[Pw_forum] parallel processing

[Paolo Giannozzi]

On Aug 30, 2012, at 8:23 , somayeh fotohi wrote:

> I have two problems in quantum espresso.

no, you have one: you haven't read the user guide

>      davcio       :      0.01s CPU  23906.83s WALL (      88 calls)

this is I/O: more than 6h are spent reading and writing files. Either
your file system is very strange, or you are using a NFS-mounted
file system (very bad idea).

> when i use 32 cores or 16 cores, the speed does not change  
> considerably

maybe 32 cores are already too many for your system and/or for your
communication hardware

P.
---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222