cvs commit: src/sys/amd64/amd64 mp_machdep.c src/sys/i386/i386 mp_machdep.c

[Maxim Sobolev]

Bruce Evans wrote:
> Off is a good default since hyperthreading seems to be a pessimization
> in most casts.

Well, actually it all depends on workload and scheduling. I believe ULE 
is expected to improve things quite a bit in scheduling department. 
However, even with ol'good SCHED_BSD we measured noticeable performance 
increase (15-25%) in CPU intensive real-world tasks  with HTT enabled on 
2-way SMP Xeon system. It was in 2004, both CPUs and schedules should 
have been improved since that time.

-Maxim