Bug 176473 - pdfjs performance regresses if OSR exit uses arrayModeFromStructure() for observing ArrayModes.
Summary: pdfjs performance regresses if OSR exit uses arrayModeFromStructure() for obs...
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: JavaScriptCore (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-09-06 11:59 PDT by Mark Lam
Modified: 2017-09-06 12:00 PDT (History)
6 users (show)

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Description Mark Lam 2017-09-06 11:59:08 PDT 
While working on https://bugs.webkit.org/show_bug.cgi?id=175144, we saw a 18-20% regression in pdfjs.  This regression due to my changing the new OSR exit code to use arrayModeFromStructure() to compute the observed ArrayMode.  Logging shows that the observed cell is a TypeUint8 array.  Hence, arrayModeFromStructure() should have returned a more accurate ArrayMode profile, which should be better for performance.  Instead, it resulted in a performance regression.