[j-nsp] Event Log RPD_SCHED_SLIP M20

[Juniper]

Hello there,

Since few days we are detecting these message in our log message in a 
Juniper M20 with the JUNOS version 7.3R1.4 :

Apr 6 06:00:15 xxxx-yyy2.abc-d.net LEV[2625]: RPD_SCHED_SLIP: 5 sec 
scheduler slip, user: 4 sec 940542 usec, system: 0 sec, 14925 usec
Apr 6 05:58:07 xxxx-yyy2.abc-d.net LEV[2625]: RPD_SCHED_SLIP: 4 sec 
scheduler slip, user: 4 sec 75182 usec, system: 0 sec, 0 usec

Does anyone know what could be the problem?

Thanks in advance,