Isolate* isolate_; 122 123 int sampler_threshold_; 124 int sampler_threshold_size_factor_; 125 int sampler_ticks_until_threshold_adjustment_; 126 127 Object* sampler_window_[kSamplerWindowSize]; 128 int sampler_window_position_; 129 int sampler_window_weight_[kSamplerWindowSize]; 130 131 bool any_ic_changed_; 132 bool code_generated_; 133 int total_code_generated_; 134 135 // Possible state values: 136 // -1 => the profiler thread is waiting on the semaphore 137 // 0 or positive => the number of isolates running JavaScript code. 138 static Atomic32 state_; 139 140 #ifdef DEBUG 141 static bool has_been_globally_set_up_; 142 #endif 143 static bool enabled_; 144 }; 145 146 147 // Rate limiter intended to be used in the profiler thread. 148 class RuntimeProfilerRateLimiter BASE_EMBEDDED { 149 public: 150 RuntimeProfilerRateLimiter() {} 151 152 // Suspends the current thread (which must be the profiler thread) 153 // when not executing JavaScript to minimize CPU usage. Returns 154 // whether the thread was suspended (and so must check whether 155 // profiling is still active.) 156 // 157 // Does nothing when runtime profiling is not enabled. 158 bool SuspendIfNecessary(); 159 160 private: 161 DISALLOW_COPY_AND_ASSIGN(RuntimeProfilerRateLimiter); 162 }; 163 164 165 // Implementation of RuntimeProfiler inline functions. 166 167 void RuntimeProfiler::IsolateEnteredJS(Isolate* isolate) { 168 Atomic32 new_state = NoBarrier_AtomicIncrement(&state_, 1); 169 if (new_state == 0) { 170 // Just incremented from -1 to 0. -1 can only be set by the 171 // profiler thread before it suspends itself and starts waiting on 172 // the semaphore. 173 HandleWakeUp(isolate); 174 } 175 ASSERT(new_state >= 0); 176 } 177 178 179 void RuntimeProfiler::IsolateExitedJS(Isolate* isolate) { 180 Atomic32 new_state = NoBarrier_AtomicIncrement(&state_, -1); 181 ASSERT(new_state >= 0); 182 USE(new_state); 183 } 184 185 } } // namespace v8::internal 186 187 #endif // V8_RUNTIME_PROFILER_H_ 188
