Updated device reporting code to report multiple samples of free RAM

DeviceStatusCollector used to report multiple CPU usage measurements, but only a
single free-RAM measurement. This CL changes the reporting code to report
multiple free-RAM measurements.

BUG=430908

Review URL: https://codereview.chromium.org/884063003

Cr-Commit-Position: refs/heads/master@{#313681}

chrome/browser/chromeos/policy/device_status_collector.cc

@@ -353,7 +353,7 @@ void DeviceStatusCollector::AddActivePeriod(Time start, Time end) {
 
 void DeviceStatusCollector::ClearCachedHardwareStatus() {
   volume_info_.clear();
-  cpu_usage_percent_.clear();
+  resource_usage_.clear();
 }
 
 void DeviceStatusCollector::IdleStateCallback(ui::IdleState state) {
@@ -402,22 +402,26 @@ void DeviceStatusCollector::SampleHardwareStatus() {
       base::Bind(&DeviceStatusCollector::ReceiveVolumeInfo,
                  weak_factory_.GetWeakPtr()));
 
-  SampleCPUUsage();
+  SampleResourceUsage();
 }
 
-void DeviceStatusCollector::SampleCPUUsage() {
+void DeviceStatusCollector::SampleResourceUsage() {
   // Walk the process list and measure CPU utilization.
   double total_usage = 0;
   std::vector<double> per_process_usage = GetPerProcessCPUUsage();
   for (double cpu_usage : per_process_usage) {
     total_usage += cpu_usage;
   }
-  cpu_usage_percent_.push_back(total_usage);
+
+  ResourceUsage usage = { total_usage,
+                          base::SysInfo::AmountOfAvailablePhysicalMemory() };
+
+  resource_usage_.push_back(usage);
 
   // If our cache of samples is full, throw out old samples to make room for new
   // sample.
-  if (cpu_usage_percent_.size() > kMaxCPUSamples)
-    cpu_usage_percent_.pop_front();
+  if (resource_usage_.size() > kMaxResourceUsageSamples)
+    resource_usage_.pop_front();
 }
 
 std::vector<double> DeviceStatusCollector::GetPerProcessCPUUsage() {
@@ -654,12 +658,12 @@ void DeviceStatusCollector::GetHardwareStatus(
     *status->add_volume_info() = info;
   }
 
-  status->set_system_ram_free(base::SysInfo::AmountOfAvailablePhysicalMemory());
   status->set_system_ram_total(base::SysInfo::AmountOfPhysicalMemory());
-
+  status->clear_system_ram_free();
   status->clear_cpu_utilization_pct();
-  for (const int cpu_usage : cpu_usage_percent_) {
-    status->add_cpu_utilization_pct(cpu_usage);
+  for (const ResourceUsage& usage : resource_usage_) {
+    status->add_cpu_utilization_pct(usage.cpu_usage_percent);
+    status->add_system_ram_free(usage.bytes_of_ram_free);
   }
 }
 

chrome/browser/chromeos/policy/device_status_collector.h

@@ -86,8 +86,8 @@ class DeviceStatusCollector {
   // How often, in seconds, to poll to see if the user is idle.
   static const unsigned int kIdlePollIntervalSeconds = 30;
 
-  // The total number of CPU samples cached internally.
-  static const unsigned int kMaxCPUSamples = 10;
+  // The total number of hardware resource usage samples cached internally.
+  static const unsigned int kMaxResourceUsageSamples = 10;
 
  protected:
   // Check whether the user has been idle for a certain period of time.
@@ -99,8 +99,8 @@ class DeviceStatusCollector {
   // Callback which receives the results of the idle state check.
   void IdleStateCallback(ui::IdleState state);
 
-  // Samples the current CPU usage and updates our cache of samples.
-  void SampleCPUUsage();
+  // Samples the current CPU and RAM usage and updates our cache of samples.
+  void SampleResourceUsage();
 
   // Returns the percentage of total CPU that each process uses. Virtual so it
   // can be mocked.
@@ -195,9 +195,18 @@ class DeviceStatusCollector {
   // Cached disk volume information.
   std::vector<enterprise_management::VolumeInfo> volume_info_;
 
-  // Cached percentage-of-CPU-used data (contains multiple samples taken
+  struct ResourceUsage {
+    // Sample of percentage-of-CPU-used across all processes (0-100)
+    int cpu_usage_percent;
+
+    // Amount of free RAM (measures raw memory used by processes, not internal
+    // memory waiting to be reclaimed by GC).
+    int64 bytes_of_ram_free;
+  };
+
+  // Samples of resource usage (contains multiple samples taken
   // periodically every kHardwareStatusSampleIntervalSeconds).
-  std::deque<int> cpu_usage_percent_;
+  std::deque<ResourceUsage> resource_usage_;
 
   // Callback invoked to fetch information about the mounted disk volumes.
   VolumeInfoFetcher volume_info_fetcher_;

chrome/browser/chromeos/policy/device_status_collector_browsertest.cc

@@ -125,9 +125,14 @@ class TestingDeviceStatusCollector : public policy::DeviceStatusCollector {
 
     mock_cpu_usage_ = usage;
 
-    // Refresh our samples.
-    for (int i = 0; i < static_cast<int>(kMaxCPUSamples); ++i)
-      SampleCPUUsage();
+    RefreshSampleResourceUsage();
+  }
+
+  void RefreshSampleResourceUsage() {
+    // Refresh our samples. Sample more than kMaxHardwareSamples times to
+    // make sure that the code correctly caps the number of cached samples.
+    for (int i = 0; i < static_cast<int>(kMaxResourceUsageSamples + 1); ++i)
+      SampleResourceUsage();
   }
 
  protected:
@@ -790,8 +795,10 @@ TEST_F(DeviceStatusCollectorTest, TestVolumeInfo) {
 }
 
 TEST_F(DeviceStatusCollectorTest, TestAvailableMemory) {
+  status_collector_->RefreshSampleResourceUsage();
   GetStatus();
-  EXPECT_TRUE(status_.has_system_ram_free());
+  EXPECT_EQ(static_cast<int>(DeviceStatusCollector::kMaxResourceUsageSamples),
+            status_.system_ram_free().size());
   EXPECT_TRUE(status_.has_system_ram_total());
   // No good way to inject specific test values for available system RAM, so
   // just make sure it's > 0.
@@ -803,7 +810,7 @@ TEST_F(DeviceStatusCollectorTest, TestCPUSamples) {
   const int full_cpu_usage = 100;
   status_collector_->set_mock_cpu_usage(full_cpu_usage, 2);
   GetStatus();
-  EXPECT_EQ(static_cast<int>(DeviceStatusCollector::kMaxCPUSamples),
+  EXPECT_EQ(static_cast<int>(DeviceStatusCollector::kMaxResourceUsageSamples),
             status_.cpu_utilization_pct().size());
   for (const auto utilization : status_.cpu_utilization_pct())
     EXPECT_EQ(full_cpu_usage, utilization);
@@ -812,7 +819,7 @@ TEST_F(DeviceStatusCollectorTest, TestCPUSamples) {
   const int idle_cpu_usage = 0;
   status_collector_->set_mock_cpu_usage(idle_cpu_usage, 2);
   GetStatus();
-  EXPECT_EQ(static_cast<int>(DeviceStatusCollector::kMaxCPUSamples),
+  EXPECT_EQ(static_cast<int>(DeviceStatusCollector::kMaxResourceUsageSamples),
             status_.cpu_utilization_pct().size());
   for (const auto utilization : status_.cpu_utilization_pct())
     EXPECT_EQ(idle_cpu_usage, utilization);

components/policy/proto/device_management_backend.proto

@@ -662,14 +662,17 @@ message DeviceStatusReportRequest {
   // List of visible/configured networks
   repeated NetworkState network_state = 11;
 
-  // Samples of CPU utilization (0-100), sampled once every 60 seconds.
+  // Samples of CPU utilization (0-100), sampled once every 120 seconds.
   repeated int32 cpu_utilization_pct = 12;
 
   // Free RAM (unreliable due to GC).
-  optional int64 system_ram_free = 13;
+  optional int64 deprecated_system_ram_free = 13 [deprecated = true];
 
   // Total RAM on the device.
   optional int64 system_ram_total = 14;
+
+  // Samples of free RAM [in bytes] (unreliable due to GC).
+  repeated int64 system_ram_free = 15;
 }
 
 // Provides status information for an installed app/extension.