Bug 180929

Summary: REGRESSION (r225789): 35% regression in cold time-to-first-load by enabling service workers
Product: WebKit Reporter: Tim Horton <thorton>
Component: WebKit2Assignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: aestes, ap, beidson, cdumez, ggaren, rniwa, simon.fraser, webkit-bug-importer, wenson_hsieh, youennf
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=180976
Attachments:
Description Flags
test app none

Tim Horton
Reported 2017-12-18 03:01:08 PST
Created attachment 329646 [details] test app Steps to Reproduce: 1. Run the attached test app. 2. Revert r225789. 3. Run the attached test app again. Expected: Relatively similar results. Actual: GlobalCold Navigation Time goes up by 35% (for me, ~330ms -> ~450ms) This measures the time it takes to load about:blank in the first WKWebView in a given UI Process. Other metrics (subsequent views, etc.) don't similarly go up, so this has to be a fixed one-time cost of some sort. I haven't looked at traces yet.
Attachments
test app (32.04 KB, application/zip)
2017-12-18 03:01 PST, Tim Horton 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Tim Horton
Comment 1 2017-12-18 03:03:12 PST
> Other metrics (subsequent views, etc.) don't similarly go up, so this has to be a fixed one-time cost of some sort. Actually, not true, they just go up by much less (5-10%)
Radar WebKit Bug Importer
Comment 2 2017-12-18 11:32:35 PST
<rdar://problem/36111525>
Chris Dumez
Comment 3 2017-12-18 14:25:14 PST
Could be due to the fact that we have to wait for the SW database to be read from disk before we can serve the first load.
Chris Dumez
Comment 4 2017-12-18 14:35:39 PST
(In reply to Chris Dumez from comment #3) > Could be due to the fact that we have to wait for the SW database to be read > from disk before we can serve the first load. (and reading the SW database also requires the StorageProcess to be launched.
youenn fablet
Comment 5 2017-12-18 14:39:38 PST
We can probably easily optimize the case of non HTTP/HTTPS main pages. We know about:blank will never get intercepted.
youenn fablet
Comment 6 2017-12-19 09:24:17 PST
(In reply to youenn fablet from comment #5) > We can probably easily optimize the case of non HTTP/HTTPS main pages. > We know about:blank will never get intercepted. Filed https://bugs.webkit.org/show_bug.cgi?id=180976 for that purpose.
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