Make memory interleaving the default NUMA memory policy

Interleaving memory across NUMA regions has been an option in SWIFT for a few years now and it it probably time to make it the default. On AMD machines like COSMA8 it exploits the available memory bandwidth and it is recommended on that machine. On machines where using an MPI rank per NUMA region is best, then this option has no effect. It has also become true that MPI libraries that use UCX also benefit from this option as well.

This toggles the --interleave option replacing it with --nointerleave just for completeness.

added Configuration feature request labels

assigned to @matthieu

Guess there is a question of whether to retain --interleave as a noop to support backwards compatibility.

changed the description

mentioned in merge request !1708 (merged)

All good for me, thanks.

As for the backward compatibility, I guess we have really been the only ones using it so I don't think it's necessary. What do you think?

It is a simple change to make, as long as it is obvious what the error is, it is this point which gave me a moment of thought.

What we'll see is just a report of the command-line parameters that are valid, not that one disappeared. Think I'll go safe on this.

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• 28ba4420 - Accept --interleave and warning about deprecation

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Pushed changes to accept --interleave but make it clear that it is deprecated.

If we had a policy we'd know when that would be removed, but I leave that for the future...

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• a6b2f8fb - Formatting

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Thanks!

merged

mentioned in commit 53700b8b

One further wrinkle was we now assume NUMA support, so the check for this needed to be made into a warning otherwise all runs without NUMA support exit in error. See: 9141a9a8.