From: Testbed Support for GridPP member institutes [[log in to unmask]] on behalf of Rob Fay [[log in to unmask]]
Sent: 09 March 2012 15:46
To: [log in to unmask]
> Consequently, we intend to initially run with 16 jobs per node and see how that
> performs in real life.
How much memory and disk have you got? A job slot isn't just about the CPU.
What's always put me off hyperthreading is that while there's clearly a performance
benefit, the cost of the extra RAM etc. that you need (twice as much if you use all
the HT units) makes that extra performance very expensive as compared with just
buying more real CPUs.
The only time we've ever used it was when we borrowed some local cluster nodes
that had 4Gb of memory per core, so still having 2Gb per HT.