Hi,
Ake wrote:
>>1. Hyper-threading should be turned off everywhere.
>
> I don't agree on that. We have it turned on but don't advertise it so
> that jobs usually beleives that it's not there leaving the "second" cpu
> for system processes.
And here is a DeveloperWorks report which shows the speed-up (or
slow-down) for various operations with or without HT:
http://www-128.ibm.com/developerworks/linux/library/l-htl/
It comes out generally in favour of HT, but, as I said, I was surprised
not to find anyone here at Supercomputing who will vouch for HT for
scientific computing clusters.
What advantage do you get by saying there is a second processor which
you only use for maintenance operataions? Couldn't you just run a
additional process on the one real processor?
>>3. Intel Itaniums currently have PCI-X support, which gives them some
>>improved device access, however
>>
>>4. The next generation of AMD 64-bit processors will support PCI-X
>
> Do you really mean PCI-X? Most all server boards have had PCI-X support
> since at least a year ago. All our Opterons have it.
Sorry, I think that should have been PCI Express, which, I think, is not
yet in AMD 64-bit processors (yet:
http://www.theregister.co.uk/2004/10/19/amd_pci-e_launch/ ) and which I
understand is primarily for visualisation (faster graphics card
connections than AGP).
Cheers,
Ian.
--
Ian Stokes-Rees [log in to unmask]
Particle Physics, Oxford http://www-pnp.physics.ox.ac.uk/~stokes
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