[e-lang] Side Channels (was: E-on-Common-Lisp now available)

[David Wagner]

Mark Miller writes:
>During the call to f(c1,c2), neither c1 nor c2 can be garbage collected, since 
>they're both reachable. During the call to f(c1,c1), c2 could be garbage 
>collected. This garbage collection
>a) takes time
>b) frees up memory, which potentially allows further allocations to...
>    i)  ... take less time, or
>    ii) ... to succeed rather than fail.

Ahh!  Great.  This makes sense now.  Thanks for the very concrete
example.

As you've written elsewhere, it may be possible to at least partially
deal with memory allocation failures, by terminating the entire vat when
the first memory allocation failure occurs.  But the variability in running
time seems much harder to address.  So, this answers my question.

Thanks again.