The Truth About Your Web App's Performance

The Truth About Your
Web App’s Performance
John Riviello
@JohnRiv
Distinguished Engineer, Comcast Interactive Media
Web Conference at Penn State – June 22, 2015

John Riviello – The Truth Behind Your Web App’s Performance2

Frontend Performance Data
1. What do existing tools provide?
2. What data do you care about?
3. How do you gather that data?
4. What do you do with the data?

1. Existing Tools
2. The Data You Care About
3. Gathering the Data
4. Analyzing the Data

Frontend Performance Data – Existing Tools
WebPagetest.org

http://www.sitespeed.io/

https://github.com/sitespeedio/grunt-sitespeedio

https://github.com/macbre/phantomas
https://github.com/gmetais/grunt-devperf

https://github.com/gmetais/grunt-yellowlabtools

grunt.initConfig({
yellowlabtools: {
production: {
urls: [
'https://xtv.comcast.net'
],
failConditions: [
// The global score is the one calculated by Yellow Lab Tools
'fail if at least one url has a global score < 80/100',
// Every single rule has its own score
'fail if at least one url has a rule score < 50/100',
// You can ignore certain rules
'ignore iframesCount',
// You can check a metric instead of the score by omitting '/100'
'fail if at least one url has a domElementsCount > 2000'
]
}
}
});

Contribute to Open Source:
https://github.com/gmetais/YellowLabTools

"RUM" by Tom B is licensed under CC BY-NC-SA 2.0

Real
User
Monitoring
"yes, that's a rum filled coconut." by Brandon King is licensed under CC BY-NC 2.0 / Color adjusted from original

http://www.appdynamics.com/product/browser-real-user-monitoring/

http://docs.newrelic.com/docs/new-relic-browser/page-load-timing-process

https://ruxit.com/features/real-user-monitoring.html

https://docs.newrelic.com/docs/browser/new-relic-browser/browser-agent-apis/manually-reporting-page-load-timing-data

Illustration from http://www.w3.org/TR/navigation-timing/#processing-model

Frontend Performance Data – The Data You Care About

Frontend Performance Data – The Data You Care About
Example Factors That Impact Performance:
• User authentication state
•“Type” of user
• Number of “items” returned
• Flash SWF dependency

http://mashable.com/2014/01/31/gmail-slow/
“Gmail’s People Widget
appears to be the cause of
the sluggishness, which is,
only affecting Gmail on
the web Google
says…This is noticeable
when users open an email
conversation with a large
number of participants…”

Consider what other unique
factors in your app may
impact performance

Frontend Performance Data – Gathering the Data
Marking Timestamps
Back in the day:
> new Date().getTime();
1399754123456
ECMAScript 5.1:
> Date.now();
1399754123456
Most modern browsers have a better option…

W3C High Resolution Time
•DOMHighResTimeStamp is available via
window.performance.now()
•Provides the time with sub-millisecond accuracy
•Measured relative to the navigationStart attribute
of the PerformanceTiming interface
•Not subject to system clock skew or adjustments
(uses a monotonically increasing clock)

W3C High Resolution Time – Sub-ms Example
> var dateTest = function() {
var start = Date.now(),
area = window.innerWidth*window.innerHeight;
return Date.now() - start;
};
dateTest();
0
> var highResTest = function() {
var start = window.performance.now(),
area = window.innerWidth*window.innerHeight;
return window.performance.now() - start;
};
highResTest();
0.01200000406242907

W3C High Resolution Time – Monotonic Clock
Why do we care?
“Most systems run a daemon which regularly
synchronizes the time. It is common for the clock to be
tweaked a few milliseconds every 15-20 minutes.
At that rate about 1% of 10 second intervals
measured would be inaccurate.”
Source: Tony Gentilcore
http://gent.ilcore.com/2012/06/better-timer-for-javascript.html

https://github.com/Comcast/Surf-N-Perf

User Timing
vs.
Surf-N-Perf
"Hurricane Earl's Waves" by John Riviello is licensed under CC BY-NC-SA 2.0 / Color adjusted from original

Frontend Performance Data – Gathering the Data with Surf-N-Perf
Setting & Getting a Mark
// User Timing API
> window.performance.mark('foo');
> window.performance.getEntriesByName('foo');
[PerformanceMark ]
duration: 0
entryType: "mark"
name: "foo"
startTime: 3323.620999988634
> window.performance.getEntriesByName('foo')[0].startTime;
3323.620999988634
// Surf-N-Perf
> surfnperf.mark('foo');
> surfnperf.getMark('foo');
3323.620999988634

Navigation Timing Mark & User Mark Duration
// User Timing API
> window.performance.mark('foo');
> window.performance.measure('page_load_to_foo', 'loadEventEnd',
'foo');
> window.performance.getEntriesByName('page_load_to_foo');
[PerformanceMeasure ]
duration: 3201.620999988634
entryType: "measure"
name: "page_load_to_foo"
startTime: 122
> window.performance.getEntriesByName('page_load_to_foo')[0].duration;
3201.620999988634
// Surf-N-Perf
> surfnperf.mark('foo');
> surfnperf.duration('loadEventEnd','foo');
3202
> surfnperf.duration('loadEventEnd','foo',{decimalPlaces:3});
3201.621

Event Duration (i.e. 2 User Marks)
// User Timing API
> window.performance.mark('barStart');
> window.performance.mark('barEnd');
> window.performance.measure('barEvent', 'barStart', 'barEnd');
> window.performance.getEntriesByName(’barEvent')[0].duration;
3512.499000004027
// Surf-N-Perf
> surfnperf.eventStart('bar');
> surfnperf.eventEnd('bar');
> surfnperf.eventDuration('bar');
3512
> surfnperf.eventDuration('bar',{decimalPlaces:12});
3512.499000004027

Custom Event Data
// Surf-N-Perf
> surfnperf.eventStart('bar');
// surfnperf.eventEnd(KEY, CUSTOM_DATA_OBJECT);
> surfnperf.eventEnd('bar', {baz:'qux'});
> surfnperf.getEventData('bar', 'baz');
"qux"

Tying It Together with Backbone.fetch()
// Surf-N-Perf
> var collection = new Backbone.Collection();
collection.url = '/get-data/';
surfnperf.eventStart('getData');
collection.fetch({
success: function(collection) {
surfnperf.eventEnd('getData', {status:'success', items: collection.length});
},
error: function() {
surfnperf.eventEnd('getData', {status:'error'});
},
});
> surfnperf.eventDuration('getData', {decimalPlaces:2});
1464.75
> surfnperf.getEventData('getData', 'status');
"success"
> surfnperf.getEventData('getData', 'items');
33

Custom Data (not tied to an event)
// Surf-N-Perf
> surfnperf.setCustom('initialUrl', window.location.pathname);
> surfnperf.getCustom('initialUrl');
"https://xtv.comcast.net/recent"

Common Navigation Timing Measurements
// Surf-N-Perf

> surfnperf.getNetworkTime(); // fetchStart to connectEnd

> surfnperf.getServerTime(); // requestStart to responseEnd

> surfnperf.getNetworkLatency(); // fetchStart to responseEnd

> surfnperf.getProcessingLoadTime(); // responseEnd to loadEventEnd

> surfnperf.getFullRequestLoadTime(); // navigationStart to
loadEventEnd

Frontend Performance Data – Analyzing The Data

Average Response Times
are for
Average Products

Frontend Performance Data – The Future
Time to First Paint
Internet Explorer:
> window.performance.timing.msFirstPaint;
1434341969277
Google Chrome:
> window.chrome.loadTimes();
Object {
commitLoadTime: 1434341655.700179
connectionInfo: "http/1"
finishDocumentLoadTime: 1434341656.208713
finishLoadTime: 1434341656.733739 ...

Time to First Paint
Google Chrome (continued):
firstPaintAfterLoadTime: 1434341657.201959
firstPaintTime: 1434341655.978471
navigationType: "Other"
npnNegotiatedProtocol: "unknown"
requestTime: 1434341655.141803
startLoadTime: 1434341655.570092
wasAlternateProtocolAvailable: false
wasFetchedViaSpdy: false
wasNpnNegotiated: false
}

Time to First Paint
Alternatives:
-window.requestAnimationFrame()
- Load of last non-async resource in <head>
- Custom Metric (First Tweet, Hero Image, etc.)
http://www.stevesouders.com/blog/2015/05/12/hero-image-custom-metrics/

Illustration from http://www.w3.org/TR/resource-timing/#processing-model
window.performance.getEntriesByType("resource")

3rd Party Resource

3rd Party Resource with Timing-Allow-Origin: *

Frontend Performance Data – Recap
• Performance is a feature!
• Measure first—at the 99th percentile
• Leverage W3C Performance APIs
• Log network latency, browser processing time, and
the full webpage request & response
• Log major app-specific events with details
For Further Info & Feedback:
Twitter: @JohnRiv
GitHub: https://github.com/Comcast/Surf-N-Perf
SpeakerRate: http://spkr8.com/t/60261

The Truth About Your Web App's Performance

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