Closed Bug 1548048 Opened 7 years ago Closed 3 years ago

Investigate why we didn't see any improvement in Win 7 startup from better XUL.dll readahead

Categories

(Toolkit :: Startup and Profile System, task, P3)

Product:
Toolkit
Component:
Startup and Profile System
Type:
task

Tracking

()

Status:
RESOLVED WONTFIX

People

(Reporter: alexical, Unassigned)

References

Details

(Keywords: perf, Whiteboard: [fxperf:p3])

We saw solid wins from bug 1538279 on Windows 10, but no observable difference for Windows 7. Windows 7 falls back to explicitly paging in parts of XUL.dll rather than using PrefetchVirtualMemory, which could potentially explain things, but we also are seeing strange behavior in bug 1546498 that may have something to do with this. We should investigate what's going on here to ensure we're not missing out on an opportunity in Windows 7.

Type: defect → task
Priority: -- → P3

Tentatively picking p3 for this one but if bug 1546498 turned up something that might alter cost/reward here it might well want to be p2/p5 instead.

Whiteboard: [fxperf] → [fxperf:p3]

I don't think bug 1546498 is relevant because it is not specific to Windows 7 at all. If we backout bug 1546498 and disable PrefetchMemory on all platforms, Windows 10 will crash in exactly the same way. Even a minimal test program will also crash. See bug 1546498 comment 14 about the reason for the crash. It is wrong to assume that we can read everywhere in mapped executable images.

Severity: normal → S3

We unsupported win7 so it seems unlikely that reviving this old bug will get us actionable work.

Status: NEW → RESOLVED
Closed: 3 years ago
Resolution: --- → WONTFIX
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