Content

General recommendations
Improvement process

(back to plan)

Useful references

Devoxx France : "Optimiser les performances d’une webapp" (Guillaume EHRET)
https://www.youtube.com/watch?v=9PRPPJFaF_o

General recommendations

no premature optimization
must have a performance objective
should have a workbench (performance test)
"80-20": concentrate of the 20% of the app that is responsible for 80% of the load
one issue often hides other issues
first actions might not show any improvement.
Yet, don’t despair!

Improvement process

run test
measure
if performance objective not reached:
- analyse results, look for:
  - transport issues,
  - then GC issues,
  - then CPU/code optimization
- fix (one at a time!)
- iterate (→ run test)

Performance test

Test data

test with various parameters, especially corner cases

Test harness

properly isolated
test in real-life conditions:
- network (bandwidth and latency)
- server load (does impact response time)
- browser brand and version
- client device type (desktop, mobile phone…) and sizing (CPU, RAM…)

Test scenario

representative of the issue

Monkey testing

Lot’s of random actions (automated)

→ objective is to make sure there is no way the app could crash

(see http://www.redotheweb.com/2014/01/07/completing-the-js-test-stack-introducing-greminsjs.html) → https://github.com/marmelab/gremlins.js

Other topics

http://superherojs.com/#performance

That’s all folks!