Re: [Maxima-discuss] gcl memory usage

[David S. <d.s...@go...>]

Hi Gunter,


>  - In many mailing list entries GCL_MEM_MULTIPLE describes which
> fraction of the physical RAM is allocated by gcl on startup.
>

Kind of, but this is virtual memory, not actual memory.


>  - In my measurements gcl quickly starts exceeding the limit specified
> as GCL_MEM_MULTIPLE. It seems like GCL other than SBCL is able to
> dynamically increase the amount of memory it uses after having started
> up. Which seems to be a plus for gcl.
>

Yes, I can reproduce this. But this makes me wonder whether that's a bug,
because it's stated that this is an effective upper limit on RAM usage. Or
maybe Maxima somehow goes around LISP and allocates memory directly or from
some third-party library, so it's not affected by GCL's limitation.


>  - Also with the smaller GCL_MEM_MULTIPLE maxima didn't run out of
> memory in the test cases maxima-gcl with the old settings did. My guess
> is that if gcl isn't willing to allocate too much memory on start-up it
> won't fragment its memory pool as fast as with the default settings.
>

It might also be because it starts garbage collection earlier because the
thresholds are relative to the available memory (which you lowered).


> Where did you find documentation about GCL_MEM_MULTIPLE?
>

I only found information on the mailing list via Google, nothing in the
documentation ...

Best regards
David