Open Bug 1667157 Opened 8 months ago Updated 2 months ago

FirstPaint performance regression with Fission in browsertime


(Core :: DOM: Content Processes, defect, P2)




Fission Milestone M8


(Reporter: jesup, Assigned: jesup)


(Whiteboard: fission-perf)

We see a regression in firstvisualchange/FNBP/etc metrics with browsertime with fission turned on on 2017 Acer windows laptop (reference laptop). This is likely related to the process-switch to a new process that happens during the load.

See browsertime results here:


Summary: FirstPaint performance regression with Fission in browsertime on low-end HW → FirstPaint performance regression with Fission in browsertime


Severity: -- → S3
Fission Milestone: --- → M7
Priority: -- → P2
Whiteboard: [fission] → fission-perf

From jesup

It'd be helpful to look at profiles of fission vs e10s loads, and see if there's any useful things we can do to minimize the process-switch overhead (moving initializations of things, lazifying things, etc). More generally, we see small perf regressions avg. 3-6%) on load in tp6 raptor, and I see very close to a wash on visual metrics on high-end HW. And FVC and FP on the larger high-end test weren't much regressed, note. On the 2-core it was significant (25-35%)

Randell will re-do these measurements for both high-end and low-end to get the latest numbers, as the old ones are 5 months old.

Flags: needinfo?(rjesup)
Assignee: nobody → rjesup
Flags: needinfo?(rjesup)

Only visual metrics should be blocking M7.

Fission Milestone: M7 → M8
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