1590003 - DAMP Perf regression in inspector cold open test (+9%)

Status: RESOLVED FIXED

(DevTools :: Inspector: Compatibility, task, P2)

Description

[Julian Descottes [:jdescottes]]

Performance regression from Bug 1587690.

The changes that landed in Bug 1587690 introduced a 25% increase in the total number of characters loaded for the inspector, and a 9% slowdown on first open.

In particular the reducer should probably introduce lazy loading, and stop instantiating MDNCompatibility on load.

Comment 1

[Julian Descottes [:jdescottes]]

Hi Daisuke, do you want to take a look at this performance regression? It would be nice to uplift the fix, since we just missed the merge.
Thanks!

Comment 2

[Daisuke Akatsuka (:daisuke)]

Thank you very much for letting me know, Julian!
Let me take a look!

Comment 3

[Daisuke Akatsuka (:daisuke)]

Attachment: Bug 1590003: Lazily load the compatibility lib and the dataset. r?jdescottes

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8d16e7a647e8
Lazily load the compatibility lib and the dataset. r=jdescottes

Comment 5

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/8d16e7a647e8

Comment 6

[Daisuke Akatsuka (:daisuke)]

Comment on attachment 9103433 [details]
Bug 1590003: Lazily load the compatibility lib and the dataset. r?jdescottes

Beta/Release Uplift Approval Request

• User impact if declined: DevTools' initial booting will take time a bit.
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): This patch changed only a way to load the data diagnosis. And this affects only DevTools.
• String changes made/needed:

Comment 7

[Julian Descottes [:jdescottes]]

Attachment: image.png

Thanks for the fix Daisuke!

Just wanted to mention that we can already see on the performance dashboard that the performance regression has been fixed on inspector cold open:
https://firefox-dev.tools/performance-dashboard/tools/inspector.html?days=14&filterstddev=true&ignoreFlags=true

Comment 8

[Pascal Chevrel:pascalc]

Comment on attachment 9103433 [details]
Bug 1590003: Lazily load the compatibility lib and the dataset. r?jdescottes

Low risk perf fix in devtools confirmed by our perf automation, uplift approved for 71 beta 5, thanks!

Comment 9

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/releases/mozilla-beta/rev/dabd951da527