Which real-time priority is the highest priority in Linux

Question

In the Linux real-time process priority range 1 to 99, it\'s unclear to me which is the highest priority, 1 or 99.

Section 7.2.2 of \"Understanding the Linux Kerne

Answer 1

This comment in sched.h is pretty definitive:

/*
 * Priority of a process goes from 0..MAX_PRIO-1, valid RT
 * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
 * tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
 * values are inverted: lower p->prio value means higher priority.
 *
 * The MAX_USER_RT_PRIO value allows the actual maximum
 * RT priority to be separate from the value exported to
 * user-space.  This allows kernel threads to set their
 * priority to a value higher than any user task. Note:
 * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
 */

Note this part:

Priority values are inverted: lower p->prio value means higher priority.