Closed Bug 1635569 Opened 3 months ago Closed 3 months ago

Properly set flags on dlls opened and mapped for prefetching

Categories

(Toolkit :: Startup and Profile System, enhancement)

enhancement

Tracking

()

RESOLVED FIXED
mozilla78
Tracking Status
firefox78 --- fixed

People

(Reporter: dthayer, Assigned: dthayer)

References

(Blocks 1 open bug)

Details

(Whiteboard: [fxperf])

Attachments

(1 file)

This is not documented, but there's strong reason to believe that our flags aren't quite right WRT prefetching images. See https://chromium-review.googlesource.com/c/chromium/src/+/1534983/17/base/files/memory_mapped_file_win.cc#23 - committed by a Microsoft engineer.

Blocks: 1627071

This is plausibly affecting the performance of our reads against xul.dll. I started looking through chrome's prefetching code after I noticed (comparing procmon logs of firefox vs chrome startup) chrome.dll prefetching showed reads of 1MiB in length, whereas we just read single pages. Also possibly unrelated. Need to test.

Pushed by dothayer@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/875ebbd9a1c9
Set execute flags when prefetching images r=aklotz
Status: NEW → RESOLVED
Closed: 3 months ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla78
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