Problems with GC malloc


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From Robert Penny <rob@network.ucsd.edu>
Date Mon, 4 Jun 2001 13:49:42 -0700 (PDT)
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Hi,

I'm using ng-spice-rework14-pre2 to perform a transient analysis on 
a design with 3076 MOSFETs and 4673 capacitors.  Analysis on a smaller
design with 880 MOSFETs and 1756 capacitors completes successfully in
about 6 minutes.  On the larger design the simulation dies after 20
minutes with the error:

     Too many heap sections: Increase MAXHINCR or MAX_HEAP_SECTS
     Aborted

The error is actually coming from gc malloc not from ngspice but I'm
wondering if it is a symptom of something that ngspice is doing.

I've tried compiling gc malloc with -DLARGE_CONFIG but spice is still
running out of memory... or rather gc malloc is having problems.  At its
maximum spice is still only taking 7.5% of physical memory ( 7.5% of 750
MB ) when it dies.

I seem to remember there being some good reason I was working with the
GC_MALLOC version of ngspice rather than the non- GC_MALLOC version,
though I'm going to try recompiling with this turned off to see if I can
get my analysis to complete.

I'm running on a linux system with glibc 2.1.2.

Does anyone have any insight into the problem, or at least experience with
analysis of designs of comparable size in ngspice?

Thanks in advance,

-Rob Penny (rob@ucsd.edu)


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