High throughput networking does the same thing, it polls the network adapter rather than waiting for interrupts.
The cost is not high, it's much less expensive to have a CPU operating more efficiently than not processing anything because its syncing caches / context switching to handle an interrupt.
These libraries are for busy systems, not systems waiting 30 minutes for the next request to come in.
Basically, in an under utilized system most of the time you poll there is nothing wasting CPU for the poll, in an high throughput system when you poll there is almost ALWAYS data ready to be read, so interrupts are less efficient when utilization is high.
Running half the cores of an industrial Xeon or Zen under 100% load implies very serious cooling. I suspect that running them all at 100% load for hours is just infeasible without e.g. water cooling.
The cost is not high, it's much less expensive to have a CPU operating more efficiently than not processing anything because its syncing caches / context switching to handle an interrupt.
These libraries are for busy systems, not systems waiting 30 minutes for the next request to come in.
Basically, in an under utilized system most of the time you poll there is nothing wasting CPU for the poll, in an high throughput system when you poll there is almost ALWAYS data ready to be read, so interrupts are less efficient when utilization is high.