Open Bug 1303751 Opened 8 years ago Updated 2 years ago

Large etherpad documents become unusable in Firefox


(Core :: DOM: Core & HTML, defect, P3)





(Reporter: jrmuizel, Unassigned)



(Keywords: perf)

This document is painful to edit in Firefox. It works fine in Chrome.

Here's a profile:

Much of the time is spent re-spellchecking the entire document. (bug 1303749)
Depends on: 1303749
Does the profile point to a Mac-specific issue (I am probably just reading it improperly but:

FWIW the editing seems pretty painless on Windows in Aurora.
Flags: needinfo?(mstange)
It's true, the profile shows a lot of Mac event loop overhead in the parent process. It would be nice to find out why for example setWindowsNeedUpdate is called so frequently; it seems to be called for every IPC message that the parent process receives from the content process.

But the real problem in that profile is happening in the content process, and that's almost exclusively bug 1303749.

There's also a bit of slow JS execution in there, for example in this part:,%22start%22%3A357951,%22end%22%3A359149%7D%5D . 
Though 5.5% of JS execution is in CodeGeneratorShared::generateCompactTrackedOptimizationsMap, which is maybe only called when you're profiling.
Flags: needinfo?(mstange)
Priority: -- → P3
Keywords: perf
Depends on: 1354641
Depends on: 1355595
Depends on: 1355600
No longer depends on: 1355600
Component: DOM → DOM: Core & HTML
Severity: normal → S3
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