int sched_rr_interval(int pid, struct timespec *new, struct timespec *old);
This syscall fetches and/or sets current quantum periods for the passed process
for use under SCHED_RR scheduling policies.
If pid is 0, the PID of the caller is used. Both the new and
old values are nullable.
This syscall returns 0 on success or -1 on failure, with the
following errno:
EFAULT: One of the passed buffers was not 0 and not accessible.
ESRCH: Invalid PID passed.
EPERM: MAC did not allow the operation.