bizarre performance issues in 6.2 release

[Cheffo]

Hi all,

garcol at postino.it wrote:
> See  kern/83406: [smp] em/bge drivers: severe performance loss under SMP
> 
> 
> sysctl machdep.cpu_idle_hlt=0
> (sysctl machdep.hyperthreading_allowed=1)

What actually do this ? (sysctl machdep.cpu_idle_hlt=0)

 From this PR (kern/83406) it seems that if you want full performance
you need machdep.cpu_idle_hlt=0 and machdep.hyperthreading_allowed=0
or machdep.cpu_idle_hlt=1 and machdep.hyperthreading_allowed=1, and 
others combination drop performance ..

Am I getting it right ?
And if yes why by default HT is disable, but machdep.cpu_idle_hlt is 
enabled ?

I'm little confused :)

> 
> Regards
> Alessandro
> 
>> Try disabling hyperthreading on the 6.2-server. In some cases you get
>> a moderate performance-increase, in most cases this setting is
>> counter-productive.
>>
>> regards
>> Claus
> _______________________________________________
> freebsd-performance at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-performance
> To unsubscribe, send any mail to "freebsd-performance-unsubscribe at freebsd.org"
> 
> 


-- 
Best Wishes,
Stefan Lambrev
ICQ# 24134177