| // Copyright 2012 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #include "v8.h" |
| |
| #include "runtime-profiler.h" |
| |
| #include "assembler.h" |
| #include "code-stubs.h" |
| #include "compilation-cache.h" |
| #include "deoptimizer.h" |
| #include "execution.h" |
| #include "global-handles.h" |
| #include "isolate-inl.h" |
| #include "mark-compact.h" |
| #include "platform.h" |
| #include "scopeinfo.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| |
| // Optimization sampler constants. |
| static const int kSamplerFrameCount = 2; |
| |
| // Constants for statistical profiler. |
| static const int kSamplerFrameWeight[kSamplerFrameCount] = { 2, 1 }; |
| |
| static const int kSamplerTicksBetweenThresholdAdjustment = 32; |
| |
| static const int kSamplerThresholdInit = 3; |
| static const int kSamplerThresholdMin = 1; |
| static const int kSamplerThresholdDelta = 1; |
| |
| static const int kSamplerThresholdSizeFactorInit = 3; |
| |
| static const int kSizeLimit = 1500; |
| |
| // Constants for counter based profiler. |
| |
| // Number of times a function has to be seen on the stack before it is |
| // optimized. |
| static const int kProfilerTicksBeforeOptimization = 2; |
| // If the function optimization was disabled due to high deoptimization count, |
| // but the function is hot and has been seen on the stack this number of times, |
| // then we try to reenable optimization for this function. |
| static const int kProfilerTicksBeforeReenablingOptimization = 250; |
| // If a function does not have enough type info (according to |
| // FLAG_type_info_threshold), but has seen a huge number of ticks, |
| // optimize it as it is. |
| static const int kTicksWhenNotEnoughTypeInfo = 100; |
| // We only have one byte to store the number of ticks. |
| STATIC_ASSERT(kProfilerTicksBeforeOptimization < 256); |
| STATIC_ASSERT(kProfilerTicksBeforeReenablingOptimization < 256); |
| STATIC_ASSERT(kTicksWhenNotEnoughTypeInfo < 256); |
| |
| |
| // Maximum size in bytes of generated code for a function to be optimized |
| // the very first time it is seen on the stack. |
| static const int kMaxSizeEarlyOpt = 500; |
| |
| |
| Atomic32 RuntimeProfiler::state_ = 0; |
| |
| // TODO(isolates): Clean up the semaphore when it is no longer required. |
| static LazySemaphore<0>::type semaphore = LAZY_SEMAPHORE_INITIALIZER; |
| |
| #ifdef DEBUG |
| bool RuntimeProfiler::has_been_globally_set_up_ = false; |
| #endif |
| bool RuntimeProfiler::enabled_ = false; |
| |
| |
| RuntimeProfiler::RuntimeProfiler(Isolate* isolate) |
| : isolate_(isolate), |
| sampler_threshold_(kSamplerThresholdInit), |
| sampler_threshold_size_factor_(kSamplerThresholdSizeFactorInit), |
| sampler_ticks_until_threshold_adjustment_( |
| kSamplerTicksBetweenThresholdAdjustment), |
| sampler_window_position_(0), |
| any_ic_changed_(false), |
| code_generated_(false) { |
| ClearSampleBuffer(); |
| } |
| |
| |
| void RuntimeProfiler::GlobalSetUp() { |
| ASSERT(!has_been_globally_set_up_); |
| enabled_ = V8::UseCrankshaft() && FLAG_opt; |
| #ifdef DEBUG |
| has_been_globally_set_up_ = true; |
| #endif |
| } |
| |
| |
| static void GetICCounts(JSFunction* function, |
| int* ic_with_type_info_count, |
| int* ic_total_count, |
| int* percentage) { |
| *ic_total_count = 0; |
| *ic_with_type_info_count = 0; |
| Object* raw_info = |
| function->shared()->code()->type_feedback_info(); |
| if (raw_info->IsTypeFeedbackInfo()) { |
| TypeFeedbackInfo* info = TypeFeedbackInfo::cast(raw_info); |
| *ic_with_type_info_count = info->ic_with_type_info_count(); |
| *ic_total_count = info->ic_total_count(); |
| } |
| *percentage = *ic_total_count > 0 |
| ? 100 * *ic_with_type_info_count / *ic_total_count |
| : 100; |
| } |
| |
| |
| void RuntimeProfiler::Optimize(JSFunction* function, const char* reason) { |
| ASSERT(function->IsOptimizable()); |
| if (FLAG_trace_opt) { |
| PrintF("[marking "); |
| function->PrintName(); |
| PrintF(" 0x%" V8PRIxPTR, reinterpret_cast<intptr_t>(function->address())); |
| PrintF(" for recompilation, reason: %s", reason); |
| if (FLAG_type_info_threshold > 0) { |
| int typeinfo, total, percentage; |
| GetICCounts(function, &typeinfo, &total, &percentage); |
| PrintF(", ICs with typeinfo: %d/%d (%d%%)", typeinfo, total, percentage); |
| } |
| PrintF("]\n"); |
| } |
| |
| if (FLAG_parallel_recompilation) { |
| function->MarkForParallelRecompilation(); |
| } else { |
| // The next call to the function will trigger optimization. |
| function->MarkForLazyRecompilation(); |
| } |
| } |
| |
| |
| void RuntimeProfiler::AttemptOnStackReplacement(JSFunction* function) { |
| // See AlwaysFullCompiler (in compiler.cc) comment on why we need |
| // Debug::has_break_points(). |
| ASSERT(function->IsMarkedForLazyRecompilation() || |
| function->IsMarkedForParallelRecompilation()); |
| if (!FLAG_use_osr || |
| isolate_->DebuggerHasBreakPoints() || |
| function->IsBuiltin()) { |
| return; |
| } |
| |
| SharedFunctionInfo* shared = function->shared(); |
| // If the code is not optimizable, don't try OSR. |
| if (!shared->code()->optimizable()) return; |
| |
| // We are not prepared to do OSR for a function that already has an |
| // allocated arguments object. The optimized code would bypass it for |
| // arguments accesses, which is unsound. Don't try OSR. |
| if (shared->uses_arguments()) return; |
| |
| // We're using on-stack replacement: patch the unoptimized code so that |
| // any back edge in any unoptimized frame will trigger on-stack |
| // replacement for that frame. |
| if (FLAG_trace_osr) { |
| PrintF("[patching stack checks in "); |
| function->PrintName(); |
| PrintF(" for on-stack replacement]\n"); |
| } |
| |
| // Get the stack check stub code object to match against. We aren't |
| // prepared to generate it, but we don't expect to have to. |
| bool found_code = false; |
| Code* stack_check_code = NULL; |
| if (FLAG_count_based_interrupts) { |
| InterruptStub interrupt_stub; |
| found_code = interrupt_stub.FindCodeInCache(&stack_check_code); |
| } else // NOLINT |
| { // NOLINT |
| StackCheckStub check_stub; |
| found_code = check_stub.FindCodeInCache(&stack_check_code); |
| } |
| if (found_code) { |
| Code* replacement_code = |
| isolate_->builtins()->builtin(Builtins::kOnStackReplacement); |
| Code* unoptimized_code = shared->code(); |
| Deoptimizer::PatchStackCheckCode(unoptimized_code, |
| stack_check_code, |
| replacement_code); |
| } |
| } |
| |
| |
| void RuntimeProfiler::ClearSampleBuffer() { |
| memset(sampler_window_, 0, sizeof(sampler_window_)); |
| memset(sampler_window_weight_, 0, sizeof(sampler_window_weight_)); |
| } |
| |
| |
| int RuntimeProfiler::LookupSample(JSFunction* function) { |
| int weight = 0; |
| for (int i = 0; i < kSamplerWindowSize; i++) { |
| Object* sample = sampler_window_[i]; |
| if (sample != NULL) { |
| bool fits = FLAG_lookup_sample_by_shared |
| ? (function->shared() == JSFunction::cast(sample)->shared()) |
| : (function == JSFunction::cast(sample)); |
| if (fits) { |
| weight += sampler_window_weight_[i]; |
| } |
| } |
| } |
| return weight; |
| } |
| |
| |
| void RuntimeProfiler::AddSample(JSFunction* function, int weight) { |
| ASSERT(IsPowerOf2(kSamplerWindowSize)); |
| sampler_window_[sampler_window_position_] = function; |
| sampler_window_weight_[sampler_window_position_] = weight; |
| sampler_window_position_ = (sampler_window_position_ + 1) & |
| (kSamplerWindowSize - 1); |
| } |
| |
| |
| void RuntimeProfiler::OptimizeNow() { |
| HandleScope scope(isolate_); |
| |
| // Run through the JavaScript frames and collect them. If we already |
| // have a sample of the function, we mark it for optimizations |
| // (eagerly or lazily). |
| JSFunction* samples[kSamplerFrameCount]; |
| int sample_count = 0; |
| int frame_count = 0; |
| int frame_count_limit = FLAG_watch_ic_patching ? FLAG_frame_count |
| : kSamplerFrameCount; |
| for (JavaScriptFrameIterator it(isolate_); |
| frame_count++ < frame_count_limit && !it.done(); |
| it.Advance()) { |
| JavaScriptFrame* frame = it.frame(); |
| JSFunction* function = JSFunction::cast(frame->function()); |
| |
| if (!FLAG_watch_ic_patching) { |
| // Adjust threshold each time we have processed |
| // a certain number of ticks. |
| if (sampler_ticks_until_threshold_adjustment_ > 0) { |
| sampler_ticks_until_threshold_adjustment_--; |
| if (sampler_ticks_until_threshold_adjustment_ <= 0) { |
| // If the threshold is not already at the minimum |
| // modify and reset the ticks until next adjustment. |
| if (sampler_threshold_ > kSamplerThresholdMin) { |
| sampler_threshold_ -= kSamplerThresholdDelta; |
| sampler_ticks_until_threshold_adjustment_ = |
| kSamplerTicksBetweenThresholdAdjustment; |
| } |
| } |
| } |
| } |
| |
| SharedFunctionInfo* shared = function->shared(); |
| Code* shared_code = shared->code(); |
| |
| if (shared_code->kind() != Code::FUNCTION) continue; |
| |
| if (function->IsMarkedForLazyRecompilation() || |
| function->IsMarkedForParallelRecompilation()) { |
| int nesting = shared_code->allow_osr_at_loop_nesting_level(); |
| if (nesting == 0) AttemptOnStackReplacement(function); |
| int new_nesting = Min(nesting + 1, Code::kMaxLoopNestingMarker); |
| shared_code->set_allow_osr_at_loop_nesting_level(new_nesting); |
| } |
| |
| // Only record top-level code on top of the execution stack and |
| // avoid optimizing excessively large scripts since top-level code |
| // will be executed only once. |
| const int kMaxToplevelSourceSize = 10 * 1024; |
| if (shared->is_toplevel() && |
| (frame_count > 1 || shared->SourceSize() > kMaxToplevelSourceSize)) { |
| continue; |
| } |
| |
| // Do not record non-optimizable functions. |
| if (shared->optimization_disabled()) { |
| if (shared->deopt_count() >= Compiler::kDefaultMaxOptCount) { |
| // If optimization was disabled due to many deoptimizations, |
| // then check if the function is hot and try to reenable optimization. |
| int ticks = shared_code->profiler_ticks(); |
| if (ticks >= kProfilerTicksBeforeReenablingOptimization) { |
| shared_code->set_profiler_ticks(0); |
| shared->TryReenableOptimization(); |
| } else { |
| shared_code->set_profiler_ticks(ticks + 1); |
| } |
| } |
| continue; |
| } |
| if (!function->IsOptimizable()) continue; |
| |
| |
| |
| if (FLAG_watch_ic_patching) { |
| int ticks = shared_code->profiler_ticks(); |
| |
| if (ticks >= kProfilerTicksBeforeOptimization) { |
| int typeinfo, total, percentage; |
| GetICCounts(function, &typeinfo, &total, &percentage); |
| if (percentage >= FLAG_type_info_threshold) { |
| // If this particular function hasn't had any ICs patched for enough |
| // ticks, optimize it now. |
| Optimize(function, "hot and stable"); |
| } else if (ticks >= kTicksWhenNotEnoughTypeInfo) { |
| Optimize(function, "not much type info but very hot"); |
| } else { |
| shared_code->set_profiler_ticks(ticks + 1); |
| if (FLAG_trace_opt_verbose) { |
| PrintF("[not yet optimizing "); |
| function->PrintName(); |
| PrintF(", not enough type info: %d/%d (%d%%)]\n", |
| typeinfo, total, percentage); |
| } |
| } |
| } else if (!any_ic_changed_ && |
| shared_code->instruction_size() < kMaxSizeEarlyOpt) { |
| // If no IC was patched since the last tick and this function is very |
| // small, optimistically optimize it now. |
| Optimize(function, "small function"); |
| } else { |
| shared_code->set_profiler_ticks(ticks + 1); |
| } |
| } else { // !FLAG_watch_ic_patching |
| samples[sample_count++] = function; |
| |
| int function_size = function->shared()->SourceSize(); |
| int threshold_size_factor = (function_size > kSizeLimit) |
| ? sampler_threshold_size_factor_ |
| : 1; |
| |
| int threshold = sampler_threshold_ * threshold_size_factor; |
| |
| if (LookupSample(function) >= threshold) { |
| Optimize(function, "sampler window lookup"); |
| } |
| } |
| } |
| if (FLAG_watch_ic_patching) { |
| any_ic_changed_ = false; |
| } else { // !FLAG_watch_ic_patching |
| // Add the collected functions as samples. It's important not to do |
| // this as part of collecting them because this will interfere with |
| // the sample lookup in case of recursive functions. |
| for (int i = 0; i < sample_count; i++) { |
| AddSample(samples[i], kSamplerFrameWeight[i]); |
| } |
| } |
| } |
| |
| |
| void RuntimeProfiler::NotifyTick() { |
| if (FLAG_count_based_interrupts) return; |
| isolate_->stack_guard()->RequestRuntimeProfilerTick(); |
| } |
| |
| |
| void RuntimeProfiler::SetUp() { |
| ASSERT(has_been_globally_set_up_); |
| if (!FLAG_watch_ic_patching) { |
| ClearSampleBuffer(); |
| } |
| // If the ticker hasn't already started, make sure to do so to get |
| // the ticks for the runtime profiler. |
| if (IsEnabled()) isolate_->logger()->EnsureTickerStarted(); |
| } |
| |
| |
| void RuntimeProfiler::Reset() { |
| if (!FLAG_watch_ic_patching) { |
| sampler_threshold_ = kSamplerThresholdInit; |
| sampler_threshold_size_factor_ = kSamplerThresholdSizeFactorInit; |
| sampler_ticks_until_threshold_adjustment_ = |
| kSamplerTicksBetweenThresholdAdjustment; |
| } |
| } |
| |
| |
| void RuntimeProfiler::TearDown() { |
| // Nothing to do. |
| } |
| |
| |
| int RuntimeProfiler::SamplerWindowSize() { |
| return kSamplerWindowSize; |
| } |
| |
| |
| // Update the pointers in the sampler window after a GC. |
| void RuntimeProfiler::UpdateSamplesAfterScavenge() { |
| for (int i = 0; i < kSamplerWindowSize; i++) { |
| Object* function = sampler_window_[i]; |
| if (function != NULL && isolate_->heap()->InNewSpace(function)) { |
| MapWord map_word = HeapObject::cast(function)->map_word(); |
| if (map_word.IsForwardingAddress()) { |
| sampler_window_[i] = map_word.ToForwardingAddress(); |
| } else { |
| sampler_window_[i] = NULL; |
| } |
| } |
| } |
| } |
| |
| |
| void RuntimeProfiler::HandleWakeUp(Isolate* isolate) { |
| // The profiler thread must still be waiting. |
| ASSERT(NoBarrier_Load(&state_) >= 0); |
| // In IsolateEnteredJS we have already incremented the counter and |
| // undid the decrement done by the profiler thread. Increment again |
| // to get the right count of active isolates. |
| NoBarrier_AtomicIncrement(&state_, 1); |
| semaphore.Pointer()->Signal(); |
| } |
| |
| |
| bool RuntimeProfiler::IsSomeIsolateInJS() { |
| return NoBarrier_Load(&state_) > 0; |
| } |
| |
| |
| bool RuntimeProfiler::WaitForSomeIsolateToEnterJS() { |
| Atomic32 old_state = NoBarrier_CompareAndSwap(&state_, 0, -1); |
| ASSERT(old_state >= -1); |
| if (old_state != 0) return false; |
| semaphore.Pointer()->Wait(); |
| return true; |
| } |
| |
| |
| void RuntimeProfiler::StopRuntimeProfilerThreadBeforeShutdown(Thread* thread) { |
| // Do a fake increment. If the profiler is waiting on the semaphore, |
| // the returned state is 0, which can be left as an initial state in |
| // case profiling is restarted later. If the profiler is not |
| // waiting, the increment will prevent it from waiting, but has to |
| // be undone after the profiler is stopped. |
| Atomic32 new_state = NoBarrier_AtomicIncrement(&state_, 1); |
| ASSERT(new_state >= 0); |
| if (new_state == 0) { |
| // The profiler thread is waiting. Wake it up. It must check for |
| // stop conditions before attempting to wait again. |
| semaphore.Pointer()->Signal(); |
| } |
| thread->Join(); |
| // The profiler thread is now stopped. Undo the increment in case it |
| // was not waiting. |
| if (new_state != 0) { |
| NoBarrier_AtomicIncrement(&state_, -1); |
| } |
| } |
| |
| |
| void RuntimeProfiler::RemoveDeadSamples() { |
| for (int i = 0; i < kSamplerWindowSize; i++) { |
| Object* function = sampler_window_[i]; |
| if (function != NULL && |
| !Marking::MarkBitFrom(HeapObject::cast(function)).Get()) { |
| sampler_window_[i] = NULL; |
| } |
| } |
| } |
| |
| |
| void RuntimeProfiler::UpdateSamplesAfterCompact(ObjectVisitor* visitor) { |
| for (int i = 0; i < kSamplerWindowSize; i++) { |
| visitor->VisitPointer(&sampler_window_[i]); |
| } |
| } |
| |
| |
| bool RuntimeProfilerRateLimiter::SuspendIfNecessary() { |
| if (!RuntimeProfiler::IsSomeIsolateInJS()) { |
| return RuntimeProfiler::WaitForSomeIsolateToEnterJS(); |
| } |
| return false; |
| } |
| |
| |
| } } // namespace v8::internal |