[Python-Dev] Performance of various marshallers

[Fredrik Lundh]

paul wrote:
> > XML-RPC's relationship to Unicode is ill-defined.  The spec that Dave Winer
> > wrote requires all data to be US-ASCII, so XML-RPC isn't really
> > XML-compliant.  (You'll have to take up issues of standards compliance with
> > Dave.)
> 
> Most XML-RPC implementations support Unicode, Dave Winer
> notwithstanding. Plus, the XML-RPC spec says nothing to indicate that
> XML-RPC documents may not be encoded in either of XML's two built-in
> encodings (even if the data is restricted to ASCII values).

the specification says that XML-RPC uses XML and HTTP.  it
doesn't say anything about a Dave-specific subset of XML or
HTTP...

(like so many other parts of the specification, the "string" type
isn't exactly well-specified. the specification first says that strings
contains ASCII characters, and later that "any characters are
allowed in a string" and that "a string can be used to encode
binary data")

> Yes, an incomplete XML parser could be faster if it ignores Unicode,
> ignores character references, and does not do all of the error checking
> required by the spec.  I'm not sure if this would really improve
> performance anyhow.

well, sgmlop is a bit faster than expat (up to 50%, in some tests).
expat does a bit more error checking.

> xmlrpclib on the other hand, is entirely written in Python. Is there a
> Python XML-RPC implementation that uses no Python code but does
> use a true XML parser?

the _xmlrpclib accelerator (see the xmlrpclib.py source) uses expat,
with a really fast C layer.  judging from Skip's benchmarks, expat is a
bit slower than the py-xmlrpc parser (which is why I asked).

</F>