[FLASH-USERS] Scaling problems

[pedro romero]

Hi Paco,

As far as I know, using uniform grid fixes the number of blocks as one per processor. Am I wrong? Do you mean to fix nxb and nyb while varying the cores?

De: Francisco Holguin <opaco at umich.edu>
Enviado el: miércoles, 5 de abril de 2023 15:17
Para: pedro romero <pedro.romero at greentownsbyfusion.com>
CC: flash-users at flash.rochester.edu
Asunto: Re: [FLASH-USERS] Scaling problems

Hi Pedro,

What if you just fix the number of blocks, and vary the cores?

-Paco

On Wed, Apr 5, 2023 at 5:13 AM pedro romero <pedro.romero at greentownsbyfusion.com<mailto:pedro.romero at greentownsbyfusion.com>> wrote:
Hi all,

I am trying to scale up on computational resources and I came across a few issues. First of all, I am running the same +ug example (a modification of 2D Zpinch template) varying the number of cores, nxb and nyb but it shows no speed up as the number of cores increase (I am tuning Iprocs, Jprocs, nxb and nyb to always get an approximately equal grid).

Furthermore, at a certain number of cores the program execution interrupts, and I get a SIGBUS error (which I attach to this message). Am I missing something? Is there any additional thing to consider?

I will also attach the log file of one successful run using 36 cores and nxb=nyb=16 (which shows little or no speed up in comparison to a run on 12 cores and nxb=nyb=28). Thank you in advance for any help.

Pedro


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