More kernel performance tests on FreeBSD 10.0-CURRENT

Hi all,

As a followup to my previous post about the performance of FreeBSD 10.0
kernels compiled with different compilers (clang and gcc), I did another
series of tests, now on a more modern machine (Core i5-based).  I also
tested the performance with different compiler optimization settings.

The attached text file[1] contains more information about these tests,
performance data, and my conclusions.  Any errors and omissions are also
my fault, so if you notice them, please let me know.

The executive summary: GENERIC kernels compiled with clang 3.2 are again
a little faster than those compiled with gcc 4.2.1.  For gcc, compiling
with -O2 also gives a slightly faster kernel than with -O1, but for
clang there is no measurable difference between those flags.

Again, many thanks to Gavin Atkinson for providing the required
hardware.

-Dimitry

[1]: Also available at:
<http://www.andric.com/freebsd/perftest/perftest-kernel-2012-09-21a.txt>