Yeah, we've been bitten by horrible degradation as soon as anything else is running on the system next to the main application, like a cron job or unknowingly r

Yeah, we've been bitten by horrible degradation as soon as anything else is running on the system next to the main application, like a cron job or unknowingly running CI on a VM where the VM's vCPUs are subject to preemption. As long as you aren't oversubscribing hardware threads, you'll be fine, but at the cost of pathological behavior once you add just a single additional thread. Also don't use `sched_yield(2)` for spin locks, unless you're running priority-based RT Linux. A scheduler that is good for that scenario tends to be quite bad at most real-world scenarios that don't try to do their own spinlocks in userspace due to NIH syndrome.