bin/ui/tests/performance/process_scenic_trace.go - garnet - Git at Google

 // Copyright 2018 The Fuchsia Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 // process_scenic_trace.go
 //
 // Usage:
 //
 // /pkgfs/packages/scenic_benchmarks/0/bin/process_scenic_trace [-test_suite_name=label] [-benchmarks_out_filename=output_file] [-flutter_app_name=app_name] trace_filename
 //
 // output = Optional: A file to output results to.
 // app_name = Optional: The name of the flutter app to measure fps for.
 // label = Optional: The name of the test suite.
 // trace_filename = The input trace files.
 //
 // The output is a JSON file with benchmark statistics.

 package main

 import (
 	"flag"
 	"fmt"
 	"io/ioutil"
 	"log"
 	"math"
 	"os"
 	"sort"
 	"strings"

 	"fuchsia.googlesource.com/benchmarking"
 )

 const OneSecInUsecs float64 = 1000000
 const OneMsecInUsecs float64 = 1000

 var (
 	verbose = false
 )

 func check(e error) {
 	if e != nil {
 		panic(e)
 	}
 }

 // Sorting helpers.
 type ByStartTime []benchmarking.Event

 func (a ByStartTime) Len() int           { return len(a) }
 func (a ByStartTime) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
 func (a ByStartTime) Less(i, j int) bool { return a[i].Start < a[j].Start }

 func calculateFpsForEvents(fpsEvents []benchmarking.Event) (fps float64, fpsPerWindow []float64) {
 	events := make([]benchmarking.Event, len(fpsEvents))
 	copy(events, fpsEvents)
 	sort.Sort(ByStartTime(events))
 	baseTime := events[0].Start

 	// window = one-second time window
 	const WindowLength float64 = OneSecInUsecs
 	fpsPerWindow = make([]float64, 0)
 	windowEndTime := baseTime + WindowLength

 	numFramesInWindow := 0.0
 	numFrames := 0.0

 	for _, event := range events {
 		if event.Start < windowEndTime {
 			numFramesInWindow++
 			numFrames++
 		} else {
 			for windowEndTime < event.Start {
 				fpsPerWindow = append(fpsPerWindow, numFramesInWindow)
 				windowEndTime += WindowLength
 				numFramesInWindow = 0
 			}
 		}
 	}
 	lastEventTime := events[len(events)-1].Start

 	for windowEndTime < lastEventTime {
 		fpsPerWindow = append(fpsPerWindow, numFramesInWindow)
 		windowEndTime += WindowLength
 		numFramesInWindow = 0
 	}
 	fps = float64(numFrames) / ((lastEventTime - baseTime) / OneSecInUsecs)
 	return fps, fpsPerWindow
 }

 // Returns the overall fps and an array of fps per one second window for the
 // given events.
 func calculateFps(model benchmarking.Model, fpsEventCat string, fpsEventName string) (fps float64, fpsPerWindow []float64) {
 	fpsEvents := model.FindEvents(benchmarking.EventsFilter{Cat: &fpsEventCat, Name: &fpsEventName})
 	return calculateFpsForEvents(fpsEvents)
 }

 // The Go JSON encoder will not work if any of the values are NaN, so use 0 in
 // those cases instead.
 func jsonFloat(num float64) float64 {
 	if math.IsNaN(num) || math.IsInf(num, 0) {
 		return 0
 	} else {
 		return num
 	}
 }

 // Return all pids that start with |prefix|.
 func getProcessesWithPrefix(model benchmarking.Model, prefix string) []benchmarking.Process {
 	result := make([]benchmarking.Process, 0)
 	for _, process := range model.Processes {
 		if strings.HasPrefix(process.Name, prefix) {
 			result = append(result, process)
 		}
 	}
 	return result
 }

 // Project |events| to just their durations, i.e. |events[i].Dur|.
 func extractDurations(events []benchmarking.Event) []float64 {
 	result := make([]float64, len(events))
 	for i, e := range events {
 		result[i] = e.Dur
 	}
 	return result
 }

 // Convert an array of values in microseconds to milliseconds.
 func convertMicrosToMillis(array []float64) []float64 {
 	result := make([]float64, len(array))
 	for i, item := range array {
 		result[i] = item / OneMsecInUsecs
 	}
 	return result
 }

 // Compute the average of an array of floats.
 func computeAverage(array []float64) float64 {
 	result := 0.0
 	for _, item := range array {
 		result += item
 	}
 	return result / float64(len(array))
 }

 // Compute the minimum element of |array|.
 func computeMin(array []float64) float64 {
 	result := math.MaxFloat64
 	for _, item := range array {
 		if item < result {
 			result = item
 		}
 	}
 	return result
 }

 // Compute the maximum element of |array|.
 func computeMax(array []float64) float64 {
 	result := -math.MaxFloat64
 	for _, item := range array {
 		if item > result {
 			result = item
 		}
 	}
 	return result
 }

 // [x for x in array if x >= threshold]
 func filterByThreshold(array []float64, threshold float64) []float64 {
 	result := make([]float64, 0)
 	for _, item := range array {
 		if item >= threshold {
 			result = append(result, item)
 		}
 	}
 	return result
 }

 // Compute the |targetPercentile|th percentile of |array|.
 func computePercentile(array []float64, targetPercentile int) float64 {
 	if len(array) == 0 {
 		panic("Cannot compute the percentile of an empty array")
 	}
 	sort.Float64s(array)
 	if targetPercentile == 100 {
 		return array[len(array)-1]
 	}
 	indexAsFloat, fractional := math.Modf((float64(len(array)) - 1.0) * (0.01 * float64(targetPercentile)))
 	index := int(indexAsFloat)
 	if len(array) == index+1 {
 		return array[index]
 	}
 	return array[index]*(1-fractional) + array[index+1]*fractional
 }

 func averageGap(events []benchmarking.Event, cat1 string, name1 string, cat2 string, name2 string) float64 {
 	gapStart := 0.0
 	totalTime := 0.0
 	numOfGaps := 0.0

 	for _, event := range events {
 		if event.Cat == cat1 && event.Name == name1 {
 			gapStart = event.Start + event.Dur
 		} else if event.Cat == cat2 && event.Name == name2 &&
 			gapStart != 0.0 {
 			if event.Start > gapStart {
 				totalTime += (event.Start - gapStart)
 				numOfGaps++
 			}
 			gapStart = 0.0
 		}
 	}
 	return totalTime / numOfGaps
 }

 // Compute the FPS within Scenic for |trace|, also writing results to
 // |results| if provided.
 func reportScenicFps(model benchmarking.Model, testSuite string, testResultsFile *benchmarking.TestResultsFile) {
 	fmt.Printf("=== Scenic FPS ===\n")
 	fps, fpsPerTimeWindow := calculateFps(model, "gfx", "FramePresented")
 	fmt.Printf("%.4gfps\nfps per one-second window: %v\n", fps, fpsPerTimeWindow)

 	testResultsFile.Add(&benchmarking.TestCaseResults{
 		Label:     "fps",
 		TestSuite: testSuite,
 		Unit:      benchmarking.FramesPerSecond,
 		Values:    []float64{jsonFloat(fps)},
 	})

 	testResultsFile.Add(&benchmarking.TestCaseResults{
 		Label:     "minimum_fps_per_one_second_time_window",
 		TestSuite: testSuite,
 		Unit:      benchmarking.FramesPerSecond,
 		Values:    []float64{jsonFloat(computeMin(fpsPerTimeWindow))},
 	})

 	fmt.Printf("\n== Average times ==\n")
 	type AverageEvent struct {
 		IndentLevel int
 		Name        string
 		Label       string
 	}

 	// List the events we want to include in output. Events are described with:
 	//   Indentation level in output
 	//   Event name in trace
 	//   Event name in output (blank if same as event name in trace)
 	averageEvents := []AverageEvent{
 		{0, "RenderFrame", ""},
 		{1, "ApplyScheduledSessionUpdates", ""},
 		{2, "escher::CommandBuffer::Submit", "CommandBuffer::Submit"},
 		{1, "UpdateAndDeliverMetrics", ""},
 		{1, "EngineRenderer::RenderLayers", ""},
 		{0, "Scenic Compositor", "Escher GPU time"},
 	}

 	gfxStr := "gfx"
 	for _, e := range averageEvents {
 		events := model.FindEvents(benchmarking.EventsFilter{Cat: &gfxStr, Name: &e.Name})
 		durations := convertMicrosToMillis(extractDurations(events))
 		avgDuration := jsonFloat(benchmarking.AvgDuration(events) / OneMsecInUsecs)
 		if e.Label == "" {
 			e.Label = e.Name
 		}
 		fmt.Printf("%-35s %.4gms\n", strings.Repeat("  ", e.IndentLevel)+e.Label,
 			avgDuration)
 		if len(durations) == 0 {
 			fmt.Fprintf(os.Stderr, "Warning: no values found for %s. Falling back to a zero value.\n", e.Label)
 			durations = []float64{0}
 		}
 		testResultsFile.Add(&benchmarking.TestCaseResults{
 			Label:     e.Label,
 			TestSuite: testSuite,
 			Unit:      benchmarking.Milliseconds,
 			Values:    durations,
 		})
 	}
 	renderFrameStr := "RenderFrame"
 	scenicCompositorStr := "Scenic Compositor"
 	events := model.FindEvents(benchmarking.EventsFilter{Cat: &gfxStr, Name: &renderFrameStr})
 	events = append(events, model.FindEvents(benchmarking.EventsFilter{Cat: &gfxStr, Name: &scenicCompositorStr})...)
 	sort.Sort(ByStartTime(events))

 	fmt.Printf("%-35s %.4gms\n", "unaccounted (mostly gfx driver)",
 		jsonFloat(averageGap(events, gfxStr, renderFrameStr, gfxStr, scenicCompositorStr)/OneMsecInUsecs))
 }

 func reportFlutterFpsForInstance(model benchmarking.Model, testSuite string, testResultsFile *benchmarking.TestResultsFile, uiThread benchmarking.Thread, gpuThread benchmarking.Thread, metricNamePrefix string) {
 	fmt.Printf("=== Flutter FPS (%s) ===\n", metricNamePrefix)
 	flutterStr := "flutter"
 	vsyncCallbackStr := "vsync callback"
 	vsyncEvents := uiThread.FindEvents(benchmarking.EventsFilter{Cat: &flutterStr, Name: &vsyncCallbackStr})
 	fps, fpsPerTimeWindow := calculateFpsForEvents(vsyncEvents)
 	fmt.Printf("%.4gfps\nfps per one-second window: %v\n", fps, fpsPerTimeWindow)

 	testResultsFile.Add(&benchmarking.TestCaseResults{
 		Label:     metricNamePrefix + "_fps",
 		TestSuite: testSuite,
 		Unit:      benchmarking.FramesPerSecond,
 		Values:    []float64{jsonFloat(fps)},
 	})

 	testResultsFile.Add(&benchmarking.TestCaseResults{
 		Label:     metricNamePrefix + "_minimum_fps_per_one_second_time_window",
 		TestSuite: testSuite,
 		Unit:      benchmarking.FramesPerSecond,
 		Values:    []float64{jsonFloat(computeMin(fpsPerTimeWindow))},
 	})

 	frameStr := "vsync callback"
 	frameEvents := uiThread.FindEvents(benchmarking.EventsFilter{Name: &frameStr})

 	frameDurations := convertMicrosToMillis(extractDurations(frameEvents))

 	drawStr := "GPURasterizer::Draw"
 	rasterizerEvents := gpuThread.FindEvents(benchmarking.EventsFilter{Name: &drawStr})
 	rasterizerDurations := convertMicrosToMillis(extractDurations(rasterizerEvents))

 	type Metric struct {
 		Name   string
 		Values []float64
 	}

 	metrics := []Metric{
 		{"frame_build_times", frameDurations},
 		{"frame_rasterizer_times", rasterizerDurations},
 	}
 	for _, metric := range metrics {
 		fullName := metricNamePrefix + "_" + metric.Name
 		fmt.Printf("%s: %4g\n", fullName, computeAverage(metric.Values))
 		testResultsFile.Add(&benchmarking.TestCaseResults{
 			Label:     fullName,
 			TestSuite: testSuite,
 			Unit:      benchmarking.Unit(benchmarking.Milliseconds),
 			Values:    metric.Values,
 		})
 	}
 }

 func getThreadsWithPrefixAndSuffix(process benchmarking.Process, prefix string, suffix string) []benchmarking.Thread {
 	threads := make([]benchmarking.Thread, 0)
 	for _, thread := range process.Threads {
 		if strings.HasPrefix(thread.Name, prefix) && strings.HasSuffix(thread.Name, suffix) {
 			threads = append(threads, thread)
 		}
 	}
 	return threads
 }

 func reportFlutterFps(model benchmarking.Model, testSuite string, testResultsFile *benchmarking.TestResultsFile, flutterAppName string) {
 	flutterProcesses := getProcessesWithPrefix(model, "io.flutter.runner")
 	for _, flutterProcess := range flutterProcesses {
 		gpuThreads := getThreadsWithPrefixAndSuffix(flutterProcess, flutterAppName, ".gpu")
 		uiThreads := getThreadsWithPrefixAndSuffix(flutterProcess, flutterAppName, ".ui")
 		if len(gpuThreads) != len(uiThreads) {
 			panic("Unequal ui threads and gpu threads")
 		}

 		for i, uiThread := range uiThreads {
 			// TODO: We are assuming that threads are in order, instead we should verify
 			// that they have the same name % suffix
 			gpuThread := gpuThreads[i]
 			metricNamePrefix := strings.Split(uiThread.Name, ".")[0]
 			reportFlutterFpsForInstance(model, testSuite, testResultsFile, uiThread, gpuThread, metricNamePrefix)
 			// TODO: Decide how to handle multiple flutter apps that match the
 			// target app name. Just report the first one for now.
 			return
 		}
 	}
 	fmt.Printf("Did not find any processes that matched %s\n", flutterAppName)
 }

 func main() {
 	// Argument handling.
 	verbosePtr := flag.Bool("v", false, "Run with verbose logging")
 	flutterAppNamePtr := flag.String("flutter_app_name", "", "Optional: The name of the flutter app to measure fps for.")
 	testSuitePtr := flag.String("test_suite_name", "", "Optional: The name of the test suite.")
 	outputFilenamePtr := flag.String("benchmarks_out_filename", "", "Optional: A file to output results to.")

 	flag.Parse()
 	if flag.NArg() == 0 {
 		flag.Usage()
 		println("  trace_filename: The input trace file.")
 		os.Exit(1)
 	}

 	verbose = *verbosePtr
 	inputFilename := flag.Args()[0]
 	flutterAppName := *flutterAppNamePtr
 	testSuite := *testSuitePtr
 	outputFilename := *outputFilenamePtr

 	traceFile, err := ioutil.ReadFile(inputFilename)
 	check(err)

 	// Creating the trace model.
 	var model benchmarking.Model
 	model, err = benchmarking.ReadTrace(traceFile)
 	check(err)

 	if len(model.Processes) == 0 {
 		panic("No processes found in the model")
 	}

 	var testResultsFile benchmarking.TestResultsFile
 	reportScenicFps(model, testSuite, &testResultsFile)
 	reportFlutterFps(model, testSuite, &testResultsFile, flutterAppName)

 	if outputFilename != "" {
 		outputFile, err := os.Create(outputFilename)
 		if err != nil {
 			log.Fatalf("failed to create file %s", outputFilename)
 		}

 		if err := testResultsFile.Encode(outputFile); err != nil {
 			log.Fatalf("failed to write results to %s: %v", outputFilename, err)
 		}
 		if err := outputFile.Close(); err != nil {
 			log.Fatalf("failed to close results file %s: %v", outputFilename, err)
 		}

 		fmt.Printf("\n\nWrote benchmark values to file '%s'.\n", outputFilename)
 	}
 }
	// Copyright 2018 The Fuchsia Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	// process_scenic_trace.go
	//
	// Usage:
	//
	// /pkgfs/packages/scenic_benchmarks/0/bin/process_scenic_trace [-test_suite_name=label] [-benchmarks_out_filename=output_file] [-flutter_app_name=app_name] trace_filename
	//
	// output = Optional: A file to output results to.
	// app_name = Optional: The name of the flutter app to measure fps for.
	// label = Optional: The name of the test suite.
	// trace_filename = The input trace files.
	//
	// The output is a JSON file with benchmark statistics.

	package main

	import (
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"math"
	"os"
	"sort"
	"strings"

	"fuchsia.googlesource.com/benchmarking"
	)

	const OneSecInUsecs float64 = 1000000
	const OneMsecInUsecs float64 = 1000

	var (
	verbose = false
	)

	func check(e error) {
	if e != nil {
	panic(e)
	}
	}

	// Sorting helpers.
	type ByStartTime []benchmarking.Event

	func (a ByStartTime) Len() int { return len(a) }
	func (a ByStartTime) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
	func (a ByStartTime) Less(i, j int) bool { return a[i].Start < a[j].Start }

	func calculateFpsForEvents(fpsEvents []benchmarking.Event) (fps float64, fpsPerWindow []float64) {
	events := make([]benchmarking.Event, len(fpsEvents))
	copy(events, fpsEvents)
	sort.Sort(ByStartTime(events))
	baseTime := events[0].Start

	// window = one-second time window
	const WindowLength float64 = OneSecInUsecs
	fpsPerWindow = make([]float64, 0)
	windowEndTime := baseTime + WindowLength

	numFramesInWindow := 0.0
	numFrames := 0.0

	for _, event := range events {
	if event.Start < windowEndTime {
	numFramesInWindow++
	numFrames++
	} else {
	for windowEndTime < event.Start {
	fpsPerWindow = append(fpsPerWindow, numFramesInWindow)
	windowEndTime += WindowLength
	numFramesInWindow = 0
	}
	}
	}
	lastEventTime := events[len(events)-1].Start

	for windowEndTime < lastEventTime {
	fpsPerWindow = append(fpsPerWindow, numFramesInWindow)
	windowEndTime += WindowLength
	numFramesInWindow = 0
	}
	fps = float64(numFrames) / ((lastEventTime - baseTime) / OneSecInUsecs)
	return fps, fpsPerWindow
	}

	// Returns the overall fps and an array of fps per one second window for the
	// given events.
	func calculateFps(model benchmarking.Model, fpsEventCat string, fpsEventName string) (fps float64, fpsPerWindow []float64) {
	fpsEvents := model.FindEvents(benchmarking.EventsFilter{Cat: &fpsEventCat, Name: &fpsEventName})
	return calculateFpsForEvents(fpsEvents)
	}

	// The Go JSON encoder will not work if any of the values are NaN, so use 0 in
	// those cases instead.
	func jsonFloat(num float64) float64 {
	if math.IsNaN(num) \|\| math.IsInf(num, 0) {
	return 0
	} else {
	return num
	}
	}

	// Return all pids that start with \|prefix\|.
	func getProcessesWithPrefix(model benchmarking.Model, prefix string) []benchmarking.Process {
	result := make([]benchmarking.Process, 0)
	for _, process := range model.Processes {
	if strings.HasPrefix(process.Name, prefix) {
	result = append(result, process)
	}
	}
	return result
	}

	// Project \|events\| to just their durations, i.e. \|events[i].Dur\|.
	func extractDurations(events []benchmarking.Event) []float64 {
	result := make([]float64, len(events))
	for i, e := range events {
	result[i] = e.Dur
	}
	return result
	}

	// Convert an array of values in microseconds to milliseconds.
	func convertMicrosToMillis(array []float64) []float64 {
	result := make([]float64, len(array))
	for i, item := range array {
	result[i] = item / OneMsecInUsecs
	}
	return result
	}

	// Compute the average of an array of floats.
	func computeAverage(array []float64) float64 {
	result := 0.0
	for _, item := range array {
	result += item
	}
	return result / float64(len(array))
	}

	// Compute the minimum element of \|array\|.
	func computeMin(array []float64) float64 {
	result := math.MaxFloat64
	for _, item := range array {
	if item < result {
	result = item
	}
	}
	return result
	}

	// Compute the maximum element of \|array\|.
	func computeMax(array []float64) float64 {
	result := -math.MaxFloat64
	for _, item := range array {
	if item > result {
	result = item
	}
	}
	return result
	}

	// [x for x in array if x >= threshold]
	func filterByThreshold(array []float64, threshold float64) []float64 {
	result := make([]float64, 0)
	for _, item := range array {
	if item >= threshold {
	result = append(result, item)
	}
	}
	return result
	}

	// Compute the \|targetPercentile\|th percentile of \|array\|.
	func computePercentile(array []float64, targetPercentile int) float64 {
	if len(array) == 0 {
	panic("Cannot compute the percentile of an empty array")
	}
	sort.Float64s(array)
	if targetPercentile == 100 {
	return array[len(array)-1]
	}
	indexAsFloat, fractional := math.Modf((float64(len(array)) - 1.0) * (0.01 * float64(targetPercentile)))
	index := int(indexAsFloat)
	if len(array) == index+1 {
	return array[index]
	}
	return array[index](1-fractional) + array[index+1]fractional
	}

	func averageGap(events []benchmarking.Event, cat1 string, name1 string, cat2 string, name2 string) float64 {
	gapStart := 0.0
	totalTime := 0.0
	numOfGaps := 0.0

	for _, event := range events {
	if event.Cat == cat1 && event.Name == name1 {
	gapStart = event.Start + event.Dur
	} else if event.Cat == cat2 && event.Name == name2 &&
	gapStart != 0.0 {
	if event.Start > gapStart {
	totalTime += (event.Start - gapStart)
	numOfGaps++
	}
	gapStart = 0.0
	}
	}
	return totalTime / numOfGaps
	}

	// Compute the FPS within Scenic for \|trace\|, also writing results to
	// \|results\| if provided.
	func reportScenicFps(model benchmarking.Model, testSuite string, testResultsFile *benchmarking.TestResultsFile) {
	fmt.Printf("=== Scenic FPS ===\n")
	fps, fpsPerTimeWindow := calculateFps(model, "gfx", "FramePresented")
	fmt.Printf("%.4gfps\nfps per one-second window: %v\n", fps, fpsPerTimeWindow)

	testResultsFile.Add(&benchmarking.TestCaseResults{
	Label: "fps",
	TestSuite: testSuite,
	Unit: benchmarking.FramesPerSecond,
	Values: []float64{jsonFloat(fps)},
	})

	testResultsFile.Add(&benchmarking.TestCaseResults{
	Label: "minimum_fps_per_one_second_time_window",
	TestSuite: testSuite,
	Unit: benchmarking.FramesPerSecond,
	Values: []float64{jsonFloat(computeMin(fpsPerTimeWindow))},
	})

	fmt.Printf("\n== Average times ==\n")
	type AverageEvent struct {
	IndentLevel int
	Name string
	Label string
	}

	// List the events we want to include in output. Events are described with:
	// Indentation level in output
	// Event name in trace
	// Event name in output (blank if same as event name in trace)
	averageEvents := []AverageEvent{
	{0, "RenderFrame", ""},
	{1, "ApplyScheduledSessionUpdates", ""},
	{2, "escher::CommandBuffer::Submit", "CommandBuffer::Submit"},
	{1, "UpdateAndDeliverMetrics", ""},
	{1, "EngineRenderer::RenderLayers", ""},
	{0, "Scenic Compositor", "Escher GPU time"},
	}

	gfxStr := "gfx"
	for _, e := range averageEvents {
	events := model.FindEvents(benchmarking.EventsFilter{Cat: &gfxStr, Name: &e.Name})
	durations := convertMicrosToMillis(extractDurations(events))
	avgDuration := jsonFloat(benchmarking.AvgDuration(events) / OneMsecInUsecs)
	if e.Label == "" {
	e.Label = e.Name
	}
	fmt.Printf("%-35s %.4gms\n", strings.Repeat(" ", e.IndentLevel)+e.Label,
	avgDuration)
	if len(durations) == 0 {
	fmt.Fprintf(os.Stderr, "Warning: no values found for %s. Falling back to a zero value.\n", e.Label)
	durations = []float64{0}
	}
	testResultsFile.Add(&benchmarking.TestCaseResults{
	Label: e.Label,
	TestSuite: testSuite,
	Unit: benchmarking.Milliseconds,
	Values: durations,
	})
	}
	renderFrameStr := "RenderFrame"
	scenicCompositorStr := "Scenic Compositor"
	events := model.FindEvents(benchmarking.EventsFilter{Cat: &gfxStr, Name: &renderFrameStr})
	events = append(events, model.FindEvents(benchmarking.EventsFilter{Cat: &gfxStr, Name: &scenicCompositorStr})...)
	sort.Sort(ByStartTime(events))

	fmt.Printf("%-35s %.4gms\n", "unaccounted (mostly gfx driver)",
	jsonFloat(averageGap(events, gfxStr, renderFrameStr, gfxStr, scenicCompositorStr)/OneMsecInUsecs))
	}

	func reportFlutterFpsForInstance(model benchmarking.Model, testSuite string, testResultsFile *benchmarking.TestResultsFile, uiThread benchmarking.Thread, gpuThread benchmarking.Thread, metricNamePrefix string) {
	fmt.Printf("=== Flutter FPS (%s) ===\n", metricNamePrefix)
	flutterStr := "flutter"
	vsyncCallbackStr := "vsync callback"
	vsyncEvents := uiThread.FindEvents(benchmarking.EventsFilter{Cat: &flutterStr, Name: &vsyncCallbackStr})
	fps, fpsPerTimeWindow := calculateFpsForEvents(vsyncEvents)
	fmt.Printf("%.4gfps\nfps per one-second window: %v\n", fps, fpsPerTimeWindow)

	testResultsFile.Add(&benchmarking.TestCaseResults{
	Label: metricNamePrefix + "_fps",
	TestSuite: testSuite,
	Unit: benchmarking.FramesPerSecond,
	Values: []float64{jsonFloat(fps)},
	})

	testResultsFile.Add(&benchmarking.TestCaseResults{
	Label: metricNamePrefix + "_minimum_fps_per_one_second_time_window",
	TestSuite: testSuite,
	Unit: benchmarking.FramesPerSecond,
	Values: []float64{jsonFloat(computeMin(fpsPerTimeWindow))},
	})

	frameStr := "vsync callback"
	frameEvents := uiThread.FindEvents(benchmarking.EventsFilter{Name: &frameStr})

	frameDurations := convertMicrosToMillis(extractDurations(frameEvents))

	drawStr := "GPURasterizer::Draw"
	rasterizerEvents := gpuThread.FindEvents(benchmarking.EventsFilter{Name: &drawStr})
	rasterizerDurations := convertMicrosToMillis(extractDurations(rasterizerEvents))

	type Metric struct {
	Name string
	Values []float64
	}

	metrics := []Metric{
	{"frame_build_times", frameDurations},
	{"frame_rasterizer_times", rasterizerDurations},
	}
	for _, metric := range metrics {
	fullName := metricNamePrefix + "_" + metric.Name
	fmt.Printf("%s: %4g\n", fullName, computeAverage(metric.Values))
	testResultsFile.Add(&benchmarking.TestCaseResults{
	Label: fullName,
	TestSuite: testSuite,
	Unit: benchmarking.Unit(benchmarking.Milliseconds),
	Values: metric.Values,
	})
	}
	}

	func getThreadsWithPrefixAndSuffix(process benchmarking.Process, prefix string, suffix string) []benchmarking.Thread {
	threads := make([]benchmarking.Thread, 0)
	for _, thread := range process.Threads {
	if strings.HasPrefix(thread.Name, prefix) && strings.HasSuffix(thread.Name, suffix) {
	threads = append(threads, thread)
	}
	}
	return threads
	}

	func reportFlutterFps(model benchmarking.Model, testSuite string, testResultsFile *benchmarking.TestResultsFile, flutterAppName string) {
	flutterProcesses := getProcessesWithPrefix(model, "io.flutter.runner")
	for _, flutterProcess := range flutterProcesses {
	gpuThreads := getThreadsWithPrefixAndSuffix(flutterProcess, flutterAppName, ".gpu")
	uiThreads := getThreadsWithPrefixAndSuffix(flutterProcess, flutterAppName, ".ui")
	if len(gpuThreads) != len(uiThreads) {
	panic("Unequal ui threads and gpu threads")
	}

	for i, uiThread := range uiThreads {
	// TODO: We are assuming that threads are in order, instead we should verify
	// that they have the same name % suffix
	gpuThread := gpuThreads[i]
	metricNamePrefix := strings.Split(uiThread.Name, ".")[0]
	reportFlutterFpsForInstance(model, testSuite, testResultsFile, uiThread, gpuThread, metricNamePrefix)
	// TODO: Decide how to handle multiple flutter apps that match the
	// target app name. Just report the first one for now.
	return
	}
	}
	fmt.Printf("Did not find any processes that matched %s\n", flutterAppName)
	}

	func main() {
	// Argument handling.
	verbosePtr := flag.Bool("v", false, "Run with verbose logging")
	flutterAppNamePtr := flag.String("flutter_app_name", "", "Optional: The name of the flutter app to measure fps for.")
	testSuitePtr := flag.String("test_suite_name", "", "Optional: The name of the test suite.")
	outputFilenamePtr := flag.String("benchmarks_out_filename", "", "Optional: A file to output results to.")

	flag.Parse()
	if flag.NArg() == 0 {
	flag.Usage()
	println(" trace_filename: The input trace file.")
	os.Exit(1)
	}

	verbose = *verbosePtr
	inputFilename := flag.Args()[0]
	flutterAppName := *flutterAppNamePtr
	testSuite := *testSuitePtr
	outputFilename := *outputFilenamePtr

	traceFile, err := ioutil.ReadFile(inputFilename)
	check(err)

	// Creating the trace model.
	var model benchmarking.Model
	model, err = benchmarking.ReadTrace(traceFile)
	check(err)

	if len(model.Processes) == 0 {
	panic("No processes found in the model")
	}

	var testResultsFile benchmarking.TestResultsFile
	reportScenicFps(model, testSuite, &testResultsFile)
	reportFlutterFps(model, testSuite, &testResultsFile, flutterAppName)

	if outputFilename != "" {
	outputFile, err := os.Create(outputFilename)
	if err != nil {
	log.Fatalf("failed to create file %s", outputFilename)
	}

	if err := testResultsFile.Encode(outputFile); err != nil {
	log.Fatalf("failed to write results to %s: %v", outputFilename, err)
	}
	if err := outputFile.Close(); err != nil {
	log.Fatalf("failed to close results file %s: %v", outputFilename, err)
	}

	fmt.Printf("\n\nWrote benchmark values to file '%s'.\n", outputFilename)
	}
	}