Strange Jerk of Task Period

Hi, everyone, it's me again
I am using LinuxCNC with RTAI built in, and I build a program with five periodic tasks, with a period of 1ms 1ms 5ms 5ms 5ms.
The program runs well on an Advantech Emmbedded platform MIO5251
, but strange Jerk appears when I run it on ADLink Emmbedded platform TALOS3012, few (1 or 2)  intervals of the first periodic task can reach 4ms or 5ms while it is supposed to be 1ms, while other periodic tasks seems to be acceptable with a ripple around 10000 nano seconds. 

All the platforms have four cores, which provide enough computation capability for the scheduling of the real-time periodic tasks.
I can not figure out why this happens.......
Can anybody give me some instructions?
3Q~
 
                                                            yours: C.P.
                                                            2016-10-13

_______________________________________________
Rtai mailing list
[email protected]
https://mail.rtai.org/cgi-bin/mailman/listinfo/rtai