GPUs were chosen by growing one card's NVLink peers, which took cards
each joined to that one but not to each other, and knew nothing of the
fabric. Every set of the right size is now scored - a node's handful of
cards makes that cheap - by NVLink pairs within it, then for a
multi-node shard by how near each card is to one of the fabric's
adapters (PIX before SYS), then by NUMA nodes spanned, with the lowest
indices breaking ties. A node without topology still gets the lowest
indices.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
