Re: [Maxima-discuss] gcl memory usage

[Gunter K. <gu...@pe...>]

On 23.04.2018 17:59, David Scherfgen via Maxima-discuss wrote:
> Maybe you're right, Robert.
> 
> But I still think that Gunter may have misinterpreted GCL_MEM_MULTIPLE.

I hope I didn't - even if I am not completely sure:

 - In many mailing list entries GCL_MEM_MULTIPLE describes which
fraction of the physical RAM is allocated by gcl on startup.
 - 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.
 - 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.
 - Camm told that starting with GCL_MEM_MULTIPLE gcl's heap will grow to
3/4 of the physical memory installed Don't know if this amount of memory
will get lower if GCL_MEM_MULTIPLE is decreased, though: Didn't find any
documentation for this feature.

As a side node the testbench ran impressively fast with the more
aggressive gc settings. Normally I am used that gcl needs what feels
like hours even for simple tasks.

Where did you find documentation about GCL_MEM_MULTIPLE?

Kind regards,

 Gunter.