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Old 2019-11-03, 23:44   #1
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"Ed Hall"
Dec 2009
Adirondack Mtns

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Default Msieve LA with openmpi in the Current Age

Back in the Pentium4 days I was able to get multiple machines to run msieve LA (-nc2) and save time.

Recently I revisited this with a couple i7s to see if there could be a gain of anything. The answer that we all probably already knew, is not with Gigabit. With a relations set that took ~10 hours on one machine, it showed ~12 hours to ~22 hours (after settling) for the two machines, depending on various thread/grid combinations.

The one area that might be of use is if I can increase my memory capability by using two machines. This was something brought up by VBCurtis a while back. I haven't explored that to any extent, but if I need more than the 16G of one machine, perhaps I can use two and only lose some time (although possibly as much as 20%).
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