[memory-infra] Implement peak detection logic

base/trace_event/memory_dump_scheduler.cc

 // 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_dump_scheduler.h"
 
+#include "base/process/process_metrics.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "build/build_config.h"
 
 namespace base {
 namespace trace_event {
 
 namespace {
 // Threshold on increase in memory from last dump beyond which a new dump must
 // be triggered.
-int64_t kMemoryIncreaseThreshold = 50 * 1024 * 1024;  // 50MiB
+int64_t kDefaultMemoryIncreaseThreshold = 50 * 1024 * 1024;  // 50MiB
 const uint32_t kMemoryTotalsPollingInterval = 25;
 uint32_t g_polling_interval_ms_for_testing = 0;
 }  // namespace
 
 MemoryDumpScheduler::MemoryDumpScheduler(
     MemoryDumpManager* mdm,
     scoped_refptr<SingleThreadTaskRunner> polling_task_runner)
     : mdm_(mdm), polling_state_(polling_task_runner) {}
 
 MemoryDumpScheduler::~MemoryDumpScheduler() {}
@@ skipping 49 matching lines @@
   periodic_state_.timer.Start(
       FROM_HERE,
       TimeDelta::FromMilliseconds(periodic_state_.min_timer_period_ms),
       Bind(&MemoryDumpScheduler::RequestPeriodicGlobalDump, Unretained(this)));
 }
 
 void MemoryDumpScheduler::NotifyPollingSupported() {
   if (!polling_state_.is_configured || polling_state_.is_polling_enabled)
     return;
   polling_state_.is_polling_enabled = true;
+  for (uint32_t i = 0; i < PollingTriggerState::kMaxNumMemorySamples; ++i)
+    polling_state_.last_memory_totals_kb[i] = 0;
+  polling_state_.last_memory_totals_kb_index = 0;
   polling_state_.num_polls_from_last_dump = 0;
   polling_state_.last_dump_memory_total = 0;
+
+  if (!polling_state_.memory_increase_threshold) {
+    polling_state_.memory_increase_threshold = kDefaultMemoryIncreaseThreshold;
+#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX) || \
+    defined(OS_ANDROID)
+    // Set threshold to 1% of total system memory.
+    SystemMemoryInfoKB meminfo;
+    bool res = GetSystemMemoryInfo(&meminfo);
+    if (res)
+      polling_state_.memory_increase_threshold = (meminfo.total / 100) * 1024;
+#endif
+  }
+
   polling_state_.polling_task_runner->PostTask(
       FROM_HERE,
       Bind(&MemoryDumpScheduler::PollMemoryOnPollingThread, Unretained(this)));
 }
 
 void MemoryDumpScheduler::DisableAllTriggers() {
   if (periodic_state_.timer.IsRunning())
     periodic_state_.timer.Stop();
   DisablePolling();
 }
@@ skipping 73 matching lines @@
   if (polling_state_.last_dump_memory_total == 0) {
     // If it's first sample then trigger memory dump.
     should_dump = true;
   } else if (polling_state_.min_polls_between_dumps >
              polling_state_.num_polls_from_last_dump) {
     return false;
   }
 
   int64_t increase_from_last_dump =
       current_memory_total - polling_state_.last_dump_memory_total;
-  should_dump |= increase_from_last_dump > kMemoryIncreaseThreshold;
+  should_dump |=
+      increase_from_last_dump > polling_state_.memory_increase_threshold;
+  should_dump |= IsCurrentSamplePeak(current_memory_total);
   if (should_dump) {
     polling_state_.last_dump_memory_total = current_memory_total;
     polling_state_.num_polls_from_last_dump = 0;
+    for (uint32_t i = 0; i < PollingTriggerState::kMaxNumMemorySamples; ++i)
+      polling_state_.last_memory_totals_kb[i] = 0;
+    polling_state_.last_memory_totals_kb_index = 0;
   }
   return should_dump;
 }
 
+bool MemoryDumpScheduler::IsCurrentSamplePeak(
+    uint64_t current_memory_total_bytes) {
+  uint64_t current_memory_total_kb = current_memory_total_bytes / 1024;
+  polling_state_.last_memory_totals_kb_index =
+      (polling_state_.last_memory_totals_kb_index + 1) %
+      PollingTriggerState::kMaxNumMemorySamples;
+  uint64_t mean = 0;
+  for (uint32_t i = 0; i < PollingTriggerState::kMaxNumMemorySamples; ++i) {
+    if (polling_state_.last_memory_totals_kb[i] == 0) {
+      // Not enough samples to detect peaks.
+      polling_state_
+          .last_memory_totals_kb[polling_state_.last_memory_totals_kb_index] =
+          current_memory_total_kb;
+      return false;
+    }
+    mean += polling_state_.last_memory_totals_kb[i];
+  }
+  mean = mean / PollingTriggerState::kMaxNumMemorySamples;
+  uint64_t variance = 0;
+  for (uint32_t i = 0; i < PollingTriggerState::kMaxNumMemorySamples; ++i) {
+    variance += (polling_state_.last_memory_totals_kb[i] - mean) *
+                (polling_state_.last_memory_totals_kb[i] - mean);
+  }
+  variance = variance / PollingTriggerState::kMaxNumMemorySamples;
+
+  polling_state_
+      .last_memory_totals_kb[polling_state_.last_memory_totals_kb_index] =
+      current_memory_total_kb;
+
+  // If stddev is less than 0.2% then we consider that the process is inactive.
+  bool is_stddev_low = variance < mean / 500 * mean / 500;
+  if (is_stddev_low)
+    return false;
+
+  // (mean + 3.69 * stddev) corresponds to a value that is higher than current
+  // sample with 99.99% probability.
+  return (current_memory_total_kb - mean) * (current_memory_total_kb - mean) >
+         (3.69 * 3.69 * variance);
+}
+
 MemoryDumpScheduler::PeriodicTriggerState::PeriodicTriggerState()
     : is_configured(false),
       dump_count(0),
       min_timer_period_ms(std::numeric_limits<uint32_t>::max()),
       light_dumps_rate(0),
       heavy_dumps_rate(0),
       light_dump_period_ms(0),
       heavy_dump_period_ms(0) {}
 
 MemoryDumpScheduler::PeriodicTriggerState::~PeriodicTriggerState() {
   DCHECK(!timer.IsRunning());
 }
 
 MemoryDumpScheduler::PollingTriggerState::PollingTriggerState(
     scoped_refptr<SingleThreadTaskRunner> polling_task_runner)
     : is_configured(false),
       is_polling_enabled(false),
       level_of_detail(MemoryDumpLevelOfDetail::FIRST),
       polling_task_runner(polling_task_runner),
       polling_interval_ms(g_polling_interval_ms_for_testing
                               ? g_polling_interval_ms_for_testing
                               : kMemoryTotalsPollingInterval),
       min_polls_between_dumps(0),
       num_polls_from_last_dump(0),
-      last_dump_memory_total(0) {}
+      last_dump_memory_total(0),
+      memory_increase_threshold(0),
+      last_memory_totals_kb_index(0) {}
 
 MemoryDumpScheduler::PollingTriggerState::~PollingTriggerState() {
   DCHECK(!polling_task_runner);
 }
 
 }  // namespace trace_event
 }  // namespace base