FreeBSD5.3-RC1 MySQL Performance

Hello,

i found some time to make some performance tests with mysql under
FreeBSD5.3-RC1. Hardware is a HP DL360 with 2x2,8GHz Xeon CPU´s, 2GB,
deactivated HTT and u160/10krpm scsi drive. For reference values i took a
RedHat Fedora with native threads (NPTL) on 2.6 kernel and the same
hardware. for benchmarks i used super-smack with the default smack files.
the MySQL backend was MyISAM.

with both setups the mysql was always under high load which seemed to me for
a good sign to recognize expressive values on thread execution and mysql
performance without loosing to much time in i/o.

the benchmark is executing 1000 sql-select queries*10 concurrent clients on
a 90k row table with a random not really high cacheable where-statement on
the index:
----
15985 queries per second
(pthreads without process scope threads, sched_4bsd and preemption)
6139   queries per second
(pthreads with process scope threads, sched_4bsd and preemption)
10779 queries per second
(linuxthreads, sched_4bsd and preemption)
fedora result:
11900 queries per second
----
same test (same parameters) but with a update query first and then a select
query on the same key i realized worse values for freebsd:
----
2027.52 queries per second
(pthreads without process scope threads, sched_4bsd and preemption)
1146.66 queries per second
(pthreads with process scope threads, sched_4bsd and preemption)
3040.78 queries per second
(linuxthreads, sched_4bsd and preemption)
fedora result:
3920.21 queries per second
----

i checked if i could tune up the update query procedure with writing on a
ramdisk, but this wasnt a highly profit.
if i could use the mixture of linuxthreads on updates and pthreads on select
queries without the use of proc scope it would
be a good answer to linux, but fedora wasnt reachable in its update
operation..


here the relevant used mysql values in this test:
----
query_cache_size=64000000
key_buffer_size=1024M
table_cache=128
thread_cache_size=128
max_connections=1000
----

maybe someone got some hints for improvement of this situation...

regards,
jesk