Re: Comparing Guile's GC with BDW-GC

[Neil Jerram]

On 05/11/2008, Ludovic Courtès <address@hidden> wrote:
> Hello!
>
>  I finally [0] conducted experiments to compare Guile's GC with my port
>  of Guile to the Boehm-Demers-Weiser GC (BDW-GC).  The code for that port
>  is not currently available on-line but I'd be happy to push it somewhere
>  (would Guile's repo at Savannah be a good fit?).

I don't see why not...

Just a couple of quick comments on the results...

>  The Results
>  -----------
>
>  There are two benchmarks where BDW-GC is both faster and less
>  memory-hungry than Guile's GC (marked with an `!'):

>  For `string', I expect it to be partly due to the fact that under
>  unmodified Guile it's libc's malloc that's exercised more than the GC
>  itself (since stringbuf contents are allocated with `malloc ()').

How is that different in BDW-GC Guile?

>
>  In most other cases, BDW-GC yields smaller execution times at the
>  expense of increased heap usage.

It's always possible to trade execution for heap, isn't it?  For
example, I presume we could configure current Guile so as to gc less?

In these results, it looks like Guile is quicker for a given heap size
- or smaller for a given execution time.

>
>  I think the question of whether BDW-GC is "worth it" becomes more of an
>  engineering matter if performance is neither problematic not
>  exceptional.

Do you just mean having to maintain the code?

Regards,
      Neil