Merge pull request #2234 from DataDog/simaoseica/RUM-8628/calculate-hang-rate-and-hitch-rate

RUM-8628: Calculate Hang rate and Hitch rate

Author: simaoseica-dd

DatadogCore/Tests/Datadog/Mocks/RUM/RUMFeatureMocks.swift

@@ -775,6 +775,7 @@ extension RUMScopeDependencies {
         sessionSampler: Sampler = .mockKeepAll(),
         trackBackgroundEvents: Bool = .mockAny(),
         trackFrustrations: Bool = true,
+        hasAppHangsEnabled: Bool = true,
         firstPartyHosts: FirstPartyHosts = .init([:]),
         eventBuilder: RUMEventBuilder = RUMEventBuilder(eventsMapper: .mockNoOp()),
         rumUUIDGenerator: RUMUUIDGenerator = DefaultRUMUUIDGenerator(),
@@ -805,6 +806,7 @@ extension RUMScopeDependencies {
             sessionSampler: sessionSampler,
             trackBackgroundEvents: trackBackgroundEvents,
             trackFrustrations: trackFrustrations,
+            hasAppHangsEnabled: hasAppHangsEnabled,
             firstPartyHosts: firstPartyHosts,
             eventBuilder: eventBuilder,
             rumUUIDGenerator: rumUUIDGenerator,
@@ -831,6 +833,7 @@ extension RUMScopeDependencies {
         sessionSampler: Sampler? = nil,
         trackBackgroundEvents: Bool? = nil,
         trackFrustrations: Bool? = nil,
+        hasAppHangsEnabled: Bool? = nil,
         firstPartyHosts: FirstPartyHosts? = nil,
         eventBuilder: RUMEventBuilder? = nil,
         rumUUIDGenerator: RUMUUIDGenerator? = nil,
@@ -855,6 +858,7 @@ extension RUMScopeDependencies {
             sessionSampler: sessionSampler ?? self.sessionSampler,
             trackBackgroundEvents: trackBackgroundEvents ?? self.trackBackgroundEvents,
             trackFrustrations: trackFrustrations ?? self.trackFrustrations,
+            hasAppHangsEnabled: hasAppHangsEnabled ?? self.hasAppHangsEnabled,
             firstPartyHosts: firstPartyHosts ?? self.firstPartyHosts,
             eventBuilder: eventBuilder ?? self.eventBuilder,
             rumUUIDGenerator: rumUUIDGenerator ?? self.rumUUIDGenerator,

DatadogRUM/Sources/Feature/RUMFeature.swift

@@ -74,6 +74,7 @@ internal final class RUMFeature: DatadogRemoteFeature {
             sessionSampler: Sampler(samplingRate: configuration.debugSDK ? 100 : configuration.sessionSampleRate),
             trackBackgroundEvents: configuration.trackBackgroundEvents,
             trackFrustrations: configuration.trackFrustrations,
+            hasAppHangsEnabled: configuration.appHangThreshold != nil,
             firstPartyHosts: {
                 switch configuration.urlSessionTracking?.firstPartyHostsTracing {
                 case let .trace(hosts, _, _):

DatadogRUM/Sources/RUMMonitor/Scopes/RUMScopeDependencies.swift

@@ -33,6 +33,7 @@ internal struct RUMScopeDependencies {
     let sessionSampler: Sampler
     let trackBackgroundEvents: Bool
     let trackFrustrations: Bool
+    let hasAppHangsEnabled: Bool
     let firstPartyHosts: FirstPartyHosts?
     let eventBuilder: RUMEventBuilder
     let rumUUIDGenerator: RUMUUIDGenerator
@@ -71,6 +72,7 @@ internal struct RUMScopeDependencies {
         sessionSampler: Sampler,
         trackBackgroundEvents: Bool,
         trackFrustrations: Bool,
+        hasAppHangsEnabled: Bool,
         firstPartyHosts: FirstPartyHosts?,
         eventBuilder: RUMEventBuilder,
         rumUUIDGenerator: RUMUUIDGenerator,
@@ -94,6 +96,7 @@ internal struct RUMScopeDependencies {
         self.sessionSampler = sessionSampler
         self.trackBackgroundEvents = trackBackgroundEvents
         self.trackFrustrations = trackFrustrations
+        self.hasAppHangsEnabled = hasAppHangsEnabled
         self.firstPartyHosts = firstPartyHosts
         self.eventBuilder = eventBuilder
         self.rumUUIDGenerator = rumUUIDGenerator

DatadogRUM/Sources/RUMMonitor/Scopes/RUMViewScope.swift

@@ -11,6 +11,7 @@ internal class RUMViewScope: RUMScope, RUMContextProvider {
     struct Constants {
         static let frozenFrameThresholdInNs = (0.7).toInt64Nanoseconds // 700ms
         static let slowRenderingThresholdFPS = 55.0
+        static let minimumTimeSpentForRates = 1.0 // 1s
         /// The pre-warming detection attribute key
         static let activePrewarm = "active_pre_warm"
     }
@@ -116,6 +117,8 @@ internal class RUMViewScope: RUMScope, RUMContextProvider {
     private let viewEndedMetric: ViewEndedMetricController
     /// Tracks "View Hitches" for this view.
     private let viewHitchesMetric: (ViewHitchesMetric & RenderLoopReader)?
+    /// Tracks "View Hangs" for this view.
+    private var totalAppHangDuration: Double = 0.0
 
     init(
         isInitialView: Bool,
@@ -546,6 +549,18 @@ internal class RUMViewScope: RUMScope, RUMContextProvider {
         let isSlowRendered = refreshRateInfo?.meanValue.map { $0 < Constants.slowRenderingThresholdFPS }
         let networkSettledTime = networkSettledMetric.value(with: context.applicationStateHistory)
         var interactionToNextViewTime = interactionToNextViewMetric?.value(for: viewUUID) ?? .failure(.disabled)
+        var slowFramesRate: Double?
+        var freezeRate: Double?
+        if let command = command as? RUMStopViewCommand,
+           command.identity == identity,
+           timeSpent >= Constants.minimumTimeSpentForRates {
+            if let totalHitchesDuration = viewHitchesMetric?.hitchesDataModel.hitchesDuration {
+                slowFramesRate = totalHitchesDuration / timeSpent * Double(1.toMilliseconds) // milliseconds/second
+            }
+            if dependencies.hasAppHangsEnabled {
+                freezeRate = totalAppHangDuration / timeSpent * 1.hours // seconds/hour
+            }
+        }
         // Only overwrite with a custom value if INV was disabled
         if interactionToNextViewTime == .failure(.disabled),
            let customInvValue = internalAttributes[CrossPlatformAttributes.customINVValue] as? (any BinaryInteger),
@@ -636,7 +651,7 @@ internal class RUMViewScope: RUMScope, RUMContextProvider {
                 firstInputTime: nil,
                 flutterBuildTime: viewPerformanceMetrics[.flutterBuildTime]?.asFlutterBuildTime(),
                 flutterRasterTime: viewPerformanceMetrics[.flutterRasterTime]?.asFlutterRasterTime(),
-                freezeRate: nil,
+                freezeRate: freezeRate,
                 frozenFrame: .init(count: frozenFramesCount),
                 frustration: .init(count: frustrationCount),
                 id: viewUUID.toRUMDataFormat,
@@ -664,7 +679,7 @@ internal class RUMViewScope: RUMScope, RUMContextProvider {
                 refreshRateMin: refreshRateInfo?.minValue,
                 resource: .init(count: resourcesCount.toInt64),
                 slowFrames: viewHitchesMetric?.hitchesDataModel.hitches.map { .init(duration: $0.duration, start: $0.start) },
-                slowFramesRate: nil,
+                slowFramesRate: slowFramesRate,
                 timeSpent: timeSpent.toInt64Nanoseconds,
                 url: viewPath
             )
@@ -703,6 +718,7 @@ internal class RUMViewScope: RUMScope, RUMContextProvider {
 
     private func sendErrorEvent(on command: RUMErrorCommand, context: DatadogContext, writer: Writer) {
         errorsCount += 1
+        totalAppHangDuration += (command as? RUMAddCurrentViewAppHangCommand)?.hangDuration ?? 0
 
         var commandAttributes = command.globalAttributes.merging(command.attributes) { $1 }
         let errorFingerprint: String? = commandAttributes.removeValue(forKey: RUM.Attributes.errorFingerprint)?.dd.decode()

DatadogRUM/Sources/RUMVitals/RenderLoop/ViewHitchesReader.swift

@@ -15,7 +15,7 @@ internal typealias Hitch = (start: Int64, duration: Int64)
 /**
  - parameters:
    - hitches: Array of view hitches (slow frames)
-   - hitchesDuration: Cumulative duration in ms of the view hitches
+   - hitchesDuration: Cumulative duration in seconds of the view hitches
  */
 internal typealias HitchesDataModel = (hitches: [Hitch], hitchesDuration: Double)
 
@@ -42,8 +42,8 @@ internal final class ViewHitchesReader: ViewHitchesMetric {
     private var startTimestamp: Double = 0
     private var nextFrameTimestamp: Double?
 
-    private var hangThreshold: TimeInterval
-    private var acceptableLatency: TimeInterval
+    private let hangThreshold: TimeInterval
+    private let acceptableLatency: TimeInterval
 
     /// Amount of time when the frames are rendered too late.
     private var _hitchesDuration: Double = 0.0

DatadogRUM/Tests/Mocks/RUMFeatureMocks.swift

@@ -795,14 +795,15 @@ extension RUMScopeDependencies {
         sessionSampler: Sampler = .mockKeepAll(),
         trackBackgroundEvents: Bool = .mockAny(),
         trackFrustrations: Bool = true,
+        hasAppHangsEnabled: Bool = true,
         firstPartyHosts: FirstPartyHosts = .init([:]),
         eventBuilder: RUMEventBuilder = RUMEventBuilder(eventsMapper: .mockNoOp()),
         rumUUIDGenerator: RUMUUIDGenerator = DefaultRUMUUIDGenerator(),
         backtraceReporter: BacktraceReporting = BacktraceReporterMock(backtrace: nil),
         ciTest: RUMCITest? = nil,
         syntheticsTest: RUMSyntheticsTest? = nil,
         renderLoopObserver: RenderLoopObserver? = nil,
-        viewHitchesMetricFactory: @escaping () -> RenderLoopReader & ViewHitchesMetric = { ViewHitchesMock.mockAny() },
+        viewHitchesMetricFactory: @escaping () -> (RenderLoopReader & ViewHitchesMetric)? = { ViewHitchesMock.mockAny() },
         vitalsReaders: VitalsReaders? = nil,
         onSessionStart: @escaping RUM.SessionListener = mockNoOpSessionListener(),
         viewCache: ViewCache = ViewCache(dateProvider: SystemDateProvider()),
@@ -821,6 +822,7 @@ extension RUMScopeDependencies {
             sessionSampler: sessionSampler,
             trackBackgroundEvents: trackBackgroundEvents,
             trackFrustrations: trackFrustrations,
+            hasAppHangsEnabled: hasAppHangsEnabled,
             firstPartyHosts: firstPartyHosts,
             eventBuilder: eventBuilder,
             rumUUIDGenerator: rumUUIDGenerator,
@@ -847,6 +849,7 @@ extension RUMScopeDependencies {
         sessionSampler: Sampler? = nil,
         trackBackgroundEvents: Bool? = nil,
         trackFrustrations: Bool? = nil,
+        hasAppHangsEnabled: Bool? = nil,
         firstPartyHosts: FirstPartyHosts? = nil,
         eventBuilder: RUMEventBuilder? = nil,
         rumUUIDGenerator: RUMUUIDGenerator? = nil,
@@ -871,6 +874,7 @@ extension RUMScopeDependencies {
             sessionSampler: sessionSampler ?? self.sessionSampler,
             trackBackgroundEvents: trackBackgroundEvents ?? self.trackBackgroundEvents,
             trackFrustrations: trackFrustrations ?? self.trackFrustrations,
+            hasAppHangsEnabled: hasAppHangsEnabled ?? self.hasAppHangsEnabled,
             firstPartyHosts: firstPartyHosts ?? self.firstPartyHosts,
             eventBuilder: eventBuilder ?? self.eventBuilder,
             rumUUIDGenerator: rumUUIDGenerator ?? self.rumUUIDGenerator,