1378735 - [meta] We should lazy load all the things as this will have the biggest effect on a tool’s startup time

Status: NEW

(DevTools :: General, enhancement, P5)

Description

[Mike Ratcliffe [:miker] [:mratcliffe] [:mikeratcliffe]]

Filter on EdgarMallory

Comment 1

[Patrick Brosset <:pbro>]

Not getting to that one this quarter. Still a good idea, but needs to become actionable, and is probably going to be a meta bug.

Comment 2

[Alexandre Poirot [:ochameau]]

It is quite actionable by looking at the profiler output. It is related to bug 1378734!

On the child process, you can see that highlighters actor takes a significant time in the overall setup of actors.

Here is the profiler, focused on highlighters.js load:
  https://perfht.ml/2extfI1
(clear the search box to see how big it is compared to everything else).

http://searchfox.org/mozilla-central/source/devtools/server/actors/highlighters.js
Which is mainly composed of css-grid:
  http://searchfox.org/mozilla-central/source/devtools/server/actors/highlighters/css-grid.js

How do I find this?
* Make a profile
  * open a clean firefox
  * install perf-html if not already done on perf-html.io
  * open data:text/html,foo (to avoid unecessary noise in the profile)
  * start profiling (ctrl+shift+1)
  * toggle the inspector via the key shortcut
  * get the profile (ctrl+shift+2) (and stop profiling via ctrl+shift+1)
* Open the profile
* select the content process
  Sometime you have more than one, here, the one I care is the second one.
  You can figure out which one is what by looking at JS frames in the call tree.
* Filter "JS Only" in the call tree
* expand the tree and look at what takes the more time, expand over and over.

Comment 4

[Patrick Brosset <:pbro>]

All dependencies are solved now. Do we plan to add more to this bug or should we close it?