Can I run multiple simulations simultaneously?

Dear all lammps users

This question will be the last question about parallel simulation.

I can use SKL (skylake) node with 2 CPUs (Xeon gold 6148 x 2) in facility.

I found that the simulation speed in my configuration is almost same between 1 CPU usage and 2 CPU usage in 1 SKL node (about 21 ns/day)/.

The gurus said I can only submit 1 job per 1 node, so run 1 simulation per 1 node.

But can I assign 2 simulations per each 2 CPU in 1 SKL node? I mean that by one in.* script, can I run 2 independent simulations simultaneously? (e.g. each 250K and 270K simulation)

If it would be possible, I can use these SKL node with actual half of the prices.

Any advices or opinion would be greatly helpful.

Dongwoo Kang

Dear all lammps users

This question will be the last question about parallel simulation.

I can use SKL (skylake) node with 2 CPUs (Xeon gold 6148 x 2) in facility.

I found that the simulation speed in my configuration is almost same between 1 CPU usage and 2 CPU usage in 1 SKL node (about 21 ns/day)/.

The gurus said I can only submit 1 job per 1 node, so run 1 simulation per 1 node.

But can I assign 2 simulations per each 2 CPU in 1 SKL node? I mean that by one in.* script, can I run 2 independent simulations simultaneously? (e.g. each 250K and 270K simulation)

yes, that is possible using the -p or -partition command line flag in LAMMPS: https://lammps.sandia.gov/doc/Run_options.html#partition

axel.

And this topic is discussed in the Howto section of the manual.
e.g. Section 8.2.3.

Steve

Dear Axel and Steve,

Thanks for kind replies.

I read documentations carefully your guys added in the replies.

If my understanding is correct, 2 independent simulation will run simultaneously with 250 and 270 K when I add <variable t universal 250 270>, bash in fix and in in.* script, and <-p 20 20> in the command line. Right ?

Dongwoo Kang

2019년 3월 25일 (월) 오후 7:31, Axel Kohlmeyer <[email protected]>님이 작성:

please make a test and see for yourself. this is a mailing list and not an input file approval service. axel.