Re: mysql scaling questions

Josh Carroll wrote:
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
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Per later discussion you will also need to either comment out the syscalls that are (might be) being cached by glibc to artificially inflate its reported rate, or verify that it is not doing so.

Kris
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