Kris Kennaway wrote:

> In the meantime I ran sysbench with postgresql 8.2.  Same NetBSD configs 
> as before (except I built my own kernel with the sched_m2 patches since 
> I needed to tweak the sysv ipc parameters).
> 
>   http://people.freebsd.org/~kris/scaling/netbsd-pgsql.png
> 
> postgresql is much more scalable than mysql on this workload and doesn't 
> have silly scaling bottlenecks inside the application (cf the tail of 
> the FreeBSD curve for mysql which is where pthread mutex contention 
> kicked in).

Here are some more graphs.

This one is on the 4 CPU P3 500 MHz and shows postgresql 8.2.  FreeBSD 
is about 15-20% higher throughput.

   http://people.freebsd.org/~kris/scaling/4cpu-pgsql.png

This one shows mysql on the same system

   http://people.freebsd.org/~kris/scaling/4cpu-mysql.png

In that test NetBSD does outperform FreeBSD but only by 3-4% (in 
particular I am not seeing the ~10% difference that Andrew observes on 
his 4*p3 700MHz).  Given the age of the hardware and the fact that I am 
not seeing it on other workloads or on modern hardware it might just be 
due to a small scheduling difference on this configuration.

Kris