1537779 - Improve column breakpoint UI performance

Status: RESOLVED FIXED

(DevTools :: Debugger, defect, P1)

Description

[Jason Laster [:jlast]]

I noticed while profiling debugger.html that getColumnBreakpoints takes awhile for debugger.html profile

The reason looks like getSelectedLocation, which calls isOriginalId.

STR:

1. go to localhost:8000
2. select debugger.js
3. add some breakpoints
4. reload...

Comment 1

[Jason Laster [:jlast]]

Another hot spot, which comes from jryans' app is filterByUniqLocation profile. I assume this must happen if you get a lot of breakpoint positions back.

Comment 2

[Jason Laster [:jlast]]

Another hot spot in debugger.html is findEmptyLines profile,

• this also looks related to getSelectedLocation.
• the split takes awhile

Comment 3

[Jason Laster [:jlast]]

After looking into this a bit, i'm seeing a couple of things:

1. using a synchronous getOriginalLocation will have a nice impact (1.8sec --> 450ms) old --> new

2. memoizing URL parsing in source-map saves 200ms (475ms --> 287ms) . old --> new (PR)

3. sending the packet of 80K locations to and from the worker is slow...
4. supporting 80K locations in other UI elements is slow...
5. the UI feels much snappier after the first two fixes

Comment 4

[Jason Laster [:jlast]]

Attachment: Bug 1537779 - Improve column breakpoint UI performance. r=loganfsmyth

Comment 5

[Jason Laster [:jlast]]

Attachment: Bug 1537779 - Improve column breakpoint UI performance. r=loganfsmyth

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ff20472890a1
Improve column breakpoint UI performance. r=loganfsmyth

Comment 7

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/mozilla-central/rev/ff20472890a1

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0ec8134b1b62
Improve column breakpoint UI performance. r=loganfsmyth

Comment 9

[Oana Pop-Rus]

https://hg.mozilla.org/mozilla-central/rev/0ec8134b1b62

Comment 10

[Julian Descottes [:jdescottes]]

When connected to an older server, the call to getBreakableLines fails:

"Action loadSourceText had an exception:" 
  "Protocol error (unrecognizedPacketType): 
   Actor server1.conn2.child9/source23 does not recognize the packet type getBreakableLines"

What can be the impact of this for a debugging session, should we address it?

Edit: discussing with Yulia, one of the possible regressions linked to this is that all lines appear greyed out as if we couldn't set breakpoints on them. Anything else?