Re: analyzing postgresql performance for dbt-2

I've done a better controlled series of tests where I restore the
database before each test and have grabbed sar and oprofile data:

http://developer.osdl.org/markw/dbt2-pgsql/176/
    - load of 100 warehouses
    - metric 1234.52

http://developer.osdl.org/markw/dbt2-pgsql/177/
    - load of 120 warehouses
    - metric 1259.43

http://developer.osdl.org/markw/dbt2-pgsql/178/
    - load of 140 warehouses
    - metric 1244.33

For the most part our primary metric, and the vmstat and sar output look
fairly close for each run.  Here are a couple of things that I've found
to be considerably different from run 176 to 178:

- oprofile says postgresql calls to SearchCatCache increased ~ 20%

- readprofile says there are 50% more calls in the linux kernel to
  do_signaction (in kernel/signal.c)

Would these two things offer any insight to what might be throttling the
throughput?

Thanks,
Mark