Re: Fork-based version of pgbench

Now that I've fixed the silly mistake in the fork-based version of
pgbench,
http://archives.postgresql.org/pgsql-patches/2005-12/msg00017.php
I'm seeing it consistently outperform the CVS-tip version by about 5%.
I get about 700 tps versus 670 tps; meanwhile "top" reports that idle
CPU percentage drops from around 15% to around 5%.  So I'm thinking
it may be worthwhile to fix the portability issues (ie, provide a
thread-based variant for Windows) and make it the standard version.
It's not so much that I want to inflate the measurements, as that
leaving 10% of the CPU on the table reduces pgbench's usefulness as
a way of stress-testing the backend.

The test case I'm looking at is on a dual Xeon, EM64T, hyperthreading
enabled (hence, 4 logical CPUs), running Fedora Core 4.  Database
parameters are stock except these changes to minimize I/O:fsync = offshared_buffers = 50000checkpoint_segments = 30
Database is initialized with "pgbench -i -s 10 bench" and then tested
with "pgbench -c 10 -t 3000 bench"; I usually do three runs and take
the median to have a trustworthy number.

It'd be interesting to find out if other people can get similar results
on other platforms.
        regards, tom lane