[Nek5000-users] CPU, Memory and MPI

[nek5000-users at lists.mcs.anl.gov]

Hello Neks,I want to know specific information about optimal usage of computing sources.I would like to show you my own environment for running a case.CPU: 3.3 GHz, 4 cores, 8 processors (Intel i7-6700HQ)RAM: 2133 MHz, 8 GB x 1 (DDR4-2133)Case: 1500 elements, N = 61.Based on Nek5000 document, total memory requirement is1500 (points) X 6^3 X 400 (words/point) X 8 (bytes/word) X (1 GB/1024^3 bytes) = 0.97 GBSo, is this calculation correct? so is 8 GB of memory enough?2.In the Nek5000 document, they also mention about "memory per core."Could you tell me the meaning of memory per core?I thought that, in my case, I assigned 2GB / core (If I use MPI with 4 cores. because I also have 8 GB of memory).If there are manual way to assign, how can I assign memory to cores?3.Actually, I also tried to use nekbmpi to use MPI process in my PC.But when I type like belownekbmpi <case name> 8(or 4)my CPU usage of 8 processors suddenly goes up but, there are no progress in simulation.(log file is remained as 0 bytes. when I check 'Task manager' of Windows 10,Nek5000 processes appear but they take just few MB of memory, but usage of CPU peaked up to 100%)I also tried to use nek5000 directly as below./nek5000 -np 8(or 4) > case.out &But I think, after typing this syntax, PC shows just moderate performance (same performance with ./nek5000 ).(log file also shows Number of processors:     1)I already installed MPI in my ubuntu environment in Windows 10.Also I compiled make file with mpif77 and mpicc.How can I use MPI in my PC?4.Finally,If you have idea to estimate time to run your case approximately(e.g. cycle per second), please give me.And I will also appreciate if you show how to calculate the appropriate number of processors to run a case.(no matter if it is based on your environment or my environment)

Best Regards,Hyunduk.

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