felix <xxxxxx@call-with-current-continuation.org> writes:
> As the document correctly points out, calls from Scheme to C can be
> a lot more efficient, if it is known that callbacks into Scheme do
> not occur.  This applies to Chicken (for example), where all sorts
> of weird things happen in such a case. So, here I'm down on my
> knees, *begging* for separate forms of Scheme->C calls that forbid
> callbacks. This also simplifies the case when threads are involved
> (if thread-switches can only occur in Scheme code). Note that
> Scheme->C calls outnumber Scheme->C->Scheme ones usually by a large
> amount.

Could you give details about the sorts of optimizations this
information enables?