[Pw_forum] Output and parallelization problem in pw.x

[Lawrence Lee]

Dear all,

I have serveral problems about pw.x.

The performance of pw.x running in parallel under inter-node, is unreasonbly poor (about 25%). Later, I type sar to check, and find that something called "contextswitch" appears very frequently. But when pw.x is run under intra-node process, the problem did not occur and the performance become very good (>90%).  I think that "contextswitch" cause the problem. But why did it occur and how to fix the problem?

The second problem is about output file of pw.x. I want to get the stress tensor of each step of a pw.x (not cp.x) molecular dynamic run. I know that they exist in the standard output file. But the format is very inconvenient for further proccessing. Do anyone know is there any flag which can be specified to output a file of stress?

Thanks a lot!

Lawrence

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