Domain decomposition dominating computational cost

From: Leonard Romano <>
Date: Wed, 9 Jun 2021 17:09:43 +0200

Dear gadget-list members,

When I am running cosmological simulations with Gadget-4 I notice that
the domain decomposition becomes a dominant part of the computational cost.

I am running a simulation with 256³ gas and DM particles on 44 Intel
Xeon (e5-2699a v4) nodes, and the domain decomposition keeps getting
overwhelmingly expensive (20%-50% of the total CPU time). Curiously with
the same settings but only 2x128³ particles it only takes about 10%.
 From a quick glance at the code-paper I would have expected the
opposite behavior.

Attached are the config-options I compiled with and my parameters.
I would be very grateful if someone has any suggestions or comments
about how to improve or understand this behaviour.


Leonard Romano, B.Sc.(レオナルド・ロマノ)
Physics Department
Technical University of Munich (TUM), Germany
Theoretical Astrophysics Group
Department of Earth and Space Science
Graduate School of Science, Osaka University, Japan
he / him / his

Received on 2021-06-09 17:09:48

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