Hello, I have read the topic about performance of a machine with 2 dual-core chips, and it is written that with -np 2 it should scale the best. I would like to ask about 4-core machine.
I run the test on a quad core machine with mpiexec -n 1, 2 and 4 to see the parallel scaling. The cpu times of the test are: Solver/Precond/Sub_Precond gmres/bjacobi/ilu -n 1, 1917.5730 sec, -n 2, 1699.9490 sec, efficiency = 56.40% -n 4, 1661.6810 sec, efficiency = 28.86% bicgstab/asm/ilu -n 1, 1800.8380 sec, -n 2, 1415.0170 sec, efficiency = 63.63% -n 4, 1119.3480 sec, efficiency = 40.22% Why is the scaling so low, especially with option -n 4? Would it be expected to be better running with real 4 CPU's instead of a quad core ship? Regards, Jarunan -- Jarunan Panyasantisuk Development Engineer ASCOMP GmbH, Technoparkstr. 1 CH-8005 Zurich, Switzerland Phone : +41 44 445 4072 Fax : +41 44 445 4075 E-mail: jarunan at ascomp.ch www.ascomp.ch
