Memory utilization (linux v. openbsd)

[nazgul at jsbsystems.com]

Hi all,

I have an app that runs on multiple boxes.  On my slackware box, running 
Python 2.5.1, top shows this:

Mem:   1002736k total,   453268k used,   549468k free,    31392k buffers
Swap:  2097136k total,        0k used,  2097136k free,   136876k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 2741 dnm       16   0  267m 261m 2676 S 99.3 26.7  14:54.62 python

The same app running on OpenBSD 4.1 (but on Python 2.5P3 from ports) 
yields this (actually, I have 2 copies running on a dualcore box):

Memory: Real: 1130M/1989M act/tot  Free: 792K  Swap: 337M/2048M used/tot

  PID USERNAME PRI NICE  SIZE   RES STATE    WAIT     TIME    CPU 
COMMAND
12380 dnm       64    0  926M  436M run/0    -       22:22 73.58% 
python2.5
22956 dnm       64    0  933M  695M onproc/0 -       22:46 68.55% 
python2.5

RES was has over 800M earlier in the job.

My problem is that the two process under OpenBSD are going to fail with 
a MemoryError becaause the size just keeps getting larger and larger.  
ulimit -d is 1G for each process.

Any idea why the memory utilization is so much higher under OpenBSD?

What I also find interesting is that the OpenBSD box seems to grind to a 
halt (that's probably due to swapping since there's 500M of swap space 
in use).  Those processes should both be over 90% since they are CPU 
bound, and they are that way at the start of the run.  Gradually, the 
system % creeps up as does idle, but there's no reason for them to be 
idle.  It's a CPU bound process.  (While I'm typing this top is showing 
cpu rats of 63% and 41% for the two jobs).

TIA,
nazgul