rabbitmq: with hundreds of celery workers, beam.smp consumes > 200% CPU
I didn't manage to actually solve this, but I worked around it by reducing the number of workers and increasing the concurrency. Seems like there's a per-worker overhead for rabbit...
So instead of
celery multi start -A proj 240 -c2
I now do
celery multi start -A proj 20 -c24
FWIW