[MIT-Scheme-devel] bookkeeping memory allocated per primitive

[Taylor R Campbell]

Attached is a patch that records the value of Free on entry to each
primitive, so that Primitive_GC can add the amount the primitive has
bumped Free so far to the number of words currently being requested.
This way, primitives performing multiple separate allocations each
with its own GC check won't go into loops.  The change is simpler than
I thought it would be when I wrote the long-winded message last week.

I performed some not particularly scientific tests which indicated
that this patch made compiling the whole system take about .5% more
time.  I think that is an acceptable cost for making the system more
robust, but perhaps you may disagree.  (Summary of the performance
comparison attached.)

Any objections to committing this?

fix-prim-gc.patch
Description: Binary data

bench.txt
Description: Text document