Dual Xeon 2.8 with HT - How is the support in FreeBSD 5.3

[Julian Elischer]

Spirre wrote:

>Ok, nice do you run 5.3?
>then i wiill try it with HT enabled  and hope for the best. because i  heard
>it was some problems with the logical cpus the system makes.
>

The biggest problem is that it will slow your system down..
HTT should only be used in soem very specific workloads.
In particular yuo need to really have both processors
working on the same data (they share a cache) and
one of them shuld be doing Floating Point ops while the other is
doing integer.. (they share the integer ALU I believe).
There are apps that do ok, but for example compiles get slowed down
as the virtual CPUs flush each other's cache entries out and contest for 
the ALU.


HTT != 2 CPUS

>
>Thanks for fast reply and good answer..
>
>Regards
>Christian S
>
>----- Original Message ----- 
>From: "Bryan" <bvest at rhondasworld.com>
>To: "Spirre" <spirre at rareshell.com>
>Cc: <freebsd-smp at freebsd.org>
>Sent: Thursday, January 06, 2005 5:54 PM
>Subject: Re: Dual Xeon 2.8 with HT - How is the support in FreeBSD 5.3
>
>
>  
>
>>We have 6 dual Xeons with HT on that are part of a spam filtering
>>network running sendmaiul, they are all running FreeBSD. We have not had
>>one crash out of these systems which process 3 million emails per day.
>>We were running RedHat and they would constantly crash. After the switch
>>to FreeBSD we have been beoynd imnpressed with the stability.
>>
>>
>>Bryan
>>
>>Spirre wrote:
>>    
>>
>>>Hi,
>>>I have a server with dual xeon and HT support that i wonder is if
>>>      
>>>
>freebsd has good support for HT? im going to run apache and mysql. Is it any
>preformance issues with it enabled or disabled in BIOS?
>  
>
>>>Ps. Dont want a server that crashes every second week.
>>>
>>>
>>>Regards
>>>Christian S
>>>_______________________________________________
>>>freebsd-smp at freebsd.org mailing list
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>>>
>>>
>>>      
>>>
>>_______________________________________________
>>freebsd-smp at freebsd.org mailing list
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>>
>>    
>>
>
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>