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

[Julian Elischer]

Achim Patzner wrote:

>
> Am 06.01.2005 um 22:26 schrieb Julian Elischer:
>
>>> then i wiill try it with HT enabled  and hope for the best.
>>
>> The biggest problem is that it will slow your system down..
>
>
> I'd not agree on this for every available CPU; I just finished some 
> extensive test using XEON 3,6 GHz and there is no noticeable 
> difference between running the Intel SE7520BD2 with two processors 
> enabled (and HT disabled) or one processor and HT. Ok, maybe the board 
> isn't that good (it was a severe mistake ordering it as the second NIC 
> (Intel Yukon) is wasted space)... 


this is true but the original author specified he's using the 2.8GHz CPUs.

>
>
>> one of them should be doing Floating Point ops while the other is
>> doing integer.. (they share the integer ALU I believe).
>
>
> Not anymore; the latest XEONs finally have enough brains in their skull.
>
>> 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.
>
>
> Especially doing a "make buildworld" was faster with HT turned on 
> while ubench was suffering quite a bit.
>
>
> Achim
>
> PS: I would by those machines again - this time with an SE7520AF 
> mainboards.
> PPS: Of course they are doing much better runnig an amd64 kernel.
>
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