0177aa62da
Hidden behind --type-info-threshold=X flag, usage dependent on experimental profiler. Review URL: https://chromiumcodereview.appspot.com/9403009 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10753 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
475 lines
16 KiB
C++
475 lines
16 KiB
C++
// Copyright 2012 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "v8.h"
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#include "runtime-profiler.h"
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#include "assembler.h"
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#include "code-stubs.h"
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#include "compilation-cache.h"
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#include "deoptimizer.h"
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#include "execution.h"
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#include "global-handles.h"
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#include "isolate-inl.h"
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#include "mark-compact.h"
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#include "platform.h"
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#include "scopeinfo.h"
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namespace v8 {
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namespace internal {
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// Optimization sampler constants.
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static const int kSamplerFrameCount = 2;
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// Constants for statistical profiler.
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static const int kSamplerFrameWeight[kSamplerFrameCount] = { 2, 1 };
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static const int kSamplerTicksBetweenThresholdAdjustment = 32;
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static const int kSamplerThresholdInit = 3;
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static const int kSamplerThresholdMin = 1;
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static const int kSamplerThresholdDelta = 1;
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static const int kSamplerThresholdSizeFactorInit = 3;
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static const int kSizeLimit = 1500;
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// Constants for counter based profiler.
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// Number of times a function has to be seen on the stack before it is
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// optimized.
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static const int kProfilerTicksBeforeOptimization = 2;
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// Maximum size in bytes of generated code for a function to be optimized
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// the very first time it is seen on the stack.
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static const int kMaxSizeEarlyOpt = 500;
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Atomic32 RuntimeProfiler::state_ = 0;
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// TODO(isolates): Create the semaphore lazily and clean it up when no
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// longer required.
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Semaphore* RuntimeProfiler::semaphore_ = OS::CreateSemaphore(0);
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#ifdef DEBUG
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bool RuntimeProfiler::has_been_globally_set_up_ = false;
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#endif
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bool RuntimeProfiler::enabled_ = false;
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RuntimeProfiler::RuntimeProfiler(Isolate* isolate)
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: isolate_(isolate),
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sampler_threshold_(kSamplerThresholdInit),
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sampler_threshold_size_factor_(kSamplerThresholdSizeFactorInit),
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sampler_ticks_until_threshold_adjustment_(
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kSamplerTicksBetweenThresholdAdjustment),
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sampler_window_position_(0) {
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ClearSampleBuffer();
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}
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void RuntimeProfiler::GlobalSetup() {
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ASSERT(!has_been_globally_set_up_);
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enabled_ = V8::UseCrankshaft() && FLAG_opt;
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#ifdef DEBUG
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has_been_globally_set_up_ = true;
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#endif
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}
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static void GetICCounts(JSFunction* function,
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int* ic_with_typeinfo_count,
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int* ic_total_count,
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int* percentage) {
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*ic_total_count = 0;
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*ic_with_typeinfo_count = 0;
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Object* raw_info =
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function->shared()->code()->type_feedback_info();
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if (raw_info->IsTypeFeedbackInfo()) {
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TypeFeedbackInfo* info = TypeFeedbackInfo::cast(raw_info);
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*ic_with_typeinfo_count = info->ic_with_typeinfo_count();
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*ic_total_count = info->ic_total_count();
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}
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*percentage = *ic_total_count > 0
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? 100 * *ic_with_typeinfo_count / *ic_total_count
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: 100;
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}
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void RuntimeProfiler::Optimize(JSFunction* function, const char* reason) {
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ASSERT(function->IsOptimizable());
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if (FLAG_trace_opt) {
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PrintF("[marking ");
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function->PrintName();
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PrintF(" 0x%" V8PRIxPTR, reinterpret_cast<intptr_t>(function->address()));
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PrintF(" for recompilation, reason: %s", reason);
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if (FLAG_type_info_threshold > 0) {
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int typeinfo, total, percentage;
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GetICCounts(function, &typeinfo, &total, &percentage);
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PrintF(", ICs with typeinfo: %d/%d (%d%%)", typeinfo, total, percentage);
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}
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PrintF("]\n");
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}
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// The next call to the function will trigger optimization.
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function->MarkForLazyRecompilation();
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}
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void RuntimeProfiler::AttemptOnStackReplacement(JSFunction* function) {
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// See AlwaysFullCompiler (in compiler.cc) comment on why we need
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// Debug::has_break_points().
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ASSERT(function->IsMarkedForLazyRecompilation());
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if (!FLAG_use_osr ||
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isolate_->DebuggerHasBreakPoints() ||
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function->IsBuiltin()) {
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return;
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}
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SharedFunctionInfo* shared = function->shared();
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// If the code is not optimizable, don't try OSR.
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if (!shared->code()->optimizable()) return;
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// We are not prepared to do OSR for a function that already has an
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// allocated arguments object. The optimized code would bypass it for
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// arguments accesses, which is unsound. Don't try OSR.
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if (shared->uses_arguments()) return;
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// We're using on-stack replacement: patch the unoptimized code so that
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// any back edge in any unoptimized frame will trigger on-stack
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// replacement for that frame.
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if (FLAG_trace_osr) {
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PrintF("[patching stack checks in ");
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function->PrintName();
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PrintF(" for on-stack replacement]\n");
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}
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// Get the stack check stub code object to match against. We aren't
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// prepared to generate it, but we don't expect to have to.
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bool found_code = false;
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Code* stack_check_code = NULL;
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#ifdef V8_TARGET_ARCH_IA32
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if (FLAG_count_based_interrupts) {
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InterruptStub interrupt_stub;
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found_code = interrupt_stub.FindCodeInCache(&stack_check_code);
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} else // NOLINT
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#endif
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{ // NOLINT
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StackCheckStub check_stub;
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found_code = check_stub.FindCodeInCache(&stack_check_code);
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}
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if (found_code) {
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Code* replacement_code =
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isolate_->builtins()->builtin(Builtins::kOnStackReplacement);
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Code* unoptimized_code = shared->code();
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Deoptimizer::PatchStackCheckCode(unoptimized_code,
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stack_check_code,
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replacement_code);
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}
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}
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void RuntimeProfiler::ClearSampleBuffer() {
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memset(sampler_window_, 0, sizeof(sampler_window_));
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memset(sampler_window_weight_, 0, sizeof(sampler_window_weight_));
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}
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int RuntimeProfiler::LookupSample(JSFunction* function) {
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int weight = 0;
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for (int i = 0; i < kSamplerWindowSize; i++) {
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Object* sample = sampler_window_[i];
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if (sample != NULL) {
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if (function == sample) {
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weight += sampler_window_weight_[i];
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}
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}
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}
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return weight;
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}
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void RuntimeProfiler::AddSample(JSFunction* function, int weight) {
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ASSERT(IsPowerOf2(kSamplerWindowSize));
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sampler_window_[sampler_window_position_] = function;
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sampler_window_weight_[sampler_window_position_] = weight;
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sampler_window_position_ = (sampler_window_position_ + 1) &
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(kSamplerWindowSize - 1);
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}
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void RuntimeProfiler::OptimizeNow() {
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HandleScope scope(isolate_);
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// Run through the JavaScript frames and collect them. If we already
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// have a sample of the function, we mark it for optimizations
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// (eagerly or lazily).
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JSFunction* samples[kSamplerFrameCount];
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int sample_count = 0;
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int frame_count = 0;
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int frame_count_limit = FLAG_watch_ic_patching ? FLAG_frame_count
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: kSamplerFrameCount;
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for (JavaScriptFrameIterator it(isolate_);
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frame_count++ < frame_count_limit && !it.done();
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it.Advance()) {
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JavaScriptFrame* frame = it.frame();
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JSFunction* function = JSFunction::cast(frame->function());
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if (!FLAG_watch_ic_patching) {
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// Adjust threshold each time we have processed
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// a certain number of ticks.
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if (sampler_ticks_until_threshold_adjustment_ > 0) {
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sampler_ticks_until_threshold_adjustment_--;
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if (sampler_ticks_until_threshold_adjustment_ <= 0) {
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// If the threshold is not already at the minimum
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// modify and reset the ticks until next adjustment.
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if (sampler_threshold_ > kSamplerThresholdMin) {
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sampler_threshold_ -= kSamplerThresholdDelta;
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sampler_ticks_until_threshold_adjustment_ =
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kSamplerTicksBetweenThresholdAdjustment;
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}
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}
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}
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}
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if (function->IsMarkedForLazyRecompilation()) {
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Code* unoptimized = function->shared()->code();
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int nesting = unoptimized->allow_osr_at_loop_nesting_level();
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if (nesting == 0) AttemptOnStackReplacement(function);
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int new_nesting = Min(nesting + 1, Code::kMaxLoopNestingMarker);
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unoptimized->set_allow_osr_at_loop_nesting_level(new_nesting);
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}
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// Do not record non-optimizable functions.
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if (!function->IsOptimizable()) continue;
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// Only record top-level code on top of the execution stack and
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// avoid optimizing excessively large scripts since top-level code
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// will be executed only once.
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const int kMaxToplevelSourceSize = 10 * 1024;
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if (function->shared()->is_toplevel()
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&& (frame_count > 1
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|| function->shared()->SourceSize() > kMaxToplevelSourceSize)) {
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continue;
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}
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if (FLAG_watch_ic_patching) {
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int ticks = function->shared()->profiler_ticks();
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if (ticks >= kProfilerTicksBeforeOptimization) {
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int typeinfo, total, percentage;
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GetICCounts(function, &typeinfo, &total, &percentage);
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if (percentage >= FLAG_type_info_threshold) {
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// If this particular function hasn't had any ICs patched for enough
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// ticks, optimize it now.
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Optimize(function, "hot and stable");
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} else {
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if (FLAG_trace_opt_verbose) {
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PrintF("[not yet optimizing ");
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function->PrintName();
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PrintF(", not enough type info: %d/%d (%d%%)]\n",
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typeinfo, total, percentage);
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}
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}
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} else if (!any_ic_changed_ &&
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function->shared()->code()->instruction_size() < kMaxSizeEarlyOpt) {
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// If no IC was patched since the last tick and this function is very
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// small, optimistically optimize it now.
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Optimize(function, "small function");
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} else if (!code_generated_ &&
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!any_ic_changed_ &&
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total_code_generated_ > 0 &&
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total_code_generated_ < 2000) {
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// If no code was generated and no IC was patched since the last tick,
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// but a little code has already been generated since last Reset(),
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// then type info might already be stable and we can optimize now.
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Optimize(function, "stable on startup");
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} else {
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function->shared()->set_profiler_ticks(ticks + 1);
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}
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} else { // !FLAG_watch_ic_patching
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samples[sample_count++] = function;
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int function_size = function->shared()->SourceSize();
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int threshold_size_factor = (function_size > kSizeLimit)
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? sampler_threshold_size_factor_
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: 1;
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int threshold = sampler_threshold_ * threshold_size_factor;
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if (LookupSample(function) >= threshold) {
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Optimize(function, "sampler window lookup");
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}
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}
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}
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if (FLAG_watch_ic_patching) {
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any_ic_changed_ = false;
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code_generated_ = false;
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} else { // !FLAG_watch_ic_patching
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// Add the collected functions as samples. It's important not to do
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// this as part of collecting them because this will interfere with
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// the sample lookup in case of recursive functions.
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for (int i = 0; i < sample_count; i++) {
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AddSample(samples[i], kSamplerFrameWeight[i]);
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}
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}
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}
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void RuntimeProfiler::NotifyTick() {
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#ifdef V8_TARGET_ARCH_IA32
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if (FLAG_count_based_interrupts) return;
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#endif
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isolate_->stack_guard()->RequestRuntimeProfilerTick();
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}
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void RuntimeProfiler::SetUp() {
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ASSERT(has_been_globally_set_up_);
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if (!FLAG_watch_ic_patching) {
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ClearSampleBuffer();
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}
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// If the ticker hasn't already started, make sure to do so to get
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// the ticks for the runtime profiler.
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if (IsEnabled()) isolate_->logger()->EnsureTickerStarted();
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}
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void RuntimeProfiler::Reset() {
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if (FLAG_watch_ic_patching) {
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total_code_generated_ = 0;
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} else { // !FLAG_watch_ic_patching
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sampler_threshold_ = kSamplerThresholdInit;
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sampler_threshold_size_factor_ = kSamplerThresholdSizeFactorInit;
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sampler_ticks_until_threshold_adjustment_ =
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kSamplerTicksBetweenThresholdAdjustment;
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}
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}
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void RuntimeProfiler::TearDown() {
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// Nothing to do.
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}
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int RuntimeProfiler::SamplerWindowSize() {
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return kSamplerWindowSize;
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}
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// Update the pointers in the sampler window after a GC.
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void RuntimeProfiler::UpdateSamplesAfterScavenge() {
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for (int i = 0; i < kSamplerWindowSize; i++) {
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Object* function = sampler_window_[i];
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if (function != NULL && isolate_->heap()->InNewSpace(function)) {
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MapWord map_word = HeapObject::cast(function)->map_word();
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if (map_word.IsForwardingAddress()) {
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sampler_window_[i] = map_word.ToForwardingAddress();
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} else {
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sampler_window_[i] = NULL;
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}
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}
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}
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}
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void RuntimeProfiler::HandleWakeUp(Isolate* isolate) {
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// The profiler thread must still be waiting.
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ASSERT(NoBarrier_Load(&state_) >= 0);
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// In IsolateEnteredJS we have already incremented the counter and
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// undid the decrement done by the profiler thread. Increment again
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// to get the right count of active isolates.
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NoBarrier_AtomicIncrement(&state_, 1);
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semaphore_->Signal();
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}
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bool RuntimeProfiler::IsSomeIsolateInJS() {
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return NoBarrier_Load(&state_) > 0;
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}
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bool RuntimeProfiler::WaitForSomeIsolateToEnterJS() {
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Atomic32 old_state = NoBarrier_CompareAndSwap(&state_, 0, -1);
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ASSERT(old_state >= -1);
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if (old_state != 0) return false;
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semaphore_->Wait();
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return true;
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}
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void RuntimeProfiler::StopRuntimeProfilerThreadBeforeShutdown(Thread* thread) {
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// Do a fake increment. If the profiler is waiting on the semaphore,
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// the returned state is 0, which can be left as an initial state in
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// case profiling is restarted later. If the profiler is not
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// waiting, the increment will prevent it from waiting, but has to
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// be undone after the profiler is stopped.
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Atomic32 new_state = NoBarrier_AtomicIncrement(&state_, 1);
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ASSERT(new_state >= 0);
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if (new_state == 0) {
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// The profiler thread is waiting. Wake it up. It must check for
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// stop conditions before attempting to wait again.
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semaphore_->Signal();
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}
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thread->Join();
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// The profiler thread is now stopped. Undo the increment in case it
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// was not waiting.
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if (new_state != 0) {
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NoBarrier_AtomicIncrement(&state_, -1);
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}
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}
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void RuntimeProfiler::RemoveDeadSamples() {
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for (int i = 0; i < kSamplerWindowSize; i++) {
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Object* function = sampler_window_[i];
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if (function != NULL &&
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!Marking::MarkBitFrom(HeapObject::cast(function)).Get()) {
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sampler_window_[i] = NULL;
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}
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}
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}
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void RuntimeProfiler::UpdateSamplesAfterCompact(ObjectVisitor* visitor) {
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for (int i = 0; i < kSamplerWindowSize; i++) {
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visitor->VisitPointer(&sampler_window_[i]);
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}
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}
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bool RuntimeProfilerRateLimiter::SuspendIfNecessary() {
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if (!RuntimeProfiler::IsSomeIsolateInJS()) {
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return RuntimeProfiler::WaitForSomeIsolateToEnterJS();
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}
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return false;
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}
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} } // namespace v8::internal
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