Add to logical interfaces-

        per-unit-scheduler;

Example-
    irb {
        per-unit-scheduler;


Then add this whole section-

class-of-service {
    classifiers {
        dscp ClassMap {
            forwarding-class assured-forwarding {
                loss-priority low code-points 011000;
            }
            forwarding-class expedited-forwarding {
                loss-priority low code-points [ 101000 101110 011010 ];
            }
            forwarding-class best-effort {
                loss-priority high code-points 000000;
            }
        }
    }
    code-point-aliases {
        dscp {
            cs5 101000;
            voice 101110;
        }
    }
    forwarding-classes {
        queue 0 best-effort;
        queue 1 assured-forwarding;
        queue 2 expedited-forwarding;
        queue 3 network-control;
    }
    interfaces {
        ge-0/0/* {
            scheduler-map smap1;
            unit 0 {
                classifiers {
                    dscp ClassMap;
                }
            }
        }
        irb {
            unit * {
                scheduler-map smap1;
                classifiers {
                    dscp ClassMap;
                }
            }
        }
    }
    scheduler-maps {
        smap1 {
            forwarding-class best-effort scheduler best-effort-scheduler;
            forwarding-class expedited-forwarding scheduler expedited-scheduler;
            forwarding-class assured-forwarding scheduler assured-scheduler;
            forwarding-class network-control scheduler strict-priority-scheduler;
        }
    }
    schedulers {
        strict-priority-scheduler {
            buffer-size percent 5;
            priority medium-high;
        }
        expedited-scheduler {
            transmit-rate percent 55;
            buffer-size percent 70;
            priority strict-high;
        }
        assured-scheduler {
            transmit-rate percent 30;
            buffer-size percent 15;
            priority medium-low;
        }
        best-effort-scheduler {
            priority low;
        }
    }
}