> Real-time programs tend to avoid syscalls, etc. which cause a context switch That's not why they avoid syscalls. If you are running on a real time schedule t

> Real-time programs tend to avoid syscalls, etc. which cause a context switch That's not why they avoid syscalls. If you are running on a real time schedule there won't be a context switch in response to a syscall. They may, however, get blocked on kernel mutexes. So syscalls are avoided for the same reason user-space mutexes are avoided - being real-time doesn't help if you're blocked on a mutex.