mysql scaling questions

[Josh Carroll]

> Does anyone have a theory why syscalls are so expensive in FreeBSD? Here
> are the results of unixbench 4.1 on two machines. First is the machine
> running FreeBSD HEAD (debugging disabled) on a dual-core Athlon 64 (i386
> mode), 2 GHz:

I ran the syscall benchmark from UnixBench on the same hardware (Intel
Q6600 @ 3.2 GHz) for both FreeBSD 7.0-RC1 (amd64) and Knoppix 5.1
(Linux 2.6.9 PREEMPT kernel, i386).

Per the comments in this thread, i386 syscalls should be less
expensive than amd64 syscalls, so the results are interesting:

FreeBSD 7.0-RC1 (amd64):  System Call Overhead
15000.0  1103233.7      735.5
Knoppix Linux 2.6.9 (i686):   System Call Overhead
    15000.0  1108869.7      739.2

I can try to find a Linux live CD with a 2.6.x x86-64 kernel for a
valid apples-to-apples comparison, but thought these results might
provide some parity/insight.

Doesn't look like the syscalls are slower at all on FreeBSD.

Josh