1 files changed, 195 insertions, 0 deletions
diff --git a/gfx/layers/apz/src/CheckerboardEvent.cpp b/gfx/layers/apz/src/CheckerboardEvent.cpp
new file mode 100644
index 0000000000..8f518c7383
--- /dev/null
+++ b/gfx/layers/apz/src/CheckerboardEvent.cpp
@@ -0,0 +1,195 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CheckerboardEvent.h"
+#include "mozilla/Logging.h"
+
+#include <algorithm>  // for std::sort
+
+static mozilla::LazyLogModule sApzCheckLog("apz.checkerboard");
+
+namespace mozilla {
+namespace layers {
+
+// Relatively arbitrary limit to prevent a perma-checkerboard event from
+// eating up gobs of memory. Ideally we shouldn't have perma-checkerboarding
+// but better to guard against it.
+#define LOG_LENGTH_LIMIT (50 * 1024)
+
+const char* CheckerboardEvent::sDescriptions[] = {
+    "page",
+    "painted displayport",
+    "requested displayport",
+    "viewport",
+};
+
+const char* CheckerboardEvent::sColors[] = {
+    "brown",
+    "lightgreen",
+    "yellow",
+    "red",
+};
+
+CheckerboardEvent::CheckerboardEvent(bool aRecordTrace)
+    : mRecordTrace(aRecordTrace),
+      mOriginTime(TimeStamp::Now()),
+      mCheckerboardingActive(false),
+      mLastSampleTime(mOriginTime),
+      mFrameCount(0),
+      mTotalPixelMs(0),
+      mPeakPixels(0),
+      mRendertraceLock("Rendertrace") {}
+
+uint32_t CheckerboardEvent::GetSeverity() {
+  // Scale the total into a 32-bit value
+  return (uint32_t)sqrt((double)mTotalPixelMs);
+}
+
+uint32_t CheckerboardEvent::GetPeak() { return mPeakPixels; }
+
+TimeDuration CheckerboardEvent::GetDuration() { return mEndTime - mStartTime; }
+
+std::string CheckerboardEvent::GetLog() {
+  MonitorAutoLock lock(mRendertraceLock);
+  return mRendertraceInfo.str();
+}
+
+bool CheckerboardEvent::IsRecordingTrace() { return mRecordTrace; }
+
+void CheckerboardEvent::UpdateRendertraceProperty(
+    RendertraceProperty aProperty, const CSSRect& aRect,
+    const std::string& aExtraInfo) {
+  if (!mRecordTrace) {
+    return;
+  }
+  MonitorAutoLock lock(mRendertraceLock);
+  if (!mCheckerboardingActive) {
+    mBufferedProperties[aProperty].Update(aProperty, aRect, aExtraInfo, lock);
+  } else {
+    LogInfo(aProperty, TimeStamp::Now(), aRect, aExtraInfo, lock);
+  }
+}
+
+void CheckerboardEvent::LogInfo(RendertraceProperty aProperty,
+                                const TimeStamp& aTimestamp,
+                                const CSSRect& aRect,
+                                const std::string& aExtraInfo,
+                                const MonitorAutoLock& aProofOfLock) {
+  MOZ_ASSERT(mRecordTrace);
+  if (mRendertraceInfo.tellp() >= LOG_LENGTH_LIMIT) {
+    // The log is already long enough, don't put more things into it. We'll
+    // append a truncation message when this event ends.
+    return;
+  }
+  // The log is consumed by the page at about:checkerboard. The format is not
+  // formally specced, but an informal description can be found at
+  // https://searchfox.org/mozilla-central/rev/d866b96d74ec2a63f09ee418f048d23f4fd379a2/toolkit/components/aboutcheckerboard/content/aboutCheckerboard.js#86
+  mRendertraceInfo << "RENDERTRACE "
+                   << (aTimestamp - mOriginTime).ToMilliseconds() << " rect "
+                   << sColors[aProperty] << " " << aRect.X() << " " << aRect.Y()
+                   << " " << aRect.Width() << " " << aRect.Height() << " "
+                   << "// " << sDescriptions[aProperty] << aExtraInfo
+                   << std::endl;
+}
+
+bool CheckerboardEvent::RecordFrameInfo(uint32_t aCssPixelsCheckerboarded) {
+  TimeStamp sampleTime = TimeStamp::Now();
+  bool eventEnding = false;
+  if (aCssPixelsCheckerboarded > 0) {
+    if (!mCheckerboardingActive) {
+      StartEvent();
+    }
+    MOZ_ASSERT(mCheckerboardingActive);
+    MOZ_ASSERT(sampleTime >= mLastSampleTime);
+    mTotalPixelMs +=
+        (uint64_t)((sampleTime - mLastSampleTime).ToMilliseconds() *
+                   aCssPixelsCheckerboarded);
+    if (aCssPixelsCheckerboarded > mPeakPixels) {
+      mPeakPixels = aCssPixelsCheckerboarded;
+    }
+    mFrameCount++;
+  } else {
+    if (mCheckerboardingActive) {
+      StopEvent();
+      eventEnding = true;
+    }
+    MOZ_ASSERT(!mCheckerboardingActive);
+  }
+  mLastSampleTime = sampleTime;
+  return eventEnding;
+}
+
+void CheckerboardEvent::StartEvent() {
+  MOZ_LOG(sApzCheckLog, LogLevel::Debug, ("Starting checkerboard event"));
+  MOZ_ASSERT(!mCheckerboardingActive);
+  mCheckerboardingActive = true;
+  mStartTime = TimeStamp::Now();
+
+  if (!mRecordTrace) {
+    return;
+  }
+  MonitorAutoLock lock(mRendertraceLock);
+  std::vector<PropertyValue> history;
+  for (PropertyBuffer& bufferedProperty : mBufferedProperties) {
+    bufferedProperty.Flush(history, lock);
+  }
+  std::sort(history.begin(), history.end());
+  for (const PropertyValue& p : history) {
+    LogInfo(p.mProperty, p.mTimeStamp, p.mRect, p.mExtraInfo, lock);
+  }
+  mRendertraceInfo << " -- checkerboarding starts below --" << std::endl;
+}
+
+void CheckerboardEvent::StopEvent() {
+  MOZ_LOG(sApzCheckLog, LogLevel::Debug, ("Stopping checkerboard event"));
+  mCheckerboardingActive = false;
+  mEndTime = TimeStamp::Now();
+
+  if (!mRecordTrace) {
+    return;
+  }
+  MonitorAutoLock lock(mRendertraceLock);
+  if (mRendertraceInfo.tellp() >= LOG_LENGTH_LIMIT) {
+    mRendertraceInfo << "[logging aborted due to length limitations]\n";
+  }
+  mRendertraceInfo << "Checkerboarded for " << mFrameCount << " frames ("
+                   << (mEndTime - mStartTime).ToMilliseconds() << " ms), "
+                   << mPeakPixels << " peak, " << GetSeverity() << " severity."
+                   << std::endl;
+}
+
+bool CheckerboardEvent::PropertyValue::operator<(
+    const PropertyValue& aOther) const {
+  if (mTimeStamp < aOther.mTimeStamp) {
+    return true;
+  } else if (mTimeStamp > aOther.mTimeStamp) {
+    return false;
+  }
+  return mProperty < aOther.mProperty;
+}
+
+CheckerboardEvent::PropertyBuffer::PropertyBuffer() : mIndex(0) {}
+
+void CheckerboardEvent::PropertyBuffer::Update(
+    RendertraceProperty aProperty, const CSSRect& aRect,
+    const std::string& aExtraInfo, const MonitorAutoLock& aProofOfLock) {
+  mValues[mIndex] = {aProperty, TimeStamp::Now(), aRect, aExtraInfo};
+  mIndex = (mIndex + 1) % BUFFER_SIZE;
+}
+
+void CheckerboardEvent::PropertyBuffer::Flush(
+    std::vector<PropertyValue>& aOut, const MonitorAutoLock& aProofOfLock) {
+  for (uint32_t i = 0; i < BUFFER_SIZE; i++) {
+    uint32_t ix = (mIndex + i) % BUFFER_SIZE;
+    if (!mValues[ix].mTimeStamp.IsNull()) {
+      aOut.push_back(mValues[ix]);
+      mValues[ix].mTimeStamp = TimeStamp();
+    }
+  }
+}
+
+}  // namespace layers
+}  // namespace mozilla