marshal.dumps quadratic growth and marshal.dump not allowing file-like objects

[bkustel at gmail.com]

I'm stuck on a problem where I want to use marshal for serialization
(yes, yes, I know (c)Pickle is normally recommended here). I favor
marshal for speed for the types of data I use.

However it seems that marshal.dumps() for large objects has a
quadratic performance issue which I'm assuming is that it grows its
memory buffer in constant increments. This causes a nasty slowdown for
marshaling large objects. I thought I would get around this by passing
a cStringIO.StringIO object to marshal.dump() instead but I quickly
learned this is not supported (only true file objects are supported).

Any ideas about how to get around the marshal quadratic issue? Any
hope for a fix for that on the horizon? Thanks for any information.