Google I/O 2010 Notes
Talk: Measure in milliseconds redux: Meet Speed Tracer
Notes by: Armando Padilla
Disclaimer!!!
• These are only notes that I took during the talk. I take no
ownership of the material presented during the talk.
Again these are solely my notes I took during the talk. If
I made a mistake in what’s presented here that’s just my
mistake due to my poor note taking skillz.
With legal out of the way…Let’s Continue…
Measure in milliseconds redux:
Meet Speed Tracer
Abstract from Talk:
It turns out that web apps can be slow for all sorts of opaque and unintuitive reasons.
Don't be fooled into thinking that bloated, slow JavaScript is the only culprit. This session
introduces you to Speed Tracer, a new GWT tool that can tell you exactly where time is
going within the browser.
Tools Used & Featured: Speed Tracer.
Why performance matters
• Affects users impression of the
application.
– Users are very sensitive to delays.
– User perception of quality changes as the
performance is degradatted.
The Magic Number!
• 100ms
– Threshold in which a user remains satisfied
with the application.
– Above 100ms user leaves or becomes
dissatisfied with application.
So where’s are the problems?
• We don’t measure.
– Measuring our application is infrequently
done.
• Blame it on the browser.
– Browsers use special tweaks to speed up
loading of JS, CSS, etc. Not all browsers
apply them the same… So we run into
problems.
Where are the bottlenecks?
• Network.
• Amount of data transferred.
• How is the browser behaving?
Solution!
Speed Tracer.
• Informs what the browser is doing and times your
application.
• Ability to share data with other developers by
saving it.
• Allows us to zoom into specified request and
receive detailed information about the request
down to what the Browser is doing.
• http://code.google.com/webtoolkit/speedtracer/
Speed Tracer NEW Feature!
• Latest release informs you of the line of
code that is causing the issue.
• Clicking on the warning will open your
code and show you the line on your code.
• Only available when using it with GWT.
Additional Notes
• App Engine Integration
– Displays information on what a request is
doing at the server level.
Google & CI
• In use at Google.
• Speed Tracer fully integrated.
• New commits trigger a speed audit using
Speed Tracer.