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|
<!DOCTYPE html>
<!--
Copyright 2017 The Chromium Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->
<link rel="import" href="/tracing/extras/chrome/event_finder_utils.html">
<link rel="import" href="/tracing/metrics/metric_registry.html">
<link rel="import" href="/tracing/value/histogram.html">
<script>
'use strict';
// The |androidStartupMetric| produces metrics that (unless noted otherwise)
// start counting at the earliest moment the Chrome code on Android is
// executed. A few histograms are produced with the names as described below:
//
// * messageloop_start_time - Time till the message loop of the browser main
// starts processing posted tasks (after having loaded the Profile)
//
// * experimental_navigation_start_time - This roughly corresponds to the time
// the initial navigation network request is sent on the UI thread
//
// * experimental_network_request_start_time - Time until the first network
// request starts in the netlog. The actual bytes will be sent to the network
// slightly later: after disk cache responds. This metric can be used even for
// netowrk loads that are served from the disk cache. Currently relies on
// NetworkService running in the browser process.
//
// * navigation_commit_time - This is when the renderer has received the first
// part of the response from the network after all redirects and started
// loading the page. Recorded when the confirmation is received on the browser
// UI thread.
//
// * first_contentful_paint_time - Time to the first 'contentful' paint of the
// page loaded at startup
//
// * process_create_to_app_start_time - Time from process creation until the
// application starts. The end time of this event will be the same as the
// start time of messageloop_start_time.
//
// The metric also supports multiple browser restarts, in this case multiple
// samples would be added to the histograms above.
tr.exportTo('tr.metrics.sh', function() {
const MESSAGE_LOOP_EVENT_NAME = 'Startup.BrowserMessageLoopStartTime';
const NAVIGATION_EVENT_NAME = 'Navigation StartToCommit';
const FIRST_CONTENTFUL_PAINT_EVENT_NAME = 'firstContentfulPaint';
const APPLICATION_START_EVENT_NAME =
'Startup.LoadTime.ProcessCreateToApplicationStart';
const REQUEST_ALIVE = 'REQUEST_ALIVE';
function isGetRequest(event) {
if (event.args &&
event.args.params &&
event.args.params.method == 'GET') {
return true;
}
return false;
}
function findRequestEventAfterNavigation(networkEvents, range) {
let requestStart = range.max;
let requestEvent = null;
for (const event of networkEvents) {
if (isGetRequest(event)) {
for (const subSlice of event.subSlices) {
if (subSlice.title === REQUEST_ALIVE &&
range.min <= subSlice.start && subSlice.start < requestStart) {
requestStart = subSlice.start;
requestEvent = subSlice;
}
}
}
}
return requestEvent;
}
function androidStartupMetric(histograms, model) {
// Walk the browser slices, extract timestamps for the browser start,
// message loop start.
let messageLoopStartEvents = [];
let applicationStartEvents = [];
let navigationPairs = [];
function organizeBrowserEventByTitle(event, process) {
if (event.title === MESSAGE_LOOP_EVENT_NAME) {
messageLoopStartEvents.push(event);
} else if (event.title === APPLICATION_START_EVENT_NAME) {
applicationStartEvents.push(event);
} else if (event.title === NAVIGATION_EVENT_NAME) {
const networkEvents =
tr.e.chrome.EventFinderUtils.getNetworkEventsInRange(process,
event.range);
const requestEvent = findRequestEventAfterNavigation(
networkEvents, event.range);
navigationPairs.push({
'nav': event,
'req': requestEvent,
});
}
}
const chromeHelper =
model.getOrCreateHelper(tr.model.helpers.ChromeModelHelper);
if (!chromeHelper) return;
for (const helper of chromeHelper.browserHelpers) {
for (const ev of helper.mainThread.asyncSliceGroup.childEvents()) {
organizeBrowserEventByTitle(ev, helper.process);
}
}
// Walk the renderer slices and extract the 'first contentful paint'
// histogram samples.
let firstContentfulPaintEvents = [];
const rendererHelpers = chromeHelper.rendererHelpers;
const pids = Object.keys(rendererHelpers);
for (const rendererHelper of Object.values(chromeHelper.rendererHelpers)) {
if (!rendererHelper.mainThread) continue;
for (const ev of rendererHelper.mainThread.sliceGroup.childEvents()) {
if (ev.title === FIRST_CONTENTFUL_PAINT_EVENT_NAME) {
firstContentfulPaintEvents.push(ev);
// There are usually several 'First Contentful Paint' events recorded
// for each page load. Take only the first one per renderer.
break;
}
}
}
// Fallback to scanning all processes if important events are not found.
let totalBrowserStarts = messageLoopStartEvents.length;
let totalFcpEvents = firstContentfulPaintEvents.length;
if (totalBrowserStarts !== totalFcpEvents ||
totalBrowserStarts !== navigationPairs.length ||
totalBrowserStarts !== applicationStartEvents.length ||
totalBrowserStarts === 0) {
messageLoopStartEvents.length = 0;
navigationPairs.length = 0;
firstContentfulPaintEvents.length = 0;
applicationStartEvents.length = 0;
// Sometimes either the browser process or the renderer process does not
// have the proper name attached. This often happens when both chrome
// trace and systrace are merged. Other multi-process trickery, like
// Perfetto, may also cause this.
for (const proc of Object.values(model.processes)) {
for (const ev of proc.getDescendantEvents()) {
organizeBrowserEventByTitle(ev, proc);
}
for (const ev of proc.getDescendantEvents()) {
if (ev.title === FIRST_CONTENTFUL_PAINT_EVENT_NAME) {
firstContentfulPaintEvents.push(ev);
break;
}
}
}
totalBrowserStarts = messageLoopStartEvents.length;
totalFcpEvents = firstContentfulPaintEvents.length;
}
// Sort the events by start time.
function orderEvents(event1, event2) {
return event1.start - event2.start;
}
messageLoopStartEvents.sort(orderEvents);
applicationStartEvents.sort(orderEvents);
firstContentfulPaintEvents.sort(orderEvents);
function orderPairs(pair1, pair2) {
return pair1['nav'].start - pair2['nav'].start;
}
navigationPairs.sort(orderPairs);
// Remove spurious navigation events. Only one 'Navigation StartToCommit'
// event should remain for each browser session. When multiple events are
// encountered for a browsing session, remove all except the first one. The
// first navigation event looked more realistic for the story
// maps_pwa:with_http_cache (http://crbug.com/1307774).
let filteredNavigationPairs = [];
let filteredRequestsFollowingNavigation = [];
let navigation_index = 0;
let messageloop_index = 0;
do {
// Set |browserStart| as the upper limit for the set of navigations to
// select from.
let browserStart = Number.POSITIVE_INFINITY;
if (messageloop_index < messageLoopStartEvents.length) {
browserStart = messageLoopStartEvents[messageloop_index].start;
}
// From navigation events preceding |browserStart| take the first one,
// skip others.
let navigationFound = false;
for (; navigation_index < navigationPairs.length; navigation_index++) {
// Each request event has to be at the same index as its corresponding
// navigation event. Take either both of them or none.
const navPair = navigationPairs[navigation_index];
const navEvent = navPair['nav'];
const requestEvent = navPair['req'];
if (navEvent.start >= browserStart) {
break;
}
if (!navigationFound) {
if (messageloop_index === 0) {
throw new Error('Found a navigation event before browser start');
}
filteredNavigationPairs.push(navPair);
navigationFound = true;
}
}
// Run the last iteration with |browserStart| as positive infinity.
} while (messageloop_index++ <= messageLoopStartEvents.length);
navigationPairs = filteredNavigationPairs;
// Verify the number of FCP events to avoid pairing them to browser starts
// incorrectly. Absence of navigation events does not cause FCP events to be
// dropped.
if (totalFcpEvents < totalBrowserStarts) {
throw new Error('Found fewer FCP events (' + totalFcpEvents +
') than browser starts (' + totalBrowserStarts + ')');
}
// Group the relevant events with the corresponding browser starts and emit
// the metrics.
const messageLoopStartHistogram = histograms.createHistogram(
'messageloop_start_time',
tr.b.Unit.byName.timeDurationInMs_smallerIsBetter, []);
const navigationStartHistogram = histograms.createHistogram(
'experimental_navigation_start_time',
tr.b.Unit.byName.timeDurationInMs_smallerIsBetter, []);
const requestStartHistogram = histograms.createHistogram(
'experimental_network_request_start_time',
tr.b.Unit.byName.timeDurationInMs_smallerIsBetter, []);
const navigationCommitHistogram = histograms.createHistogram(
'navigation_commit_time',
tr.b.Unit.byName.timeDurationInMs_smallerIsBetter, []);
const firstContentfulPaintHistogram = histograms.createHistogram(
'first_contentful_paint_time',
tr.b.Unit.byName.timeDurationInMs_smallerIsBetter, []);
const applicationStartHistogram = histograms.createHistogram(
'process_create_to_app_start_time',
tr.b.Unit.byName.timeDurationInMs_smallerIsBetter, []);
// The earliest 2 browser starts are skipped to reduce measurement noise.
// See http://crbug.com/891797.
let navIndex = 0;
let fcpIndex = 0;
for (let loopStartIndex = 0; loopStartIndex < totalBrowserStarts;) {
const loopStartEvent = messageLoopStartEvents[loopStartIndex];
// There should be a corresponding application start event for each
// message loop start event.
const applicationStartEvent = applicationStartEvents[loopStartIndex];
if (fcpIndex === totalFcpEvents) {
break;
}
// Skip all events that appear before the next browser start.
const navPair = navIndex < navigationPairs.length ?
navigationPairs[navIndex] : null;
const navEvent = navPair ? navPair['nav'] : null;
if (navEvent && navEvent.start < loopStartEvent.start) {
navIndex++;
continue;
}
const fcpEvent = firstContentfulPaintEvents[fcpIndex];
if (fcpEvent.start < loopStartEvent.start) {
fcpIndex++;
continue;
}
// The pair of matching events is found.
loopStartIndex++;
// Skip the two initial FCP events and (potentially missing) browser
// starts.
if (fcpIndex < 2) {
continue;
}
// Record the histograms.
messageLoopStartHistogram.addSample(loopStartEvent.duration,
{events: new tr.v.d.RelatedEventSet([loopStartEvent])});
if (navEvent) {
navigationStartHistogram.addSample(
navEvent.start - loopStartEvent.start,
{events: new tr.v.d.RelatedEventSet([loopStartEvent, navEvent])});
navigationCommitHistogram.addSample(
navEvent.end - loopStartEvent.start,
{events: new tr.v.d.RelatedEventSet([loopStartEvent, navEvent])});
const requestEvent = navPair['req'];
if (!requestEvent) {
throw new Error('No network request after navigation');
}
requestStartHistogram.addSample(
requestEvent.start - loopStartEvent.start,
{events: new tr.v.d.RelatedEventSet([navEvent, requestEvent])});
}
firstContentfulPaintHistogram.addSample(
fcpEvent.end - loopStartEvent.start,
{events: new tr.v.d.RelatedEventSet([loopStartEvent, fcpEvent])});
if (applicationStartEvent) {
applicationStartHistogram.addSample(applicationStartEvent.duration,
{events: new tr.v.d.RelatedEventSet([applicationStartEvent])});
}
}
}
tr.metrics.MetricRegistry.register(androidStartupMetric);
return {
androidStartupMetric,
};
});
</script>
|
