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On Mon, Nov 15, 2004 at 10:53:35PM +0000, Ian Stokes-Rees wrote: > In a loaded cluster, HT means the job will, roughly speaking, have half as > much memory and take twice as long as on the same node with HT turned > off. This can have very serious consequences for queue time limits for > long running jobs. A dual 1 gig RAM, 3 GHz CPUs WN should, really, be > "advertised" as: > > * 512 meg 3 GHz node x 2 (HT off) > * 256 meg 1.5 MHz node x 4 (HT on) First off, 1.5GHz would be a better number to adviertise :-) But more importantly you should NEVER advertise a HT enable CPU as anything else then 1 CPU. Because it ISN'T 2 CPU's. If you turn HT on you should use that small increase in capacity internally and not advertise it, i.e. for system processes that are running and possibly for use of threaded libraries. After all it is HyperTHREAD not HyperCPU!! Anything else is just plain stupid. And yes, the worst case scenario is what you should advertise. -- Ake Sandgren, HPC2N, Umea University, S-90187 Umea, Sweden Internet: [log in to unmask] Phone: +46 90 7866134 Fax: +46 90 7866126 Mobile: +46 70 7716134 WWW: http://www.hpc2n.umu.se