Temporary AtomicStrings are causing churn in the AtomicString hash

[Eric Seidel (no email)]

Temporary AtomicStrings are causing churn in the AtomicString hash

mike belshe mentioned seeing some problems related to atomicstring hashtable thrashing in Chromium tonight in #webkit.  I wanted to file this bug (and attach a possible patch) before I forgot.  Mike may already be working on a solution.

[Eric Seidel (no email)]

Created attachment 28883 [details]
Attempt at catching AtomicString table thrash (untested)

 WebCore/platform/text/AtomicString.cpp |   54 ++++++++++++++++++++++----------
 1 files changed, 37 insertions(+), 17 deletions(-)

[Mike Belshe]

Two places I saw this in common code:
   1) CSSFontSelector.cpp
   2) ResourceRequestBase.cpp

I filed bug 24485 for the CSSFontSelector issue.

I'm still working on the second.  The patch you have proposed won't catch this code (I think) from ResourceRequestBase.cpp:
    return (m_httpHeaderFields.contains("If-Match") ||
            m_httpHeaderFields.contains("If-Modified-Since") ||
            m_httpHeaderFields.contains("If-None-Match") ||
            m_httpHeaderFields.contains("If-Range") ||
            m_httpHeaderFields.contains("If-Unmodified-Since"));

[Mike Belshe]

(In reply to comment #2)
> I filed bug 24485 for the CSSFontSelector issue.

Whoops - I meant bug 24785