tools/metrics/histograms/metadata/compositing/histograms.xml - chromium/src - Git at Google

 <!--
 Copyright 2020 The Chromium Authors
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 found in the LICENSE file.
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 <!--
 This file is used to generate a comprehensive list of Compositing histograms
 along with a detailed description for each histogram.

 For best practices on writing histogram descriptions, see
 https://chromium.googlesource.com/chromium/src.git/+/HEAD/tools/metrics/histograms/README.md

 Please follow the instructions in the OWNERS file in this directory to find a
 reviewer. If no OWNERS file exists, please consider signing up at
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 <histogram-configuration>

 <histograms>

 <variants name="LCDTextDisallowedReasonDPI">
   <variant name="HighDPI"
       summary="In web pages where device scale factor is greater than or
                equal to 1.5."/>
   <variant name="LowDPI"
       summary="In web pages where device scale factor is less than 1.5."/>
 </variants>

 <variants name="SmoothnessSequence">
   <variant name="AllAnimations"
       summary="its animations (e.g. comositor-driven animations, main-thread
                driven animations, and raf-driven animations, etc.)"/>
   <variant name="AllInteractions"
       summary="its supported combinations of interaction types (e.g.
                scrolling, pinching, etc.) and input device types (e.g.
                touchscreen, touchpad, mousewheel, etc.)"/>
   <variant name="CanvasAnimation" summary="canvas animations"/>
   <variant name="CompositorAnimation"
       summary="compositor thread driven animations"/>
   <variant name="JSAnimation" summary="JS driven animations"/>
   <variant name="MainThreadAnimation" summary="main thread driven animations"/>
   <variant name="PinchZoom" summary="pinch to zoom interctions"/>
   <variant name="RAF" summary="raf driven animations"/>
   <variant name="ScrollbarScroll" summary="scrollbar scrolling"/>
   <variant name="SETCompositorAnimation"
       summary="compositor animations during a view transition"/>
   <variant name="SETMainThreadAnimation"
       summary="main thread animations during a view transition"/>
   <variant name="TouchScroll" summary="touch scrolling"/>
   <variant name="Video" summary="video playback"/>
   <variant name="WheelScroll" summary="wheel scrolling"/>
 </variants>

 <variants name="SmoothnessThread">
   <variant name=""/>
   <variant name="CompositorThread."/>
   <variant name="MainThread."/>
 </variants>

 <histogram name="Compositing.Browser.LayersUpdateTime" units="microseconds"
     expires_after="2024-06-30">
   <owner>pdr@chromium.org</owner>
   <owner>animations-dev@chromium.org</owner>
   <summary>
     Time spent updating layers, in microseconds. Recorded when layers are
     updated (in a browser process).

     Warning: This metric may include reports from clients with low-resolution
     clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports
     will cause this metric to have an abnormal distribution. When considering
     revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the
     solution.
   </summary>
 </histogram>

 <histogram name="Compositing.Browser.LayerTreeImpl.CalculateDrawPropertiesUs"
     units="microseconds" expires_after="2023-03-19">
   <owner>pdr@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <summary>
     Time spent updating layer draw properties, in microseconds. Recorded when a
     LayerTreeImpl's draw properties are updated (in a browser process).

     Warning: This metric may include reports from clients with low-resolution
     clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports
     will cause this metric to have an abnormal distribution. When considering
     revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the
     solution.
   </summary>
 </histogram>

 <histogram name="Compositing.BufferQueue.TimeUntilBuffersRecreatedMs"
     units="ms" expires_after="2024-06-16">
   <owner>khaslett@chromium.org</owner>
   <owner>petermcneeley@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     The time since a BufferQueue's buffers were destroyed until they were
     recreated. If this time is commonly very small, that is a problem. Recorded
     when the buffer recreates buffers that were previously destroyed. For a
     single BufferQueue this should be once per frame at worst.
   </summary>
 </histogram>

 <histogram name="Compositing.ColorGamut" enum="ColorGamut"
     expires_after="2024-04-16">
   <owner>vasilyt@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Every time a frame is presented, record the generalized color gamut of that
     frame. Note: this metric was expired from 2022-02-06 to 2023-11-17.
   </summary>
 </histogram>

 <histogram name="Compositing.DecodeLCPCandidateImage.{DecodeMethod}"
     enum="Boolean" expires_after="2024-12-01">
   <owner>mmocny@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <summary>
     Reports whether an image decode was for an image that might be used as the
     Largest Contentful Image, and then whether a missing tile at raster time
     includes such an image. The goal is to get an approximate idea of how many
     LCP candidate images miss their frame deadline, and hence how often we may
     report LCP too soon.

     Recorded on every {DecodeMethod}

     Note: this metric was expired from 2023-01-31 to 2023-12-20.
   </summary>
   <token key="DecodeMethod">
     <variant name="Hardware" summary="hardware image decode task completion."/>
     <variant name="MissedDeadline"
         summary="call to PrepareTiles() in which there was a missing tile.
                  True if any missing tile contains an LCP candidate decode
                  that has not completed."/>
     <variant name="Software" summary="software image decode task completion."/>
   </token>
 </histogram>

 <histogram name="Compositing.DidMainThreadBlockDuringCommit" enum="Boolean"
     expires_after="2024-06-30">
   <owner>szager@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <owner>sky@chromium.org</owner>
   <summary>
     Recorded on every commit. Indicates whether the renderer's main thread was
     blocked waiting for the impl thread to commit. True indicates the main
     thread did block.
   </summary>
 </histogram>

 <histogram name="Compositing.DirectRenderer.OverlayProcessingUs"
     units="microseconds" expires_after="2024-06-30">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     Time spent processing quads to see which can be replaced with overlays. This
     is logged once per frame, when a frame should be drawn. Only reported for
     platforms supporting high resolution clocks.
   </summary>
 </histogram>

 <histogram name="Compositing.DirectRenderer.PartialSwap.ExtraDamage" units="%"
     expires_after="2024-03-16">
   <owner>vasilyt@chromium.org</owner>
   <owner>petermcneeley@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     The area of the display damage that was added to current frame damage after
     all adjustments, including FrameBufferDamage from buffer queue and render
     pass filters.

     This metric is reported once per frame only on platforms/devices that
     support partial swap and does not include &quot;empty swap&quot; (no frame
     damage) case

     Note: this metric was expired from 2022-10-16 to 2023-06-09.
   </summary>
 </histogram>

 <histogram name="Compositing.DirectRenderer.PartialSwap.FrameBufferDamage"
     units="%" expires_after="2024-03-16">
   <owner>vasilyt@chromium.org</owner>
   <owner>petermcneeley@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     The area of the display that was damaged since previous draw to this frame
     buffer.

     This metric is reported once per frame only on platforms/devices that
     support partial swap and does not include &quot;empty swap&quot; (no frame
     damage) case.

     Note: this metric was expired from 2022-10-23 to 2023-06-09.
   </summary>
 </histogram>

 <histogram name="Compositing.DirectRenderer.PartialSwap.RootDamage" units="%"
     expires_after="2024-07-21">
   <owner>vasilyt@chromium.org</owner>
   <owner>petermcneeley@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     The area of the display that was damaged in current frame.

     This metric is reported only on platforms/devices that support partial swap
     and does not include &quot;empty swap&quot; (no frame damage) case.
   </summary>
 </histogram>

 <histogram name="Compositing.DirectRenderer.PartialSwap.TotalDamage" units="%"
     expires_after="2024-05-19">
   <owner>vasilyt@chromium.org</owner>
   <owner>petermcneeley@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     The total area of the display that will be redrawn this frame.

     This metric is reported only on platforms/devices that support partial swap
     and does not include &quot;empty swap&quot; (no frame damage) case

     Note: this metric was expired from 2023-04-30 to 2023-06-09.
   </summary>
 </histogram>

 <histogram name="Compositing.DirectRenderer.SkipAllNonRootRenderPassesPerFrame"
     enum="BooleanSkipped" expires_after="2024-06-30">
   <owner>magchen@chromium.org</owner>
   <owner>ccameron@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Whether all non-root render passes in a frame are skipped. Logged once per
     frame during DrawFrame for the frames with non-root render passes.
   </summary>
 </histogram>

 <histogram name="Compositing.DirectRenderer.SkipNonRootRenderPass"
     enum="BooleanSkipped" expires_after="2024-06-30">
   <owner>magchen@chromium.org</owner>
   <owner>ccameron@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Logged for every non-root render pass in DrawRenderPass during DrawFrame.
     True if there is no damages to the render pass and the rendering is skipped.
   </summary>
 </histogram>

 <histogram name="Compositing.DirectRenderer.SkippedNonRootRenderPassOutputSize"
     units="pixels" expires_after="2024-06-30">
   <owner>magchen@chromium.org</owner>
   <owner>ccameron@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Pixel size for a skipped nonroot render pass output surface. Recorded in Viz
     DirectRenderer draw frame.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.AdpfHintUs" units="microseconds"
     expires_after="2024-06-30">
   <owner>boliu@chromium.org</owner>
   <owner>vasilyt@chromium.org</owner>
   <summary>
     This is logged once for every ADPF performance hint report, which is
     generally once every frame on Android device that supports ADPF and ADPF is
     enabled. It's the interval reported to ADPF, which is currently implemented
     as the wall clock time from vsync frame time to swap_start. Only reported
     for platforms supporting high resolution clocks.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.Draw.Occlusion.Calculation.Time"
     units="microseconds" expires_after="2024-06-30">
   <owner>yiyix@chromium.org</owner>
   <owner>chromeos-gfx@chromium.org</owner>
   <summary>
     Time spent to remove invisible quads from the quad_list in CompositorFrame.

     Warning: This metric may include reports from clients with low-resolution
     clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports
     will cause this metric to have an abnormal distribution. When considering
     revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the
     solution.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.DrawToSwapUs" units="microseconds"
     expires_after="2024-06-30">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     This is logged once per frame, if the output surface provides timing
     information. It measures the time from the display compositor starting a
     draw on the Viz Compositor thread to issuing all related draw calls to the
     driver on the Gpu Main thread. Only reported for platforms supporting high
     resolution clocks.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.DrmOverlayManager.FirstTestPageFlipPassed"
     enum="Boolean" expires_after="2023-08-20">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     Logged zero or more times per frame, whether the first call to
     HardwareDisplayController.TestPageFlip succeeded.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.DrmOverlayManager.TestPageFlipCount"
     units="units" expires_after="2024-06-30">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     Logged zero or more times per frame, the number of times TestPageFlip is
     called on the HardwareDisplayController.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.DrmOverlayManager.TestPageFlipUs"
     units="microseconds" expires_after="2024-06-30">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     Logged zero or more times per frame, the duration of calling TestPageFlip on
     the HardwareDisplayController. Only reported for platforms supporting high
     resolution clocks.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.DrmThread.CheckOverlayCapabilitiesSyncUs"
     units="microseconds" expires_after="2023-06-18">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     Logged zero or more times per frame, the duration of
     DrmThread::CheckOverlayCapabilitiesSync(). This is the total time spent on
     the DRM thread to check a set of overlay candidates. Only reported for
     platforms supporting high resolution clocks.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.FlattenedRenderPassCount" units="units"
     expires_after="2024-06-30">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     This is logged once per frame. It is the number of renderer passes after
     flattening all possible render passes. If the value is more than one, then
     an intermediate rendering target must be used during the rendering of the
     frame for each render pass greater than one.
   </summary>
 </histogram>

 <histogram
     name="Compositing.Display.HardwareDisplayController.SchedulePageFlipResult"
     enum="PageFlipResult" expires_after="2024-03-02">
   <owner>seanpaul@chromium.org</owner>
   <owner>chromeos-gfx-compositor@chromium.org</owner>
   <summary>
     Logged once per frame, represents whether we could successfully schedule a
     page flip, or what error we encountered along the way. Note: this metric was
     expired from 2023-03-02 to 2023-04-13.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.OverlayCombinationCache.NumIdsEvicted"
     units="units" expires_after="2023-06-04">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     Logged zero or one times per frame, the number of stale candidate ids we are
     evicting from the OverlayCombinationCache this frame. If this number is high
     the CandidateIds or the candidates proposed are likely less stable than they
     should be.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.OverlayProcessorOzone.MaxPlanesSupported"
     units="units" expires_after="2023-08-20">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     This is logged every time a valid HardwareCapabilities is received from DRM
     when display configuration may have changed. It records the number of
     overlay planes we have available on this device including the primary plane.
   </summary>
 </histogram>

 <histogram
     name="Compositing.Display.OverlayProcessorUsingStrategy.CandidateCombinationPreviouslySucceeded"
     enum="Boolean" expires_after="2023-08-20">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     Logged zero or one times per frame, whether or not the candidate combination
     being tested this frame was successfully promoted to overlays on the
     previous frame.
   </summary>
 </histogram>

 <histogram
     name="Compositing.Display.OverlayProcessorUsingStrategy.CheckOverlaySupportCallCount"
     units="units" expires_after="2024-06-30">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     This is logged once per frame, the number of times CheckOverlaySupport is
     called this frame.
   </summary>
 </histogram>

 <histogram
     name="Compositing.Display.OverlayProcessorUsingStrategy.CheckOverlaySupportUs"
     units="microseconds" expires_after="2024-06-30">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     Logged zero or more times per frame, the time spent checking if a set of
     candidates can be promoted to overlay. Only reported for platforms
     supporting high resolution clocks.
   </summary>
 </histogram>

 <histogram
     name="Compositing.Display.OverlayProcessorUsingStrategy.FramesAttemptingRequiredOverlays"
     enum="Boolean" expires_after="2024-05-26">
   <owner>zoraiznaeem@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Records once per frame, whether we will attempt to promote any required
     overlay or not in that frame.
   </summary>
 </histogram>

 <histogram
     name="Compositing.Display.OverlayProcessorUsingStrategy.FramesScalingRequiredOverlays"
     enum="Boolean" expires_after="2024-06-30">
   <owner>zoraiznaeem@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Records zero or once per frame, whether we attempted scaling any required
     overlay.
   </summary>
 </histogram>

 <histogram
     name="Compositing.Display.OverlayProcessorUsingStrategy.NumOverlays{Counted}"
     units="overlay candidates" expires_after="2024-06-30">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <owner>chromeos-gfx-compositor@chromium.org</owner>
   <summary>
     Logged once per frame, the number of overlays {Counted}. Note: this metric
     was expired from 2022-11-30 to 2023-04-13.
   </summary>
   <token key="Counted">
     <variant name="Attempted"
         summary="attempted. This is only logged when using the
                  AttemptMultipleOverlays path."/>
     <variant name="Failed"
         summary="failed. This is only logged when using the
                  AttemptMultipleOverlays path."/>
     <variant name="Promoted" summary="promoted."/>
   </token>
 </histogram>

 <histogram
     name="Compositing.Display.OverlayProcessorUsingStrategy.NumQuadsConsidered"
     units="units" expires_after="2023-06-18">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     Logged once per frame, the number of quads considered for promotion to
     overlay.
   </summary>
 </histogram>

 <histogram
     name="Compositing.Display.OverlayProcessorUsingStrategy.ShouldAttemptMultipleOverlays"
     enum="AttemptingMultipleOverlays" expires_after="2024-02-25">
   <owner>khaslett@chromium.org</owner>
   <owner>kylechar@chromium.org</owner>
   <summary>
     Logged zero or one times per frame, whether we're using the
     AttemptingMultipleOverlays codepath this frame or why we arent.
   </summary>
 </histogram>

 <histogram
     name="Compositing.Display.OverlayProcessorUsingStrategy.WorkingScaleFactorForRequiredOverlays"
     units="scale_factor" expires_after="2024-06-30">
   <owner>zoraiznaeem@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Records the scale factor that is used to downscale successfully promoted
     required candidates. It is only logged once per frame if a required overlay
     is promoted. Note: The scale factor value is logged as `scale_factor * 100`.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.PendingSwaps" units="swaps"
     expires_after="2024-06-16">
   <owner>sashamcintosh@chromium.org</owner>
   <owner>chromeos-gfx@chromium.org</owner>
   <summary>
     Records the count of pending swaps in the display scheduler. Length of the
     swap chain can be used as a rough approximation for input latency. Recorded
     before the swap executes. Refer to Display::DrawAndSwap for details.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.VizDependencyResolvedToGpuStartedDrawUs"
     units="microseconds" expires_after="2024-06-16">
   <owner>vasilyt@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     This is logged once per frame, if the output surface provides timing
     information. It measures delta between the time when display compositor draw
     task's dependencies have been solved and the time when the Gpu Thread
     started processing it. Only reported for platforms supporting high
     resolution clocks. Note: this metric was expired from 2022-12-18 to
     2023-11-17.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.VizScheduledDrawToDependencyResolvedUs"
     units="microseconds" expires_after="2024-06-16">
   <owner>vasilyt@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     This is logged once per frame if the output surface provides timing
     information. It measures delta between the time when display compositor
     scheduled first draw task for the current frame on Viz Compositor thread and
     the time when the task's dependencies have been resolved and the task is
     ready for the Gpu Thread to start processing it. Recorded when swap
     completes. Only reported for platforms supporting high resolution clocks.
     Note: this metric was expired from 2023-08-27 to 2023-11-17.
   </summary>
 </histogram>

 <histogram name="Compositing.Display.VizScheduledDrawToGpuStartedDrawUs"
     units="microseconds" expires_after="2024-06-16">
   <owner>vasilyt@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     This is logged once per frame if the output surface provides timing
     information. It measures delta between the time when display compositor
     scheduled first draw task for the current frame on Viz Compositor thread and
     the time when Gpu Thread started processing it. Recorded when swap
     completes. Only reported for platforms supporting high resolution clocks.
     Note: this metric was expired from 2022-12-18 to 2023-11-17.
   </summary>
 </histogram>

 <histogram name="Compositing.FrameRateDecider.ToggleFrameRateCase"
     enum="ToggleFrameRateCase" expires_after="2024-03-30">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     The count of cases to decide whether we should toggle framerate or not in
     FrameRateDecider. This is logged at 1/1000 probability of frames with
     video(s) on screen. This aims to determine how frequently Chormium is
     rendering single video with perfect cadence to the supported frame rates.
   </summary>
 </histogram>

 <histogram name="Compositing.MainThreadBlockedDuringCommitTime"
     units="microseconds" expires_after="2024-06-30">
   <owner>szager@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <owner>sky@chromium.org</owner>
   <summary>
     The time that the renderer's main thread blocked waiting for the impl thread
     to commit. This is only reported if the main thread blocked.

     Drops reports on clients with low-resolution clocks, biasing to a portion of
     the population on Windows. See Windows.HasHighResolutionTimeTicks for the
     affected sample.
   </summary>
 </histogram>

 <histogram
     name="Compositing.MainThreadBlockedDuringCommitTime.ApplyCompositorChanges"
     units="microseconds" expires_after="2023-10-08">
   <owner>szager@chromium.org</owner>
   <owner>pdr@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <summary>
     The time that ApplyCompositorChanges is blocked waiting for the impl thread
     to commit. This is a subset of the total time spent in
     Compositing.MainThreadBlockedDuringCommitTime.

     Drops reports on clients with low-resolution clocks, biasing to a portion of
     the population on Windows. See Windows.HasHighResolutionTimeTicks for the
     affected sample.
   </summary>
 </histogram>

 <histogram name="Compositing.Renderer.AnimationUpdateOnMissingPropertyNode"
     enum="Boolean" expires_after="2024-12-02">
   <owner>awogbemila@chromium.org</owner>
   <owner>input-dev@chromium.org</owner>
   <summary>
     Records when we attempt to update an animation with a missing property node.
     See crbug.com/1307498. We safely handle this case but until we find and fix
     the root cause, this histogram allows us to keep track of the frequency at
     this occurs.
   </summary>
 </histogram>

 <histogram name="Compositing.Renderer.CALayerResult" enum="CALayerResult"
     expires_after="2024-06-30">
   <owner>ccameron@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     The outcome of attempting to replace all renderer tiles with CALayers.
     Either success, or the first reason why a DrawQuad couldn't be replaced by a
     CALayer.
   </summary>
 </histogram>

 <histogram name="Compositing.Renderer.LayersUpdateTime" units="microseconds"
     expires_after="2024-06-30">
   <owner>pdr@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <summary>
     Time spent updating layers, in microseconds. Recorded when layers are
     updated (in a renderer process).

     Warning: This metric may include reports from clients with low-resolution
     clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports
     will cause this metric to have an abnormal distribution. When considering
     revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the
     solution.
   </summary>
 </histogram>

 <histogram name="Compositing.Renderer.LCDTextDisallowedReasonKPixels2.{DPI}"
     enum="LCDTextDisallowedReason" expires_after="2024-06-30">
   <owner>wangxianzhu@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <summary>
     Records the approximate kilo-pixels covered by text drawing operations by
     LCD-text disallowed reasons. Hence the histogram value for each reason is
     the approximate number of non-LCD kilo-pixels resulting from that reason.
     Recorded when the renderer is idle, at minimum interval of the longer of 1
     minute and 500 begin frames for each local frame tree.
   </summary>
   <token key="DPI" variants="LCDTextDisallowedReasonDPI"/>
 </histogram>

 <histogram name="Compositing.Renderer.LCDTextDisallowedReasonLayers2.{DPI}"
     enum="LCDTextDisallowedReason" expires_after="2024-06-30">
   <owner>wangxianzhu@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <summary>
     Records the number of layers containing text by LCD-text disallowed reasons.
     Recorded along with Compositing.Renderer.LCDTextDisallowedReasonKPixels.
   </summary>
   <token key="DPI" variants="LCDTextDisallowedReasonDPI"/>
 </histogram>

 <histogram name="Compositing.Renderer.NumActiveLayers" units="layers"
     expires_after="2024-07-21">
   <owner>pdr@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <summary>
     The number of layers in the active tree for each compositor frame. This is
     logged once per frame, before the frame is drawn (in a renderer process).
   </summary>
 </histogram>

 <histogram name="Compositing.Renderer.NumActivePictureLayers" units="layers"
     expires_after="2024-07-21">
   <owner>pdr@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <summary>
     The number of PictureLayers in the active tree for each compositor frame.
     This is logged once per frame, before the frame is drawn (in a renderer
     process).
   </summary>
 </histogram>

 <histogram name="Compositing.Renderer.NumRenderSurfaces" units="surfaces"
     expires_after="2024-07-21">
   <owner>pdr@chromium.org</owner>
   <owner>paint-dev@chromium.org</owner>
   <summary>
     The number of render surfaces in the render surface layer list. Recorded
     each time the render surface layer list is constructed (in a renderer
     process).
   </summary>
 </histogram>

 <histogram name="Compositing.SkiaRenderer.DirectlyDrawableRenderPassWithRPDQ"
     enum="Boolean" expires_after="2024-06-30">
   <owner>khushalsagar@chromium.org</owner>
   <owner>vmpstr@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Logged for every nested RenderPass to indicate whether it could have been
     drawn directly because it has a single RPDQ and no other effect which would
     require producing a render pass.
   </summary>
 </histogram>

 <histogram name="Compositing.SkiaRenderer.DrawTileDrawQuad.UsingRawDraw"
     enum="Boolean" expires_after="2023-06-11">
   <owner>penghuang@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>Records if the TileDrawQuad is rendered with RawDraw.</summary>
 </histogram>

 <histogram name="Compositing.SkiaRenderer.SkipOverlayRenderPassDrawQuad"
     enum="BooleanSkipped" expires_after="2024-06-30">
   <owner>magchen@chromium.org</owner>
   <owner>ccameron@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Logged for every RenderPassDrawQuad in the overlay list during
     ScheduleOverlays. An Overlay RenderPassDrawQuad is skipped if there is no
     damages to the render pass and the RenderPassDrawQuad settings are the same.
   </summary>
 </histogram>

 <histogram name="Compositing.SkiaRenderer.SkippedOverlayRenderPassDrawQuadSize"
     units="pixels" expires_after="2024-06-30">
   <owner>magchen@chromium.org</owner>
   <owner>ccameron@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Pixel size for a skipped overlay render pass draw quad. Recorded in
     SkiaRenderer ScheduleOverlays.
   </summary>
 </histogram>

 <histogram name="Compositing.SkiaRenderer.VertexOpacityUsage"
     units="VertexOpacityUsage" expires_after="2024-06-28">
   <owner>petermcneeley@chromium.org</owner>
   <owner>kyle@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Vertex usage is logged cumulatively for every 1000 TextureDrawQuads drawn.
   </summary>
 </histogram>

 <histogram name="Compositing.SurfaceAggregator.AggregateUs"
     units="microseconds" expires_after="2024-06-30">
   <owner>kylechar@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Time spent aggregating compositor frames from different surfaces in
     microseconds. This is logged once per frame.

     Warning: This metric may include reports from clients with low-resolution
     clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports
     will cause this metric to have an abnormal distribution. When considering
     revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the
     solution.
   </summary>
 </histogram>

 <histogram name="Compositing.SurfaceAggregator.CopiedSurfaceCount"
     units="surfaces" expires_after="2024-06-30">
   <owner>kylechar@chromium.org</owner>
   <owner>jonross@chromium.org</owner>
   <summary>
     The number of surfaces where the active CompositorFrame was copied into the
     AggregateFrame during surface aggregation. This is logged once per frame.
   </summary>
 </histogram>

 <histogram name="Compositing.SurfaceAggregator.CopyUs" units="microseconds"
     expires_after="2024-06-30">
   <owner>kylechar@chromium.org</owner>
   <owner>jonross@chromium.org</owner>
   <summary>
     Time spent copying quads during surface aggregation. This is a subset of the
     time recorded for Compositing.SurfaceAggregator.AggregateUs and is logged
     once per frame.

     Warning: This metric does not include reports from clients with
     low-resolution clocks.
   </summary>
 </histogram>

 <histogram name="Compositing.SurfaceAggregator.DeclareResourcesUs"
     units="microseconds" expires_after="2024-02-01">
   <owner>kylechar@chromium.org</owner>
   <owner>jonross@chromium.org</owner>
   <summary>
     Time spent declaring resources as used during surface aggregation. This is a
     subset of the time recorded for Compositing.SurfaceAggregator.AggregateUs
     and is logged once per frame.

     Warning: This metric does not include reports from clients with
     low-resolution clocks.
   </summary>
 </histogram>

 <histogram name="Compositing.SurfaceAggregator.Has{Type}PerFrame"
     enum="Boolean" expires_after="2024-06-30">
   <owner>magchen@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Record whether a frame has a specific type of render pass. This is logged
     once per frame.
   </summary>
   <token key="Type">
     <variant name="CopyRequests"/>
     <variant name="PixelMovingBackdropFilters"/>
     <variant name="PixelMovingFilters"/>
     <variant name="UnembeddedRenderPasses"/>
   </token>
 </histogram>

 <histogram name="Compositing.SurfaceAggregator.OrphanedRenderPassCount"
     units="render passes" expires_after="2024-07-14">
   <owner>kylechar@chromium.org</owner>
   <owner>khaslett@chromium.org</owner>
   <summary>
     The number of render passes that are drawn but are not contributing pixels
     to either the framebuffer or a CopyOutputRequest. These render passes can
     likely be skipped. This is logged once per frame.
   </summary>
 </histogram>

 <histogram name="Compositing.SurfaceAggregator.PrewalkedSurfaceCount"
     units="surfaces" expires_after="2024-06-30">
   <owner>kylechar@chromium.org</owner>
   <owner>jonross@chromium.org</owner>
   <summary>
     The number of surfaces that were looked at during the prewalk phase of
     surface aggregation. This is logged once per frame.
   </summary>
 </histogram>

 <histogram name="Compositing.SurfaceAggregator.PrewalkUs" units="microseconds"
     expires_after="2024-07-07">
   <owner>kylechar@chromium.org</owner>
   <owner>jonross@chromium.org</owner>
   <summary>
     Time spent doing prewalk during surface aggregation. This is a subset of the
     time recorded for Compositing.SurfaceAggregator.AggregateUs and is logged
     once per frame.

     Warning: This metric does not include reports from clients with
     low-resolution clocks.
   </summary>
 </histogram>

 <histogram name="Compositing.SurfaceManager.MarkForDestructionToDestroy"
     units="ms" expires_after="2024-10-20">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     The time between when a Surface has been Marked for Destruction, to when it
     is actually Destroyed.

     This time denotes how long the Surface remains referenced by other Surfaces,
     preventing deletion. This does not include the following time until the
     associated resources are released, and their memory is freed. This is logged
     once per destroyed Surface.
   </summary>
 </histogram>

 <histogram name="Compositing.TileManager.EnoughMemory" enum="Boolean"
     expires_after="2024-06-30">
   <owner>lizeb@chromium.org</owner>
   <owner>chrome-gpu-memory@google.com</owner>
   <summary>
     When memory is assigned to tiles, whether there was enough memory for all
     required tiles.
   </summary>
 </histogram>

 <histogram name="Compositing.TileManager.LimitWhenNotEnoughMemory" units="MB"
     expires_after="2024-06-30">
   <owner>lizeb@chromium.org</owner>
   <owner>chrome-gpu-memory@google.com</owner>
   <summary>
     When memory is assigned to tiles and there is not enough memory, the memory
     limit that the tile assignment was breaching..
   </summary>
 </histogram>

 <histogram
     name="CompositorLatency.CompositorOnlyFrame{InteractionType}.{StageType}"
     units="microseconds" expires_after="2024-07-07">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the duration of various stages in the pipeline as a single frame goes
     through the various stages in the compositor in the cases that there is no
     damage from main thread.

     This metric uses base::Histogram::FactoryMicrosecondsTimeGet so only users
     with high resolution clocks will report this metric.

     Note: This metric was expired from 2023-03-01 to 2023-05-05.
   </summary>
   <token key="InteractionType">
     <variant name=""/>
     <variant name=".CanvasAnimation"/>
     <variant name=".CompositorAnimation"/>
     <variant name=".JSAnimation"/>
     <variant name=".MainThreadAnimation"/>
     <variant name=".PinchZoom"/>
     <variant name=".RAF"/>
     <variant name=".ScrollbarScroll"/>
     <variant name=".SETCompositorAnimation"/>
     <variant name=".SETMainThreadAnimation"/>
     <variant name=".TouchScroll"/>
     <variant name=".WheelScroll"/>
   </token>
   <token key="StageType">
     <variant name="BeginImplFrameToFinishImpl"/>
     <variant name="ImplFrameDoneToSubmitCompositorFrame"/>
     <variant name="SendBeginMainFrameToBeginMainAbort"/>
     <variant name="SubmitCompositorFrameToPresentationCompositorFrame"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.BufferAvailableToBufferReady"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.BufferReadyToLatch"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.LatchToSwapEnd"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.ReceivedCompositorFrameToStartDraw"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.StartDrawToSwapStart"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.SubmitToReceiveCompositorFrame"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.SwapEndToPresentationCompositorFrame"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.SwapStartToBufferAvailable"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.SwapStartToSwapEnd"/>
     <variant name="TotalLatency"/>
   </token>
 </histogram>

 <histogram name="CompositorLatency.IpcThread.{LatencyType}"
     units="microseconds" expires_after="2024-06-12">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Reports the overhead of IPC's and thread hops during the production of a
     single frame. Measures {LatencyType}

     This is reported by the Renderer, at a subsampled rate of effectively once
     per 1000 frames. Non-Renderer clients do not report this. This metric drops
     reports on low-resolution clocks, which will bias the Windows population.
   </summary>
   <token key="LatencyType">
     <variant name="BeginMainFrameQueuing"
         summary="the time from when the Compositor thread posts
                  BeginMainFrame to when the task actually begins on the Main
                  thread. This is a subset of
                  CompositorLatency.*.SendBeginMainFrameToCommit."/>
     <variant name="DispatchToRenderer"
         summary="the time from when Viz dispatched the BeginFrameArgs to when
                  it is received by the client."/>
     <variant name="FrameTimeToDispatch"
         summary="the time from the targeted frame start time to when Viz
                  dispatches it to the client."/>
     <variant name="ImplThreadTotalLatency"
         summary="the total latency overhead for Compositor-only frames. Which
                  excludes BeginMainFrameQueuing."/>
     <variant name="MainThreadTotalLatency"
         summary="the total latency overhead for frames which had Main-thread
                  work."/>
   </token>
 </histogram>

 <histogram name="CompositorLatency.Type{Sequence}" enum="FrameReportType"
     expires_after="2024-07-21">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Whether frame is dropped or presented meeting or missing the deadline or is
     a compositor only frame.
   </summary>
   <token key="Sequence">
     <variant name="" summary="All Sequences"/>
     <variant name=".AnyInteraction" summary="At least one active interaction"/>
     <variant name=".CanvasAnimation" summary="Main-thread canvas animation"/>
     <variant name=".CompositorAnimation" summary="Compositor-driven animation"/>
     <variant name=".JSAnimation" summary="JS-driven animation"/>
     <variant name=".MainThreadAnimation"
         summary="Main-thread driven animation"/>
     <variant name=".NoInteraction" summary="No active interaction"/>
     <variant name=".PinchZoom" summary="Pinch-to-zoom interaction"/>
     <variant name=".RAF" summary="rAF callback driven animation"/>
     <variant name=".ScrollbarScroll" summary="Scrollbar driven scrolls"/>
     <variant name=".TouchScroll" summary="Touchscreen driven interaction"/>
     <variant name=".Video" summary="Video playback"/>
     <variant name=".WheelScroll" summary="Mousewheel driven interaction"/>
   </token>
 </histogram>

 <histogram name="CompositorLatency{ReportType}{InteractionType}.{StageType}"
     units="microseconds" expires_after="2024-07-24">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the duration of various stages in the pipeline as a single frame goes
     through the various stages in the compositor {ReportType}.

     This metric uses base::Histogram::FactoryMicrosecondsTimeGet so only users
     with high resolution clocks will report this metric.
   </summary>
   <token key="ReportType">
     <variant name=""
         summary="reported for frames that went through all the compositor
                  stages in chromium, and was presented to the user"/>
     <variant name=".DroppedFrame"
         summary="reported for frames that the user did not see: this includes
                  frames that are dropped in various stages inside chromium,
                  or even frames that went through all stages in chromium, but
                  ultimately was not presented to the user"/>
     <variant name=".MissedDeadlineFrame"
         summary="reported for frames that went through all the compositor
                  stages in chromium, and was presented to the user, but were
                  delayed and missed their deadline"/>
   </token>
   <token key="InteractionType">
     <variant name=""/>
     <variant name=".CanvasAnimation"/>
     <variant name=".CompositorAnimation"/>
     <variant name=".JSAnimation"/>
     <variant name=".MainThreadAnimation"/>
     <variant name=".PinchZoom"/>
     <variant name=".RAF"/>
     <variant name=".ScrollbarScroll"/>
     <variant name=".SETCompositorAnimation"/>
     <variant name=".SETMainThreadAnimation"/>
     <variant name=".TouchScroll"/>
     <variant name=".WheelScroll"/>
   </token>
   <token key="StageType">
     <variant name="Activation"/>
     <variant name="BeginImplFrameToSendBeginMainFrame"/>
     <variant name="Commit"/>
     <variant name="EndActivateToSubmitCompositorFrame"/>
     <variant name="EndCommitToActivation"/>
     <variant name="SendBeginMainFrameToCommit"/>
     <variant name="SendBeginMainFrameToCommit.Animate"/>
     <variant name="SendBeginMainFrameToCommit.BeginMainSentToStarted"/>
     <variant name="SendBeginMainFrameToCommit.CompositeCommit"/>
     <variant name="SendBeginMainFrameToCommit.CompositingInputs"/>
     <variant name="SendBeginMainFrameToCommit.HandleInputEvents"/>
     <variant name="SendBeginMainFrameToCommit.LayoutUpdate"/>
     <variant name="SendBeginMainFrameToCommit.Paint"/>
     <variant name="SendBeginMainFrameToCommit.Prepaint"/>
     <variant name="SendBeginMainFrameToCommit.StyleUpdate"/>
     <variant name="SendBeginMainFrameToCommit.UpdateLayers"/>
     <variant name="SubmitCompositorFrameToPresentationCompositorFrame"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.BufferAvailableToBufferReady"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.BufferReadyToLatch"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.LatchToSwapEnd"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.ReceivedCompositorFrameToStartDraw"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.StartDrawToSwapStart"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.SubmitToReceiveCompositorFrame"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.SwapEndToPresentationCompositorFrame"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.SwapStartToBufferAvailable"/>
     <variant
         name="SubmitCompositorFrameToPresentationCompositorFrame.SwapStartToSwapEnd"/>
     <variant name="TotalLatency"/>
   </token>
 </histogram>

 <histogram name="Graphics.Exo.Smoothness.DidNotProduceToFrameArrival"
     units="microseconds" expires_after="2024-05-05">
   <owner>jonross@chromium.org</owner>
   <owner>yzshen@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Measures the time duration between Exo sending a DidNotProduceFrame response
     and the next frame arrival, if the next frame arrives before a new
     BeginFrame request. Reported for clients with high-resolution clocks.

     This metric is used to measure whether the deadline Exo uses to wait for
     frames is reasonable. Please note that a value is reported for each
     DidNotProduceFrame. If (1) DidNotProduceFrame is issued when there are
     already queued BeginFrame requests; or (2) a new BeginFrame request arrives
     before the next frame; or (3) BeginFrame requests are paused, then the value
     reported is 0.
   </summary>
 </histogram>

 <histogram name="Graphics.Exo.Smoothness.PercentDidNotProduceFrame" units="%"
     expires_after="2024-07-07">
   <owner>jonross@chromium.org</owner>
   <owner>yzshen@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the percent of BeginFrame requests that Exo receives and responds
     with DidNotProduceFrame.

     A new value is reported for every 100 BeginFrame requests that a shell
     surface receives. Note that this metric is reported only when there are
     sufficient number of BeginFrame requests (&gt;= 100).
   </summary>
 </histogram>

 <histogram name="Graphics.Exo.Smoothness.PercentFrameDiscarded" units="%"
     expires_after="2024-12-31">
   <owner>jonross@chromium.org</owner>
   <owner>yzshen@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the percent of compositor frames that are submitted from Exo clients
     and directly discarded without being sent to the GPU process.

     A new value is reported for every 100 frames that a shell surface submits.
     Note that this metric is reported only when there are sufficient number of
     frames (&gt;= 100).
   </summary>
 </histogram>

 <histogram name="Graphics.Smoothness.95pctPercentDroppedFrames_1sWindow"
     units="%" expires_after="2024-07-21">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     The percent dropped frame is calculated for each sliding window of 1 second
     length and added to a histogram, and then the 95 percentile of that
     histogram is reported as 95pctPercentDroppedFrames_1sWindow.

     The sliding windows cover the duration of page-load (From start of page-load
     until user navigates away, or closes the tab/chrome, or when app goes to
     background). Note that this means that this metric will bias toward tabs
     that are closed more quickly, and might underreport tabs that remain open
     for a long duration.

     PercentDroppedFrames is measured by tracking the number of frames which were
     not displayed on screen out of the total number of frames expected to be
     produced and displayed. In other words, the lower this number is, the
     smoother experience.
   </summary>
 </histogram>

 <histogram name="Graphics.Smoothness.Checkerboarding3.AllSequences" units="%"
     expires_after="2024-07-07">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the percent of checkerboarded frames for a sequence by aggregating
     all its animations and interactions, where a sequence is a series of frames
     produced which contain at least one of the animations/interactions. Such
     animations and interactions encompass: Compositor-thread animations;
     Main-thread animations; JS animations; scrolling; and pinch-gestures.

     Checkerboarding is measured by tracking the number of times checkerboard
     frames are displayed (as opposed to the number of checkerboard frames
     produced), since the same checkerboard frame can be displayed more than
     once.

     Note that this metric is reported only when there are a sufficient number of
     frames (&gt;= 100). If there are sequences with fewer frames, then these are
     aggregated until an additional sequence completes where there are (&gt;=
     100) frames available in total.
   </summary>
 </histogram>

 <histogram name="Graphics.Smoothness.Checkerboarding3.{Thread}{Sequence}"
     units="%" expires_after="2024-07-07">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the percent of checkerboarded frames for a sequence by aggregating
     all {Sequence}, where a sequence is a series of frames produced which
     contain at least one of the aforementioned effects.

     Checkerboarding is measured by tracking the number of times checkerboard
     frames are displayed (as opposed to the number of checkerboard frames
     produced), since the same checkerboard frame can be displayed more than
     once.

     Note that this metric is reported only when there are a sufficient number of
     frames (&gt;= 100). If there are sequences with fewer frames, then these are
     aggregated until an additional sequence completes where there are (&gt;=
     100) frames available in total.
   </summary>
   <token key="Thread" variants="SmoothnessThread"/>
   <token key="Sequence" variants="SmoothnessSequence"/>
 </histogram>

 <histogram name="Graphics.Smoothness.Jank3.All{Type}" units="%"
     expires_after="2024-06-05">
   <owner>jonross@chromium.org</owner>
   <owner>mjzhang@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the percent of janks for a sequence by aggregating all its {Type}

     Jank is measured by tracking the number of abrupt increases in frame
     presentation interval, divided by the total number of frames expected to be
     produced and displayed. The lower this number is, the less the smoothness
     varies over time.

     Note that this metric is reported only when there are sufficient number of
     frames (&gt;= 100). If there are sequences with fewer frames, then these are
     aggregated until there are enough frames to produce the metric.
   </summary>
   <token key="Type">
     <variant name="Sequences"
         summary="animations and interactions, where a sequence is a series of
                  frames produced which contain at least one of the
                  animations/interactions. Such animations and interactions
                  encompass: Compositor-thread animations; Main-thread
                  animations; JS animations; scrolling; and pinch-gestures."/>
   </token>
 </histogram>

 <histogram name="Graphics.Smoothness.Jank3.{Thread}{Sequence}" units="%"
     expires_after="2024-06-05">
   <owner>jonross@chromium.org</owner>
   <owner>mjzhang@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the percent of janks for a sequence by aggregating all {Sequence},
     where a sequence is a series of frames produced which contain at least one
     of the aforementioned effects.

     Jank is measured by tracking the number of abrupt increases in frame
     presentation interval, divided by the total number of frames expected to be
     produced and displayed. The lower this number is, the less the smoothness
     varies over time.

     Note that this metric is reported only when there are sufficient number of
     frames (&gt;= 100). If there are sequences with fewer frames, then these are
     aggregated until there are enough frames to produce the metric.
   </summary>
   <token key="Thread" variants="SmoothnessThread"/>
   <token key="Sequence" variants="SmoothnessSequence"/>
 </histogram>

 <histogram name="Graphics.Smoothness.MaxPercentDroppedFrames_1sWindow"
     units="%" expires_after="2024-06-30">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the percent of dropped frames for in a 1 second sliding window.

     PercentDroppedFrames is measured by tracking the number of frames which were
     not displayed on screen out of the total number of frames expected to be
     produced and displayed. In other words, the lower this number is, the
     smoother experience.
   </summary>
 </histogram>

 <histogram name="Graphics.Smoothness.MaxStale" units="ms"
     expires_after="2024-07-21">
   <owner>jonross@chromium.org</owner>
   <owner>mjzhang@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the maximum staleness value for all presentations for a particular
     sequence of frames (e.g. during scroll, animation, etc.). This is reported
     in various sub-metrics with suffixes describing the type of the sequence
     (e.g. TouchScroll etc.).

     Typically, a frame presentation is expected to last at least one vsync
     cycle, plus any number of additional vsync cycles if no updates are expected
     duration that time. If the presentation interval is prolonged due to reasons
     other than listed above, then that prolonged portion will be considered
     staleness for that frame.

     Note that this metric is reported only when there are sufficient number of
     frames (&gt;= 100). If there are sequences with fewer frames, then these are
     aggregated until there are enough frames to produce the metric.
   </summary>
 </histogram>

 <histogram name="Graphics.Smoothness.PercentDroppedFrames3.AllSequences"
     units="%" expires_after="never">
 <!-- expires-never: guiding metric (internal: go/chrome-browser-guiding-metrics) -->

   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <owner>chrome-analysis-team@google.com</owner>
   <summary>
     Tracks the percent of dropped frames for a sequence by aggregating all its
     animations and interactions, where a sequence is a series of frames produced
     which contain at least one of the animations/interactions. Such animations
     and interactions encompass: Compositor-thread animations; Main-thread
     animations; JS animations; scrolling; and pinch-gestures.

     PercentDroppedFrames is measured by tracking the number of frames which were
     not displayed on screen out of the total number of frames expected to be
     produced and displayed. In other words, the lower this number is, the
     smoother the experience.

     Note that this metric is reported only when there are a sufficient number of
     frames (&gt;= 100). If there are sequences with fewer frames, then these are
     aggregated until an additional sequence completes where there are (&gt;=
     100) frames available in total.

     This is a new implementation of the older
     Graphics.Smoothness.PercentDroppedFrames.AllInteractions metric.

     See http://shortn/_ItBDdHoyCf (internal only) for more details.

     This histogram is of special interest to the chrome-analysis-team@. Do not
     change its semantics or retire it without talking to them first.
   </summary>
 </histogram>

 <histogram name="Graphics.Smoothness.PercentDroppedFrames3.{Thread}{Sequence}"
     units="%" expires_after="2024-07-14">
   <owner>jonross@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the percent of dropped frames for a sequence by aggregating all
     {Sequence}, where a sequence is a series of frames produced which contain at
     least one of the aforementioned effects.

     PercentDroppedFrames is measured by tracking the number of frames which were
     not displayed on screen out of the total number of frames expected to be
     produced and displayed. In other words, the lower this number is, the
     smoother the experience.

     Note that this metric is reported only when there are a sufficient number of
     frames (&gt;= 100). If there are sequences with fewer frames, then these are
     aggregated until an additional sequence completes where there are (&gt;=
     100) frames available in total.

     This is a new implementation of the older
     Graphics.Smoothness.PercentDroppedFrames.AllInteractions metric.
   </summary>
   <token key="Thread" variants="SmoothnessThread"/>
   <token key="Sequence" variants="SmoothnessSequence"/>
 </histogram>

 <histogram name="Graphics.Smoothness.Stale" units="ms"
     expires_after="2024-07-21">
   <owner>jonross@chromium.org</owner>
   <owner>mjzhang@chromium.org</owner>
   <owner>graphics-dev@chromium.org</owner>
   <summary>
     Tracks the staleness value for each frame presentation for a particular
     sequence of frames (e.g. during scroll, animation, etc.). This is reported
     in various sub-metrics with suffixes describing the type of the sequence
     (e.g. TouchScroll etc.).

     Typically, a frame presentation is expected to last at least one vsync
     cycle, plus any number of additional vsync cycles if no updates are expected
     duration that time. If the presentation interval is prolonged due to reasons
     other than listed above, then that prolonged portion will be considered
     staleness.

     Note that the reporting of this metric occurs as soon as a frame is
     presented, and is not affected by the length of the frame sequence.
   </summary>
 </histogram>

 </histograms>

 </histogram-configuration>