In order to understand the hashing logic of slurm and see where was the

limitation in terms of scalability, I did some tests with cluster sizes
varying from 64 to 64k nodes. I saw the same kind of performance issues
that you saw with large sizes (more than a few thousands nodes).

Looking at the code, I noticed that the hash table of the node records
was not built before the construction of the topology information in
slurmctld ! Making sure that the hash table is present really reduces
the built time.

This patch ensures that and enable to get sub-second built time
for topology information in scenarios that were used to require a
minute before.

I think that using this patch, the load time of slurm confs is less
problematic.