SCO 5.0.4 & SMP on Oracle 7.3.3: bad performances

I experiment strange results on SCO SMP server:

If running only one cpu with heavy load cpu sql queries in parallel, the CPU load is 100% as

expected, and real time is n=single query * number of parallel queries, also as expected.

When running two CPUs, with the same queries, each CPU load is 50%, giving a 50% total CPU load and the total time is the same,though it should have been something like 50% less.

When running non-oracle concurrent programs with heavy CPU load, the expected 100% load for both CPU is achieved, as expected, so the problem seems not be a sco SMP problem.

The query is:
select count(a.ename)
from emp a,emp,emp,emp,emp,emp;

Note that there is *no* disk IO
and cpu_count=2

Any idea why adding CPU count does not improve performances ?

Thank you,

Francois Desarmenien Received on Thu Aug 13 1998 - 11:48:02 CDT