alt Hacker News> Context switching
No such thing. In a preemptive multitasking OS (that's basically all of them today) you will get context switching regardless of what you do. Most modern OS's don't even give you the tools to mess with the scheduler at all; the scheduler knows best.
That's not accurate. Preemptive multitasking just means your thread will get preempted. Blocking still incurs additional context switching. The core your thread is running on isn't just going to sit idle while your thread blocks.