[webkit-changes] [WebKit/WebKit] 930124: [JSC] Adjust IC initial countdown

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 930124da7f2e3ba36f66a5a702a57ca7ce0eb231
      https://github.com/WebKit/WebKit/commit/930124da7f2e3ba36f66a5a702a57ca7ce0eb231
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2023-02-08 (Wed, 08 Feb 2023)

  Changed paths:
    M Source/JavaScriptCore/bytecode/StructureStubInfo.h
    M Source/JavaScriptCore/runtime/OptionsList.h

  Log Message:
  -----------
  [JSC] Adjust IC initial countdown
https://bugs.webkit.org/show_bug.cgi?id=251905
rdar://105165183

Reviewed by Keith Miller and Mark Lam.

This patch adjusts IC's countdown number (which is used before starting generating IC).
We accidentally found that the current number "8" is not optimal in terms of performance.
By exhaustive parameter searching, we found that "4" for initial count is better.
It improves Speedometer2.1 by 0.54% and JetStream2.1 by 0.66%.

* Source/JavaScriptCore/bytecode/StructureStubInfo.h:
(JSC::StructureStubInfo::StructureStubInfo):
* Source/JavaScriptCore/runtime/OptionsList.h:

Canonical link: https://commits.webkit.org/260016@main