Multiple CPUs

[Charles Swiger]

On Dec 13, 2005, at 2:12 PM, Robert Fitzpatrick wrote:
> I guess this means my new server is only using one of my CPUs?
>
> esmtp# grep CPU /var/log/dmesg.today
> CPU: Intel(R) Xeon(TM) CPU 2.40GHz (2399.33-MHz 686-class CPU)
>   Hyperthreading: 2 logical CPUs
> cpu0: <ACPI CPU (2 Cx states)> on acpi0
>
> Can someone point me to the best doc for enabling use of both CPUs on
> the FreeBSD 5.4 server? I assume the kernel needs built with options.

Note that if you've only got one physical HTT-capable CPU, running in  
single-processor mode is likely to give better performance than  
running SMP just to enable the hyperthreaded virtual CPU.  If you've  
got a dual-CPU box and need to run SMP for that anyway, then using  
HTT seems to sometimes help and sometimes reduce performance.

-- 
-Chuck