Bug 1772216: Add telemetry probe to measure time spent waiting for th…

…e GPU. r=mstange

Differential Revision: https://phabricator.services.mozilla.com/D148075

gfx/metrics.yaml

@@ -28,6 +28,22 @@ paint:
     telemetry_mirror: PAINT_BUILD_DISPLAYLIST_TIME
 
 wr:
+  gpu_wait_time:
+    type: timing_distribution
+    description: >
+      The time spent waiting for the GPU to complete previously issued drawing
+      commands.
+    time_unit: microsecond
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1772216
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1772216
+    data_sensitivity:
+      - technical
+    notification_emails:
+      - [email protected]
+    expires: never
+    telemetry_mirror: WR_GPU_WAIT_TIME
   rasterize_glyphs_time:
     type: timing_distribution
     description: >

gfx/webrender_bindings/RenderThread.cpp

@@ -17,6 +17,7 @@
 #include "mozilla/gfx/gfxVars.h"
 #include "mozilla/gfx/GPUParent.h"
 #include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/glean/GleanMetrics.h"
 #include "mozilla/layers/CompositableInProcessManager.h"
 #include "mozilla/layers/CompositorThread.h"
 #include "mozilla/layers/CompositorBridgeParent.h"
@@ -564,7 +565,9 @@ void RenderThread::UpdateAndRender(
     // The wait is necessary for Textures recycling of AsyncImagePipelineManager
     // and for avoiding GPU queue is filled with too much tasks.
     // WaitForGPU's implementation is different for each platform.
+    auto timerId = glean::wr::gpu_wait_time.Start();
     renderer->WaitForGPU();
+    glean::wr::gpu_wait_time.StopAndAccumulate(std::move(timerId));
   } else {
     // Update frame id for NotifyPipelinesUpdated() when rendering does not
     // happen, either because rendering was not requested or the frame was

toolkit/components/telemetry/Histograms.json

@@ -16090,6 +16090,17 @@
     "labels": ["NoOverflow", "Desktop", "ButNotMinScaleSize", "MinScaleSize"],
     "description": "How common are different types of out-of-reach viewport overflow?"
   },
+  "WR_GPU_WAIT_TIME": {
+    "record_in_processes": [ "main", "gpu" ],
+    "products": [ "firefox", "fennec", "geckoview_streaming" ],
+    "alert_emails": [ "[email protected]" ],
+    "bug_numbers": [ 1772216 ],
+    "expires_in_version": "never",
+    "kind": "exponential",
+    "high": 1000,
+    "n_buckets": 50,
+    "description": "The time spent waiting for the GPU to complete previously issued drawing commands in milliseconds"
+  },
   "WR_SCENEBUILD_TIME": {
     "record_in_processes": ["main", "gpu"],
     "products": ["firefox", "fennec", "geckoview_streaming"],