1 files changed, 343 insertions, 0 deletions
diff --git a/gfx/layers/composite/FPSCounter.cpp b/gfx/layers/composite/FPSCounter.cpp
new file mode 100644
index 0000000000..cf3d0725ed
--- /dev/null
+++ b/gfx/layers/composite/FPSCounter.cpp
@@ -0,0 +1,343 @@
+/* -*- 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 <stddef.h>                     // for size_t
+#include "Units.h"                      // for ScreenIntRect
+#include "gfxRect.h"                    // for gfxRect
+#include "mozilla/gfx/Point.h"          // for IntSize, Point
+#include "mozilla/gfx/Rect.h"           // for Rect
+#include "mozilla/gfx/Types.h"          // for Color, SurfaceFormat
+#include "mozilla/layers/Compositor.h"  // for Compositor
+#include "mozilla/layers/CompositorTypes.h"
+#include "mozilla/layers/Effects.h"  // for Effect, EffectChain, etc
+#include "mozilla/StaticPrefs_layers.h"
+#include "mozilla/TimeStamp.h"       // for TimeStamp, TimeDuration
+#include "nsPoint.h"                 // for nsIntPoint
+#include "nsRect.h"                  // for mozilla::gfx::IntRect
+#include "nsIFile.h"                 // for nsIFile
+#include "nsDirectoryServiceDefs.h"  // for NS_OS_TMP_DIR
+#include "mozilla/Sprintf.h"
+#include "FPSCounter.h"
+
+namespace mozilla {
+namespace layers {
+
+using namespace mozilla::gfx;
+
+FPSCounter::FPSCounter(const char* aName)
+    : mWriteIndex(0), mIteratorIndex(-1), mFPSName(aName) {
+  Init();
+}
+
+FPSCounter::~FPSCounter() = default;
+
+void FPSCounter::Init() {
+  for (int i = 0; i < kMaxFrames; i++) {
+    mFrameTimestamps.AppendElement(TimeStamp());
+  }
+  mLastInterval = TimeStamp::Now();
+}
+
+// Returns true if we captured a full interval of data
+bool FPSCounter::CapturedFullInterval(TimeStamp aTimestamp) {
+  TimeDuration duration = aTimestamp - mLastInterval;
+  return duration.ToSeconds() >= kFpsDumpInterval;
+}
+
+void FPSCounter::AddFrame(TimeStamp aTimestamp) {
+  NS_ASSERTION(mWriteIndex < kMaxFrames,
+               "We probably have a bug with the circular buffer");
+  NS_ASSERTION(mWriteIndex >= 0,
+               "Circular Buffer index should never be negative");
+
+  int index = mWriteIndex++;
+  if (mWriteIndex == kMaxFrames) {
+    mWriteIndex = 0;
+  }
+
+  mFrameTimestamps[index] = aTimestamp;
+
+  if (CapturedFullInterval(aTimestamp)) {
+    PrintFPS();
+    WriteFrameTimeStamps();
+    mLastInterval = aTimestamp;
+  }
+}
+
+double FPSCounter::AddFrameAndGetFps(TimeStamp aTimestamp) {
+  AddFrame(aTimestamp);
+  return GetFPS(aTimestamp);
+}
+
+int FPSCounter::GetLatestReadIndex() {
+  if (mWriteIndex == 0) {
+    return kMaxFrames - 1;
+  }
+
+  return mWriteIndex - 1;
+}
+
+TimeStamp FPSCounter::GetLatestTimeStamp() {
+  TimeStamp timestamp = mFrameTimestamps[GetLatestReadIndex()];
+  MOZ_ASSERT(!timestamp.IsNull(), "Cannot use null timestamps");
+  return timestamp;
+}
+
+// Returns true if we iterated over a full interval of data
+bool FPSCounter::IteratedFullInterval(TimeStamp aTimestamp, double aDuration) {
+  MOZ_ASSERT(mIteratorIndex >= 0, "Cannot be negative");
+  MOZ_ASSERT(mIteratorIndex < kMaxFrames,
+             "Iterator index cannot be greater than kMaxFrames");
+
+  TimeStamp currentStamp = mFrameTimestamps[mIteratorIndex];
+  TimeDuration duration = aTimestamp - currentStamp;
+  return duration.ToSeconds() >= aDuration;
+}
+
+void FPSCounter::ResetReverseIterator() {
+  mIteratorIndex = GetLatestReadIndex();
+}
+
+/***
+ * Returns true if we have another timestamp that is valid and
+ * is within the given duration that we're interested in.
+ * Duration is in seconds
+ */
+bool FPSCounter::HasNext(TimeStamp aTimestamp, double aDuration) {
+  // Order of evaluation here has to stay the same
+  // otherwise IteratedFullInterval reads from mFrameTimestamps which cannot
+  // be null
+  return (mIteratorIndex != mWriteIndex)  // Didn't loop around the buffer
+         && !mFrameTimestamps[mIteratorIndex].IsNull()  // valid data
+         && !IteratedFullInterval(aTimestamp, aDuration);
+}
+
+TimeStamp FPSCounter::GetNextTimeStamp() {
+  TimeStamp timestamp = mFrameTimestamps[mIteratorIndex--];
+  MOZ_ASSERT(!timestamp.IsNull(), "Reading Invalid Timestamp Data");
+
+  if (mIteratorIndex == -1) {
+    mIteratorIndex = kMaxFrames - 1;
+  }
+  return timestamp;
+}
+
+/**
+ * GetFPS calculates how many frames we've already composited from the current
+ * frame timestamp and we iterate from the latest timestamp we recorded,
+ * going back in time. When we hit a frame that is longer than the 1 second
+ * from the current composited frame, we return how many frames we've counted.
+ * Just a visualization:
+ *
+ *                                 aTimestamp
+ * Frames: 1 2 3 4 5 6 7 8 9 10 11 12
+ * Time   -------------------------->
+ *
+ * GetFPS iterates from aTimestamp, which is the current frame.
+ * Then starting at frame 12, going back to frame 11, 10, etc, we calculate
+ * the duration of the recorded frame timestamp from aTimestamp.
+ * Once duration is greater than 1 second, we return how many frames
+ * we composited.
+ */
+double FPSCounter::GetFPS(TimeStamp aTimestamp) {
+  int frameCount = 0;
+  int duration = 1.0;  // Only care about the last 1s of data
+
+  ResetReverseIterator();
+  while (HasNext(aTimestamp, duration)) {
+    GetNextTimeStamp();
+    frameCount++;
+  }
+
+  return frameCount;
+}
+
+// Iterate the same way we do in GetFPS()
+int FPSCounter::BuildHistogram(std::map<int, int>& aFpsData) {
+  TimeStamp currentIntervalStart = GetLatestTimeStamp();
+  TimeStamp currentTimeStamp = GetLatestTimeStamp();
+  TimeStamp startTimeStamp = GetLatestTimeStamp();
+
+  int frameCount = 0;
+  int totalFrameCount = 0;
+
+  ResetReverseIterator();
+  while (HasNext(startTimeStamp)) {
+    currentTimeStamp = GetNextTimeStamp();
+    TimeDuration interval = currentIntervalStart - currentTimeStamp;
+
+    if (interval.ToSeconds() >= 1.0) {
+      currentIntervalStart = currentTimeStamp;
+      aFpsData[frameCount]++;
+      frameCount = 0;
+    }
+
+    frameCount++;
+    totalFrameCount++;
+  }
+
+  TimeDuration totalTime = currentIntervalStart - currentTimeStamp;
+  printf_stderr("Discarded %d frames over %f ms in histogram for %s\n",
+                frameCount, totalTime.ToMilliseconds(), mFPSName);
+  return totalFrameCount;
+}
+
+// Iterate the same way we do in GetFPS()
+void FPSCounter::WriteFrameTimeStamps(PRFileDesc* fd) {
+  const int bufferSize = 256;
+  char buffer[bufferSize];
+  int writtenCount = SprintfLiteral(buffer, "FPS Data for: %s\n", mFPSName);
+  MOZ_ASSERT(writtenCount < bufferSize);
+  if (writtenCount >= bufferSize) {
+    return;
+  }
+  PR_Write(fd, buffer, writtenCount);
+
+  ResetReverseIterator();
+  TimeStamp startTimeStamp = GetLatestTimeStamp();
+
+  MOZ_ASSERT(HasNext(startTimeStamp));
+  TimeStamp previousSample = GetNextTimeStamp();
+
+  MOZ_ASSERT(HasNext(startTimeStamp));
+  TimeStamp nextTimeStamp = GetNextTimeStamp();
+
+  while (HasNext(startTimeStamp)) {
+    TimeDuration duration = previousSample - nextTimeStamp;
+    writtenCount = SprintfLiteral(buffer, "%f,\n", duration.ToMilliseconds());
+    MOZ_ASSERT(writtenCount < bufferSize);
+    if (writtenCount >= bufferSize) {
+      continue;
+    }
+    PR_Write(fd, buffer, writtenCount);
+
+    previousSample = nextTimeStamp;
+    nextTimeStamp = GetNextTimeStamp();
+  }
+}
+
+double FPSCounter::GetMean(std::map<int, int> aHistogram) {
+  double average = 0.0;
+  double samples = 0.0;
+
+  for (std::map<int, int>::iterator iter = aHistogram.begin();
+       iter != aHistogram.end(); ++iter) {
+    int fps = iter->first;
+    int count = iter->second;
+
+    average += fps * count;
+    samples += count;
+  }
+
+  return average / samples;
+}
+
+double FPSCounter::GetStdDev(std::map<int, int> aHistogram) {
+  double sumOfDifferences = 0;
+  double average = GetMean(aHistogram);
+  double samples = 0.0;
+
+  for (std::map<int, int>::iterator iter = aHistogram.begin();
+       iter != aHistogram.end(); ++iter) {
+    int fps = iter->first;
+    int count = iter->second;
+
+    double diff = ((double)fps) - average;
+    diff *= diff;
+
+    for (int i = 0; i < count; i++) {
+      sumOfDifferences += diff;
+    }
+    samples += count;
+  }
+
+  double stdDev = sumOfDifferences / samples;
+  return sqrt(stdDev);
+}
+
+void FPSCounter::PrintFPS() {
+  if (!StaticPrefs::layers_acceleration_draw_fps_print_histogram()) {
+    return;
+  }
+
+  std::map<int, int> histogram;
+  int totalFrames = BuildHistogram(histogram);
+
+  TimeDuration measurementInterval =
+      mFrameTimestamps[GetLatestReadIndex()] - mLastInterval;
+  printf_stderr("FPS for %s. Total Frames: %d Time Interval: %f seconds\n",
+                mFPSName, totalFrames,
+                measurementInterval.ToSecondsSigDigits());
+
+  PrintHistogram(histogram);
+}
+
+void FPSCounter::PrintHistogram(std::map<int, int>& aHistogram) {
+  if (aHistogram.empty()) {
+    return;
+  }
+
+  int length = 0;
+  const int kBufferLength = 512;
+  int availableSpace = kBufferLength;
+  char buffer[kBufferLength];
+
+  for (std::map<int, int>::iterator iter = aHistogram.begin();
+       iter != aHistogram.end(); iter++) {
+    int fps = iter->first;
+    int count = iter->second;
+
+    int lengthRequired =
+        snprintf(buffer + length, availableSpace, "FPS: %d = %d. ", fps, count);
+    // Ran out of buffer space. Oh well - just print what we have.
+    if (lengthRequired > availableSpace) {
+      break;
+    }
+    length += lengthRequired;
+    availableSpace -= lengthRequired;
+  }
+
+  printf_stderr("%s\n", buffer);
+  printf_stderr("Mean: %f , std dev %f\n", GetMean(aHistogram),
+                GetStdDev(aHistogram));
+}
+
+// Write FPS timestamp data to a file only if
+// draw-fps.write-to-file is true
+nsresult FPSCounter::WriteFrameTimeStamps() {
+  if (!StaticPrefs::layers_acceleration_draw_fps_write_to_file()) {
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(mWriteIndex == 0);
+
+  nsCOMPtr<nsIFile> resultFile;
+  nsresult rv =
+      NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(resultFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!strncmp(mFPSName, "Compositor", strlen(mFPSName))) {
+    resultFile->Append(u"fps.txt"_ns);
+  } else {
+    resultFile->Append(u"txn.txt"_ns);
+  }
+
+  PRFileDesc* fd = nullptr;
+  int mode = 644;
+  int openFlags = PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE;
+  rv = resultFile->OpenNSPRFileDesc(openFlags, mode, &fd);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  WriteFrameTimeStamps(fd);
+  PR_Close(fd);
+
+  printf_stderr("Wrote FPS data to file: %s\n",
+                resultFile->HumanReadablePath().get());
+  return NS_OK;
+}
+
+}  // end namespace layers
+}  // end namespace mozilla