[Larceny-users] Heaps in err5rs: giant heaps, errors loading, extra slow compile with -stopcopy

[Felix Klock]

On May 16, 2008, at 7:08 PM, William D Clinger wrote:

> Some possibilities for the poor load time:
>
>    bug in compiler (such as using eq? hash tables,
>        which are much slower with the stop-and-copy
>        collector than with the generational)
>
>    bug in Larceny's stop-and-copy garbage collector
>        (unlikely)
>
>    stop-and-copy collection really is that much
>        slower when Twobit is compiling a large
>        program

I believe the stopcopy collector for Intel native Larceny on the trunk  
of the development tree suffers from at least one severe performance  
bug that we identified and I fixed on a development branch back in  
February.  That bug may be causing Ryan's load time problems.

See changeset:5429, whose log message has links to some relevant  
Tickets describing the problem.

http://larceny.ccs.neu.edu/larceny-trac/changeset/5429

I have been meaning to fix Tickets #119 and #335 for Intel native on  
the trunk since February; I have had higher priority concerns for a  
while, but now would be a good time for me to do that task.

(My understanding of Larceny's collectors has matured considerably  
between when I first opened Ticket #119 two years ago and when I  
identified #119 as a severe performance bug during some benchmarking 3  
months ago, so I think I can come up with an appropriate short-term  
fix for the trunk over the weekend.  Merging changeset:5429 into the  
trunk could very well be the best short-term fix.)

-Felix