[gambit-list] Speed on XML-parsing
Christian Jaeger
christian at pflanze.mine.nu
Sat Aug 16 10:46:47 EDT 2008
Mikael More wrote:
> Marc,
>
> just to ensure I got your point. You say that one could create a string-port
> more than 20 times faster than Gambit's built-in string ports. I'm
> interested in the reason - is this because:
>
> a) If one writes one in scheme code, Gambit may perform function inlining?
> b) You presume that the string-port implementation one writes does not need
> to be thread-safe, within the context of Gambit's threading system, as is
> Gambit's built in string port?
>
It's both because of read-char requiring a real cross-module Scheme call
(it is not being inlined) but also because it is implemented thread
safe, i.e. using a (Gambit) mutex internally.
See my demo at http://scheme.mine.nu/gambit/experimental/read-char/
(which just a rehash of what Brad Lucier showed on the mailing list in
february 2007 in the "fast csv parser" thread) where I showed that to
someone on IRC.
You really want to clone
http://scheme.mine.nu/gambit/experimental/read-char/.git and look at the
history since there you find the benchmark results.
> Any more reasons?
>
> Also, what further reasons do you see as to why a SSAX-SXML XML to SXML
> deserialization that takes 3 seconds in Java takes 50 seconds in Gambit?
You could take a look at the Java code. Probably it isn't reading from
the input in single chars with mutex locking for each of them.
Christian.
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