superlifter design notes and rZync feedback

Martin Pool mbp at samba.org
Fri Jul 19 00:28:55 EST 2002


One more link, about variable-length vs fixed-length encodings:

  http://ntrg.cs.tcd.ie/undergrad/4ba2/presentation/xdrandber.html

(The HTML is a bit broken, view the source.)

Basically they make the somewhat obvious point that variable-length
encodings are much slower to handle than fixed-length.  I don't know
if the difference is so great that lzo encoding could produce a
smaller result with less work.  I wouldn't be surprised either way,
actually.

One way to look at it is this: in the case where you're CPU-bound, not
network-bound, then you'll definitely want to use something like XDR.
In the case where you're completely network-bound, then you probably
want to use gzip -9 or even bzip2, and whether the underlying protocol
is fixed or variable-length probably doesn't matter.  

So perhaps XDR plus compression is a good tradeoff across a wider
domain.  (Or perhaps not.)

-- 
Martin 




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