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memory_peak_detector.cc
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memory_peak_detector.cc
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// Copyright 2017 The Chromium 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 "base/trace_event/memory_peak_detector.h"
#include <algorithm>
#include "base/bind.h"
#include "base/logging.h"
#include "base/sys_info.h"
#include "base/threading/sequenced_task_runner_handle.h"
#include "base/time/time.h"
#include "base/trace_event/memory_dump_manager.h"
#include "base/trace_event/memory_dump_provider_info.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
namespace base {
namespace trace_event {
// static
MemoryPeakDetector* MemoryPeakDetector::GetInstance() {
static MemoryPeakDetector* instance = new MemoryPeakDetector();
return instance;
}
MemoryPeakDetector::MemoryPeakDetector()
: generation_(0),
state_(NOT_INITIALIZED),
poll_tasks_count_for_testing_(0) {}
MemoryPeakDetector::~MemoryPeakDetector() {
// This is hit only in tests, in which case the test is expected to TearDown()
// cleanly and not leave the peak detector running.
DCHECK_EQ(NOT_INITIALIZED, state_);
}
void MemoryPeakDetector::Setup(
const GetDumpProvidersFunction& get_dump_providers_function,
const scoped_refptr<SequencedTaskRunner>& task_runner,
const OnPeakDetectedCallback& on_peak_detected_callback) {
DCHECK(!get_dump_providers_function.is_null());
DCHECK(task_runner);
DCHECK(!on_peak_detected_callback.is_null());
DCHECK(state_ == NOT_INITIALIZED || state_ == DISABLED);
DCHECK(dump_providers_.empty());
get_dump_providers_function_ = get_dump_providers_function;
task_runner_ = task_runner;
on_peak_detected_callback_ = on_peak_detected_callback;
state_ = DISABLED;
config_ = {};
ResetPollHistory();
static_threshold_bytes_ = 0;
#if !defined(OS_NACL)
// Set threshold to 1% of total system memory.
static_threshold_bytes_ =
static_cast<uint64_t>(SysInfo::AmountOfPhysicalMemory()) / 100;
#endif
// Fallback, mostly for test environments where AmountOfPhysicalMemory() is
// broken.
static_threshold_bytes_ =
std::max(static_threshold_bytes_, static_cast<uint64_t>(5 * 1024 * 1024));
}
void MemoryPeakDetector::TearDown() {
if (task_runner_) {
task_runner_->PostTask(
FROM_HERE,
BindOnce(&MemoryPeakDetector::TearDownInternal, Unretained(this)));
}
task_runner_ = nullptr;
}
void MemoryPeakDetector::Start(MemoryPeakDetector::Config config) {
if (!config.polling_interval_ms) {
NOTREACHED();
return;
}
task_runner_->PostTask(FROM_HERE, BindOnce(&MemoryPeakDetector::StartInternal,
Unretained(this), config));
}
void MemoryPeakDetector::Stop() {
task_runner_->PostTask(
FROM_HERE, BindOnce(&MemoryPeakDetector::StopInternal, Unretained(this)));
}
void MemoryPeakDetector::Throttle() {
if (!task_runner_)
return; // Can be called before Setup().
task_runner_->PostTask(
FROM_HERE, BindOnce(&MemoryPeakDetector::ResetPollHistory,
Unretained(this), true /* keep_last_sample */));
}
void MemoryPeakDetector::NotifyMemoryDumpProvidersChanged() {
if (!task_runner_)
return; // Can be called before Setup().
task_runner_->PostTask(
FROM_HERE,
BindOnce(&MemoryPeakDetector::ReloadDumpProvidersAndStartPollingIfNeeded,
Unretained(this)));
}
void MemoryPeakDetector::StartInternal(MemoryPeakDetector::Config config) {
DCHECK_EQ(DISABLED, state_);
state_ = ENABLED;
config_ = config;
ResetPollHistory();
// If there are any dump providers available,
// NotifyMemoryDumpProvidersChanged will fetch them and start the polling.
// Otherwise this will remain in the ENABLED state and the actual polling
// will start on the next call to
// ReloadDumpProvidersAndStartPollingIfNeeded().
// Depending on the sandbox model, it is possible that no polling-capable
// dump providers will be ever available.
ReloadDumpProvidersAndStartPollingIfNeeded();
}
void MemoryPeakDetector::StopInternal() {
DCHECK_NE(NOT_INITIALIZED, state_);
state_ = DISABLED;
++generation_;
for (const scoped_refptr<MemoryDumpProviderInfo>& mdp_info : dump_providers_)
mdp_info->dump_provider->SuspendFastMemoryPolling();
dump_providers_.clear();
}
void MemoryPeakDetector::TearDownInternal() {
StopInternal();
get_dump_providers_function_.Reset();
on_peak_detected_callback_.Reset();
state_ = NOT_INITIALIZED;
}
void MemoryPeakDetector::ReloadDumpProvidersAndStartPollingIfNeeded() {
if (state_ == DISABLED || state_ == NOT_INITIALIZED)
return; // Start() will re-fetch the MDP list later.
DCHECK((state_ == RUNNING && !dump_providers_.empty()) ||
(state_ == ENABLED && dump_providers_.empty()));
dump_providers_.clear();
// This is really MemoryDumpManager::GetDumpProvidersForPolling, % testing.
get_dump_providers_function_.Run(&dump_providers_);
if (state_ == ENABLED && !dump_providers_.empty()) {
// It's now time to start polling for realz.
state_ = RUNNING;
task_runner_->PostTask(
FROM_HERE, BindOnce(&MemoryPeakDetector::PollMemoryAndDetectPeak,
Unretained(this), ++generation_));
} else if (state_ == RUNNING && dump_providers_.empty()) {
// Will cause the next PollMemoryAndDetectPeak() task to early return.
state_ = ENABLED;
++generation_;
}
}
void MemoryPeakDetector::PollMemoryAndDetectPeak(uint32_t expected_generation) {
if (state_ != RUNNING || generation_ != expected_generation)
return;
// We should never end up in a situation where state_ == RUNNING but all dump
// providers are gone.
DCHECK(!dump_providers_.empty());
poll_tasks_count_for_testing_++;
uint64_t polled_mem_bytes = 0;
for (const scoped_refptr<MemoryDumpProviderInfo>& mdp_info :
dump_providers_) {
DCHECK(mdp_info->options.is_fast_polling_supported);
uint64_t value = 0;
mdp_info->dump_provider->PollFastMemoryTotal(&value);
polled_mem_bytes += value;
}
if (config_.enable_verbose_poll_tracing) {
TRACE_COUNTER1(MemoryDumpManager::kTraceCategory, "PolledMemoryMB",
polled_mem_bytes / 1024 / 1024);
}
// Peak detection logic. Design doc: https://goo.gl/0kOU4A .
bool is_peak = false;
if (skip_polls_ > 0) {
skip_polls_--;
} else if (last_dump_memory_total_ == 0) {
last_dump_memory_total_ = polled_mem_bytes;
} else if (polled_mem_bytes > 0) {
int64_t diff_from_last_dump = polled_mem_bytes - last_dump_memory_total_;
DCHECK_GT(static_threshold_bytes_, 0u);
is_peak =
diff_from_last_dump > static_cast<int64_t>(static_threshold_bytes_);
if (!is_peak)
is_peak = DetectPeakUsingSlidingWindowStddev(polled_mem_bytes);
}
DCHECK_GT(config_.polling_interval_ms, 0u);
SequencedTaskRunnerHandle::Get()->PostDelayedTask(
FROM_HERE,
BindOnce(&MemoryPeakDetector::PollMemoryAndDetectPeak, Unretained(this),
expected_generation),
TimeDelta::FromMilliseconds(config_.polling_interval_ms));
if (!is_peak)
return;
TRACE_EVENT_INSTANT1(MemoryDumpManager::kTraceCategory,
"Peak memory detected", TRACE_EVENT_SCOPE_PROCESS,
"PolledMemoryMB", polled_mem_bytes / 1024 / 1024);
ResetPollHistory(true /* keep_last_sample */);
last_dump_memory_total_ = polled_mem_bytes;
on_peak_detected_callback_.Run();
}
bool MemoryPeakDetector::DetectPeakUsingSlidingWindowStddev(
uint64_t polled_mem_bytes) {
DCHECK(polled_mem_bytes);
samples_bytes_[samples_index_] = polled_mem_bytes;
samples_index_ = (samples_index_ + 1) % kSlidingWindowNumSamples;
float mean = 0;
for (uint32_t i = 0; i < kSlidingWindowNumSamples; ++i) {
if (samples_bytes_[i] == 0)
return false; // Not enough samples to detect peaks.
mean += samples_bytes_[i];
}
mean /= kSlidingWindowNumSamples;
float variance = 0;
for (uint32_t i = 0; i < kSlidingWindowNumSamples; ++i) {
const float deviation = samples_bytes_[i] - mean;
variance += deviation * deviation;
}
variance /= kSlidingWindowNumSamples;
// If stddev is less than 0.2% then we consider that the process is inactive.
if (variance < (mean / 500) * (mean / 500))
return false;
// (mean + 3.69 * stddev) corresponds to a value that is higher than current
// sample with 99.99% probability.
const float cur_sample_deviation = polled_mem_bytes - mean;
return cur_sample_deviation * cur_sample_deviation > (3.69 * 3.69 * variance);
}
void MemoryPeakDetector::ResetPollHistory(bool keep_last_sample) {
// TODO(primiano,ssid): this logic should probably be revisited. In the case
// of Android, the browser process sees the total of all processes memory in
// the same peak detector instance. Perhaps the best thing to do here is to
// keep the window of samples around and just bump the skip_polls_.
last_dump_memory_total_ = 0;
if (keep_last_sample) {
const uint32_t prev_index =
samples_index_ > 0 ? samples_index_ - 1 : kSlidingWindowNumSamples - 1;
last_dump_memory_total_ = samples_bytes_[prev_index];
}
memset(samples_bytes_, 0, sizeof(samples_bytes_));
samples_index_ = 0;
skip_polls_ = 0;
if (config_.polling_interval_ms > 0) {
skip_polls_ =
(config_.min_time_between_peaks_ms + config_.polling_interval_ms - 1) /
config_.polling_interval_ms;
}
}
void MemoryPeakDetector::SetStaticThresholdForTesting(
uint64_t static_threshold_bytes) {
DCHECK_EQ(DISABLED, state_);
static_threshold_bytes_ = static_threshold_bytes;
}
MemoryPeakDetector::MemoryPeakDetector::Config::Config()
: Config(0, 0, false) {}
MemoryPeakDetector::MemoryPeakDetector::Config::Config(
uint32_t polling_interval_ms,
uint32_t min_time_between_peaks_ms,
bool enable_verbose_poll_tracing)
: polling_interval_ms(polling_interval_ms),
min_time_between_peaks_ms(min_time_between_peaks_ms),
enable_verbose_poll_tracing(enable_verbose_poll_tracing) {}
} // namespace trace_event
} // namespace base