Re: cell heap usage in 1.8 vs 1.6

[Ludovic Courtès]

Hi,

Kevin Ryde <address@hidden> writes:

> I'm having trouble in my charting program with the amount of heap space
> allocated for cells in 1.8.  It ends up allocating more and more heap
> (as reported by gc-stats 'cell-heap-segments and confirmed by
> mallinfo()), apparently without bound.  I've got between 150k and 200k
> objects according to gc-live-object-stats, which should be about 5Mb of
> cells, but the heap keeps growing to as much as 60Mb.

OK, I *think* I hit it with a long-running program with HEAD (this has
become visible now that the thing has been running for more than 72
hours...).

> (define (total-heap)
>   (apply + (map (lambda (elem)
>                   (abs (- (cdr elem) (car elem))))
>                 (assoc-ref (gc-stats) 'cell-heap-segments))))
>
> (define (count-alive)
>   (apply + (map cdr (gc-live-object-stats))))

Note that `count-alive' returns a number of objects, while `total-heap'
(which really is "total *cell* heap") returns a number of bytes, right?
Thus, the result of `count-alive' should be multiplied by 8 (regular
cells) or 16 (double cells).

Nevertheless, even when multiplying `count-alive' by 16, I get a
`total-heap' an order of magnitude larger, which seems to confirm your
hypothesis (that more heap is being allocated despite the availability
of free cells).

To be continued...

Ludo'.