[webkit-dev] Enabling the HTML5 tree builder soon

[Stephanie Lewis]

I measure it as a 1% win on the PLT.

-- Stephanie

On Jul 26, 2010, at 12:36 PM, Stephanie Lewis wrote:

> I can do this.
> 
> -- Stephanie Lewis
> 
> On Jul 26, 2010, at 5:57 AM, Adam Barth wrote:
> 
>> Would someone from Apple be willing to run the patch below though the
>> PLT?  We're doing well on our parsing benchmark (4% speedup), but the
>> PLT might have a different mix of HTML.
>> 
>> Thanks,
>> Adam
>> 
>> 
>> diff --git a/WebCore/html/HTMLTreeBuilder.cpp b/WebCore/html/HTMLTreeBuilder.cpp
>> index 7a9c295..5b89c37 100644
>> --- a/WebCore/html/HTMLTreeBuilder.cpp
>> +++ b/WebCore/html/HTMLTreeBuilder.cpp
>> @@ -327,7 +327,7 @@ HTMLTreeBuilder::HTMLTreeBuilder(HTMLTokenizer*
>> tokenizer, HTMLDocument* documen
>>    , m_originalInsertionMode(InitialMode)
>>    , m_secondaryInsertionMode(InitialMode)
>>    , m_tokenizer(tokenizer)
>> -    , m_legacyTreeBuilder(shouldUseLegacyTreeBuilder(document) ? new
>> LegacyHTMLTreeBuilder(document, reportErrors) : 0)
>> +    , m_legacyTreeBuilder(0)
>>    , m_lastScriptElementStartLine(uninitializedLineNumberValue)
>>    , m_scriptToProcessStartLine(uninitializedLineNumberValue)
>>    , m_fragmentScriptingPermission(FragmentScriptingAllowed)
>> 
>> 
>> On Thu, Jul 22, 2010 at 3:30 AM, Adam Barth <abarth at webkit.org> wrote:
>>> We're getting close to enabling the HTML5 tree builder on trunk.  Once
>>> we do that, we'll have the core of the HTML5 parsing algorithm turned
>>> on, including SVG-in-HTML.  There are still a bunch of details left to
>>> finish (such as fragment parsing, MathML entities, and better error
>>> reporting), but this marks a significant milestone for this work.
>>> 
>>> The tree builder is markedly more complicated than the tokenizer, and
>>> I'm sure we're going to have some bad regressions.  I'd like to ask
>>> your patience and your help to spot and triage these regressions.
>>> We've gotten about as much mileage as we can out of the HTML5lib test
>>> suite and the LayoutTests.  The next step for is to see how the
>>> algorithm works in the real world.
>>> 
>>> There are about 84 tests that will require new expectations, mostly
>>> due to invisible differences in render tree dumps (e.g., one more or
>>> fewer 0x0 render text).  In about half the cases, we've manually
>>> verified that our new results agree with the Firefox nightly builds,
>>> which is great from a compliance and interoperability point of view.
>>> The other half involve things like the exact text for the <isindex>,
>>> which we've chosen to match the spec exactly, or the <keygen> element,
>>> which needs some shadow DOM love to hide its implementation details
>>> from web content.
>>> 
>>> As for performance, last time we ran our parser benchmark, the new
>>> tree builder was 1% faster than the old tree builder.  There's still a
>>> bunch of low-hanging performance work we can do, such as atomizing
>>> strings and inlining functions.  If you're interested in performance,
>>> let me or Eric know and we can point you in the right direction.
>>> 
>>> I don't have an exact timeline for when we're going to throw the
>>> switch, but sometime in the next few days.  If you'd like us to hold
>>> off for any reason, please let Eric or me know.
>>> 
>>> Adam
>>> 
>>> P.S., you can follow along by CCing yourself on the master bug,
>>> <https://bugs.webkit.org/show_bug.cgi?id=41123>, or by looking at our
>>> LayoutTest failure triage spreadsheet,
>>> <https://spreadsheets.google.com/ccc?key=0AlC4tS7Ao1fIdEo0SFdLaVpiclBHMVNQcHlTenV5TEE&hl=en>.
>>> 
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