recursion in XML parser

[David Megginson]

xml writes:

 > I can see that on a Pentium 300 you wouldn't notice the function
 > call overhead/stack framing for recursive processing.  Thanks.  My
 > own experience using the Java XML frameworks is that they are slow.

Hmm -- they are somewhat slower than Expat, but that's because they're
running tight code loops in a virtual machine.  Still, when I was
testing AElfred on a 166MHZ Pentium NT box back in late 1997, it could
parse about 1MB/second with a good VM and a JIT, and the other good
XML parsers are comparable in speed.

Granted, Expat (with memory-mapped I/O) is about 10 times as fast as
the faster Java-based XML parser, but that's a very misleading figure:
in fact, the actual parsing usually occupies only a small amount of
the time required for XML processing -- most of the time is usually
taken up by your code that actually does something with the XML.

Let's assume, then, that XML parsing occupies 10% of your
application's overhead.  Even if you could build a parser that is
1000% faster, you'd still gain only 9% in actual execution speed.


All the best,


David

-- 
David Megginson                 david at megginson.com
           http://www.megginson.com/

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