David Baron :dbaron: Assignee
	Description • 23 years ago

NS_NewAtom currently flattens a string to hash it.  We need a hash function that
takes an nsAString& so we don't need to allocate.  (This seems to be responsible
for about 2000 allocations on startup.)

	David Baron :dbaron: Assignee
	Comment 1 • 23 years ago

FWIW, the allocation sites are:

2033 operator new(unsigned long, const std::nothrow_t&)
		operator new(unsigned long)
		NS_AllocateContiguousHandleWithData ...
		nsSharableString::assign(const nsAString&)
		nsPromiseFlatString::nsPromiseFlatString(const nsAString&)
		PromiseFlatString(const nsAString&)
		GetAtomHashEntry(const nsAString&)
		NS_NewAtom(const nsAString&)
		nsXMLContentSink::SplitXMLName(const nsAString&, nsIAtom**, ...
		nsXMLContentSink::AddAttributes(const nsIParserNode&, ...
		nsXMLContentSink::OpenContainer(const nsIParserNode&)

 648 operator new(unsigned long, const std::nothrow_t&)
		operator new(unsigned long)
		NS_AllocateContiguousHandleWithData ...
		nsSharableString::assign(const nsAString&)
		nsPromiseFlatString::nsPromiseFlatString(const nsAString&)
		PromiseFlatString(const nsAString&)
		GetAtomHashEntry(const nsAString&)
		NS_NewAtom(const nsAString&)
		nsXMLContentSink::SplitXMLName(const nsAString&, nsIAtom**, ...
		nsXMLContentSink::OpenContainer(const nsIParserNode&)

 276 operator new(unsigned long, const std::nothrow_t&)
		operator new(unsigned long)
		NS_AllocateContiguousHandleWithData ...
		nsSharableString::assign(const nsAString&)
		nsPromiseFlatString::nsPromiseFlatString(const nsAString&)
		PromiseFlatString(const nsAString&)
		GetAtomHashEntry(const nsAString&)
		NS_NewAtom(const nsAString&)
		nsXMLContentSink::SplitXMLName(const nsAString&, nsIAtom**, ...
		nsXMLContentSink::AddAttributes(const nsIParserNode&, ...
		nsXMLContentSink::OpenContainer(const nsIParserNode&)

 194 operator new(unsigned long, const std::nothrow_t&)
		operator new(unsigned long)
		NS_AllocateContiguousHandleWithData ...
		nsSharableString::assign(const nsAString&)
		nsPromiseFlatString::nsPromiseFlatString(const nsAString&)
		PromiseFlatString(const nsAString&)
		GetAtomHashEntry(const nsAString&)
		NS_NewAtom(const nsAString&)
		nsXMLContentSink::SplitXMLName(const nsAString&, nsIAtom**, ...
		nsXMLContentSink::AddAttributes(const nsIParserNode&, ...
		nsXMLContentSink::OpenContainer(const nsIParserNode&)

	David Baron :dbaron: Assignee
	Comment 2 • 23 years ago

The above is from http://www.mozilla.org/performance/mallocsites20011031.html

	David Baron :dbaron: Assignee
	Comment 3 • 23 years ago

I never managed to think of a good approach to fixing this, given our hashtable
interfaces.

	Benjamin Smedberg
	Comment 4 • 21 years ago

hrmm, is this still a problem, with the work alecf has been doing with atoms? I
have a hashkey that uses nsAString, but it still has to allocate a copy of the
string buffer, because we're not using sharable strings.

	Alec Flett
	Comment 5 • 21 years ago

well, I'll bet its still a problem - I think that everywhere that I changed to
permanent atoms had flat strings already.. so those call sites are probably
slightly different, but still applicable...

	David Baron :dbaron: Assignee
	Comment 6 • 18 years ago

No longer relevant with our new string code.