Firefox has 50% more soft page faults than Chrome running Speedometer 2
Categories
(Core :: Performance, defect)
Tracking
()
Performance Impact | pending-needinfo |
People
(Reporter: alexical, Unassigned, NeedInfo)
References
(Depends on 1 open bug, Blocks 1 open bug)
Details
(Whiteboard: [sp3-react-todomvc])
When running Speedometer 2 on Windows, I see 30k page faults / sec for a release build of Firefox, and only 20k page faults from Chrome. We should diagnose what the underlying difference is here and whether there is an opportunity to improve this situation. (To be clear, almost none of these faults were hard page faults.)
Comment 1•1 year ago
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Running xperf -on ALL_FAULTS -stackwalk PagefaultDemandZero
shows that most of the faults are DemandZeroFaults. This is what I expected.
Comment 2•1 year ago
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Here's a quick profile using xperf -on latency+ALL_FAULTS -stackwalk PagefaultDemandZero
I threw together using that should roughly show where the faults are coming from:
https://share.firefox.dev/3FfEEIs
Comment 3•1 year ago
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It would be good if this profile also included markers for VirtualAlloc/VirtualFree
Comment 4•1 year ago
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xperf -on latency+ALL_FAULTS+VIRT_ALLOC -stackwalk PagefaultDemandZero
gives us events for VirtualAlloc/VirtualFree.
When comparing Firefox vs Chrome in WPA we definitely seem to have a higher rate of VirtualAlloc/VirtualFree when running React-TodoMVC. It also seems like Chrome hits a stable roughly stable "Outstanding commit" better than we do.
Comment 5•1 year ago
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:dthayer, we set the Performance Impact to ?
, could you set it more appropriately please (if needed)?
Updated•1 year ago
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Comment 6•1 year ago
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One possible reason is that our page caches are tiny
https://bugzilla.mozilla.org/show_bug.cgi?id=1805644#c16
Updated•1 year ago
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Updated•1 year ago
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Updated•5 months ago
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Description
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