[Pw_forum] Computational Speed for pw.x

[Lorenzo Paulatto]

On 11/12/17 12:22, Amar Singh wrote:
> Similarly, varying -nk and -ni from 1 - 8 for -np 8 also does not effect 

Dear Amar,
I'm quite sure that the -ni option has strictly no effect on pw.x, as it 
only uses one image (-ni = number of images).

You should try -nk to set a number of pools (ideally, a factor of the 
number of k-points in your system) to see if you can achieve better 
scaling for more than 8 CPUs.

Not however, that running with more CPUs will apply more stress on the 
memory bandwidth, and potentially the disk. It may just be that your 
computer is not able to scale better for this application.

kind regards


-- 
Lorenzo Paulatto - Paris