To improve balancing when reading in 1 < CL < ALL
This implementation has a moderate impact on
the function performance in contrast to full
std::shuffle of the vector before stable_sort:ing it
(especially with large number of nodes to sort).
Before:
test iterations median mad min max allocs tasks inst cycles
sort_by_proximity_topology.perf_sort_by_proximity 25541973 39.225ns 0.114ns 38.966ns 39.339ns 0.000 0.000 588.5 116.6
After:
sort_by_proximity_topology.perf_sort_by_proximity 19689561 50.195ns 0.119ns 50.076ns 51.145ns 0.000 0.000 622.5 150.6
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
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