sampling-heap-profiler.cc | Explore in Territory

// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/profiler/sampling-heap-profiler.h"

#include <stdint.h>
#include <memory>

#include "src/api/api-inl.h"
#include "src/base/ieee754.h"
#include "src/base/utils/random-number-generator.h"
#include "src/execution/frames-inl.h"
#include "src/execution/isolate.h"
#include "src/heap/heap.h"
#include "src/profiler/strings-storage.h"

namespace v8 {
namespace internal {

// We sample with a Poisson process, with constant average sampling interval.
// This follows the exponential probability distribution with parameter
// λ = 1/rate where rate is the average number of bytes between samples.
//
// Let u be a uniformly distributed random number between 0 and 1, then
// next_sample = (- ln u) / λ
intptr_t SamplingHeapProfiler::Observer::GetNextSampleInterval(uint64_t rate) { … }

// Samples were collected according to a poisson process. Since we have not
// recorded all allocations, we must approximate the shape of the underlying
// space of allocations based on the samples we have collected. Given that
// we sample at rate R, the probability that an allocation of size S will be
// sampled is 1-exp(-S/R). This function uses the above probability to
// approximate the true number of allocations with size *size* given that
// *count* samples were observed.
v8::AllocationProfile::Allocation SamplingHeapProfiler::ScaleSample(
    size_t size, unsigned int count) const { … }

SamplingHeapProfiler::SamplingHeapProfiler(
    Heap* heap, StringsStorage* names, uint64_t rate, int stack_depth,
    v8::HeapProfiler::SamplingFlags flags)
    : … { … }

SamplingHeapProfiler::~SamplingHeapProfiler() { … }

void SamplingHeapProfiler::SampleObject(Address soon_object, size_t size) { … }

void SamplingHeapProfiler::OnWeakCallback(
    const WeakCallbackInfo<Sample>& data) { … }

SamplingHeapProfiler::AllocationNode* SamplingHeapProfiler::FindOrAddChildNode(
    AllocationNode* parent, const char* name, int script_id,
    int start_position) { … }

SamplingHeapProfiler::AllocationNode* SamplingHeapProfiler::AddStack() { … }

v8::AllocationProfile::Node* SamplingHeapProfiler::TranslateAllocationNode(
    AllocationProfile* profile, SamplingHeapProfiler::AllocationNode* node,
    const std::map<int, Handle<Script>>& scripts) { … }

v8::AllocationProfile* SamplingHeapProfiler::GetAllocationProfile() { … }

const std::vector<v8::AllocationProfile::Sample>
SamplingHeapProfiler::BuildSamples() const { … }

}  // namespace internal
}  // namespace v8
chromium/v8/src/profiler/sampling-heap-profiler.cc
