From: Erich F. <ef...@hp...> - 2003-04-21 22:26:11
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On Saturday 19 April 2003 17:20, Martin J. Bligh wrote: > I think the case when the busy node rebalance is broken (as far as I'm > concerned) is when the load is low. If I have 4 tasks on one node > (1 per cpu) and none on the other, that's just fine by me. That's what > I said I was going to fix last night. However, I realised that sucks > for other people ... we need a better metric here. Indeed... CPUs in one node are typically on a common FSB. This means that the bandwidth to memory inside a node is limited and the CPUs share it. It makes a lot of difference to have one bandwidth eater one one node which gets the full stream performance or have two of them, each getting only half of the performance. > Erich, I presume you want more perfect balancing across nodes for mem > bandwidth concerns? Ie on a 4 node, 2 cpu per node system (which is wha= t > I thought yours was), you don't want 2/2/0/0 tasks for each node, you > really, really want 1/1/1/1? Or is 2/2/0/0 just as good? The TX7 has normally 4 CPUs per node. My particular configuration has 2. I absolutely prefer 1/1/1/1 :-) Regards, Erich |