gecko-dev/tools/memory-profiler/MemoryProfiler.h

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3.9 KiB
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef tools_profiler_MemoryProfiler_h
#define tools_profiler_MemoryProfiler_h
#include "nsIMemoryProfiler.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/TimeStamp.h"
#include "CompactTraceTable.h"
#include "nsTArray.h"
#include "prlock.h"
#define MEMORY_PROFILER_CID \
{ 0xf976eaa2, 0xcc1f, 0x47ee, \
{ 0x81, 0x29, 0xb8, 0x26, 0x2a, 0x3d, 0xb6, 0xb2 } }
#define MEMORY_PROFILER_CONTRACT_ID "@mozilla.org/tools/memory-profiler;1"
struct PRLock;
namespace mozilla {
class NativeProfilerImpl;
class GCHeapProfilerImpl;
struct ProfilerForJSContext
{
ProfilerForJSContext()
: mProfiler(nullptr)
, mEnabled(false)
{}
GCHeapProfilerImpl* mProfiler;
bool mEnabled;
};
using JSContextProfilerMap =
nsDataHashtable<nsClearingPtrHashKey<JSContext>, ProfilerForJSContext>;
class MemoryProfiler final : public nsIMemoryProfiler
{
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIMEMORYPROFILER
private:
static void InitOnce();
~MemoryProfiler() {}
// The accesses to other static member are guarded by sLock and
// sProfileContextCount.
static PRLock* sLock;
static uint32_t sProfileContextCount;
static StaticAutoPtr<NativeProfilerImpl> sNativeProfiler;
static StaticAutoPtr<JSContextProfilerMap> sJSContextProfilerMap;
static TimeStamp sStartTime;
};
// Allocation events to be reported.
struct AllocEvent {
TimeStamp mTimestamp;
// index to a stacktrace singleton.
uint32_t mTraceIdx;
// Allocation size
int32_t mSize;
AllocEvent(uint32_t aTraceIdx, int32_t aSize, TimeStamp aTimestamp)
: mTimestamp(aTimestamp)
, mTraceIdx(aTraceIdx)
, mSize(aSize)
{}
};
// Index to allocation events but also a mark bit to be GC-able.
struct AllocEntry {
uint32_t mEventIdx : 31;
bool mMarked : 1;
// Default constructor for uninitialized stack value required by
// getter methods.
AllocEntry()
: mEventIdx(0)
, mMarked(false)
{}
explicit AllocEntry(int aEventIdx)
: mEventIdx(aEventIdx)
, mMarked(false)
{}
};
using AllocMap = nsDataHashtable<nsClearingVoidPtrHashKey, AllocEntry>;
class ProfilerImpl
{
public:
static nsTArray<nsCString> GetStacktrace();
static double DRandom();
ProfilerImpl();
virtual nsTArray<nsCString> GetNames() const = 0;
virtual nsTArray<TrieNode> GetTraces() const = 0;
virtual const nsTArray<AllocEvent>& GetEvents() const = 0;
protected:
/**
* The sampler generates a random variable which conforms to a geometric
* distribution of probability p = 1 / mSampleSize to calculate the
* next-to-be-sampled byte directly; It avoids rolling a dice on each byte.
*
* Let Bn denote a Bernoulli process with first success on n-th trial, the
* cumulative distribution function of Bn is Cn = 1 - (1 - p) ^ n.
* Let U denote a uniformly distributed random variable in [0, 1).
* A geometric random variable can be generated by Cn's reverse function:
* G = floor(log(1 - U) / log(1 - p)).
*
* @param aSize the number of bytes seen
* @return the number of events sampled
*/
size_t AddBytesSampled(uint32_t aBytes);
uint32_t mSampleSize;
private:
uint32_t mRemainingBytes;
double mLog1minusP;
};
/*
* This class is used to make sure the profile data is only accessed
* on one thread at a time. Don't use mozilla::Mutex because we don't
* want to allocate memory.
*/
class AutoMPLock
{
public:
explicit AutoMPLock(PRLock* aLock)
{
MOZ_ASSERT(aLock);
mLock = aLock;
PR_Lock(mLock);
}
~AutoMPLock()
{
PR_Unlock(mLock);
}
private:
PRLock* mLock;
};
} // namespace mozilla
#endif