Skip to content
Switch branches/tags
Go to file
Cannot retrieve contributors at this time

Modern Performance in the Year of the Dog - Jem Young @jemyoung

  • How to balance perfect engineering with perfect design?
  • Balance User Experience with Developer Experience
  • Internet 3x faster than it was a few years ago, are websites 300% faster?

Engineering is about trade-offs. Good engineering is about making good trade-offs. – Jacques Favreau

What makes up performance?

  • most people would say measurement. TTR 3s we good, etc.
  • performance tips and their trade-offs

thing // trade-off

What is the best site on the internet?

  • Craigslist is great
    • Fast, everything is on front page
    • HTML, CSS, minimal JS

use only html & css // limits features

Developer Performance

  • One of the most neglected topics when we talk about performance
  • When’s the last time you wrote a web server in C?

What is developer performance?

  • performance === productive
  • Can I walk into a codebase and solve a problem quickly?


  • team_snake_case vs teamCamelCase
  • be consistent // developer freedom

Let’s build an app

  • OMG, dogs! v1.0
  • css/ js/ html/
  • scripting time is the slowest part
  • Does it make you more productive?
  • developer productivity // page weight
  • choose what makes your team productive

Application Performance

  • OMG, dogs! v1.1
  • click a button -> get a dog
  • Time it, takes over 1000ms from button click to loading the next dog image

Network Performance

  • fetch lol

  • Promise.all, wait for all the images to load

  • Promise.race, first one that comes back gets returned

    • it throws away the other requests
    • but the idea still holds
    • What sort of data structure should we use?
    • Buffer
    • Jem you work at Netflix? RXJS?
      • no
    • Bluebird?
      • Pugsly is concerned about our use of libraries
      • “Infinite collection” -> generator
        • while(true) { ._.
  • OMG dogs! v2.0

    • pretty fast
    • we just thought about the problem differently

maximize all connections // resource consumption

  • We don’t want to forget about mobile users, they don’t have unlimited data plans

    • we can’t just blindly apply performance tips, we should think very carefully about what we’re doing
  • how do we know?

    • measuring performance
    • OMG, dogs! v2.2
    • measure FPS, TTR, PWT, … // uncertainty
      • let’s say it’s causing frames to drop, how do we know?

Server Performance

  • transfer protocols
    • http/1.1 - 2.1s
    • http/2 - 901ms
    • using http/2 can increase page speed // need to use SSL
      • what’s the problem with using SSL?
      • computing cert can be expensive
      • is it worth the server cost? yes, internet privacy is important, but it’s still important to weigh the tradeoffs
  • compression
    • instead of sending every bit, we send in weird language that explains what that file is
    • gzip vs brotli
      • brotli is 3x slower on the server
    • static compression?
    • use brotli to compress static files // server overhead

How to balance perfect engineering with perfect design?

design // engineering you can’t - you do the best you can