Hyperthreading slowdown

[Mikulas Patocka]

Hi

I installed FreeBSD 4.9RC1 on P4 3GHz with hyperthreading and I see
drastic slowdown when kernel with hyperthreading is booted. For example
program compilation took this time:

hyperthreading kernel,  make -j 1 --- 1:09
hyperthreading kernel,  make -j 2 --- 0:42
singlethreading kernel, make -j 1 --- 0:45
singlethreading kernel, make -j 2 --- 0:41

Compilation does very few system calls so when I compile with only one
process (-j 1), it should be as fast as with singlethreading kernel. Do
you have any idea why is it so slow?

Mikulas