Re: Why I get random task period ?

There seems to be an 1.4 us anticipation offset in the scheduling calibration, to be fixed by subtracting 1500 to the related .rtai_config values. 
For the rest it seems that the timing and the hardware are both OK. With such an evidence it is difficult for me to provide a clue for the problem you reported, as well as to understand why by programming the APIC by yourself fixes it. In fact if there were a problem it should have be shown by the latencies check you ran. It is not important but I'm curious to know what RTAI version you are using.
Paolo
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From: Rtai [[email protected]] on behalf of NULL [[email protected]]
Sent: Monday, August 14, 2017 6:25 AM
To: rtai
Subject: Re: [Rtai] Why I get random task period ?

Thanks for your reply.
Latency Test result is shown as below:

RTAI Testsuite - KERNEL latency(all data in nanoseconds)
RTH | lat min | ovl min | lat avg | lat max | ovl max | overruns
RTD | -1814 | -1814 | -1520 | 4758 | 4758 | 0
RTD | -1777 | -1814 | -1516 | 6728 | 6728 | 0
RTD | -1780 | -1814 | -1522 | 7118 | 7118 | 0
RTD | -1797 | -1814 | -1523 | 5847 | 7118 | 0
RTD | -1789 | -1814 | -1521 | 5865 | 7118 | 0
RTD | -1781 | -1814 | -1521 | 6584 | 7118 | 0
RTD | -1811 | -1814 | -1525 | 5971 | 7118 | 0
RTD | -1803 | -1814 | -1522 | 6010 | 7118 | 0
RTD | -1800 | -1814 | -1524 | 5290 | 7118 | 0
RTD | -1812 | -1814 | -1522 | 6904 | 7118 | 0
RTD | -1813 | -1814 | -1523 | 4897 | 7118 | 0
RTD | -1810 | -1814 | -1525 | 4310 | 7118 | 0
RTD | -1780 | -1814 | -1521 | 5488 | 7118 | 0
RTD | -1812 | -1814 | -1521 | 7805 | 7805 | 0
RTD | -1800 | -1814 | -1520 | 4630 | 7805 | 0
RTD | -1805 | -1814 | -1521 | 4790 | 7805 | 0
RTD | -1780 | -1814 | -1522 | 2878 | 7805 | 0
RTD | -1812 | -1814 | -1512 | 7631 | 7805 | 0
RTD | -1809 | -1814 | -1524 | 4715 | 7805 | 0


RTAI Testsuite - USER latency(all data in nanoseconds)
2017 / 08 / 14 12:13 : 01
RTH | lat min | ovl min | lat avg | lat max | ovl max | overruns
RTD | -1475 | -1475 | -888 | 6302 | 6302 | 0
RTD | -1469 | -1475 | -888 | 3952 | 6302 | 0
RTD | -1475 | -1475 | -888 | 6329 | 6329 | 0
RTD | -1475 | -1475 | -890 | 3178 | 6329 | 0
RTD | -1472 | -1475 | -886 | 5610 | 6329 | 0
RTD | -1478 | -1478 | -887 | 6673 | 6673 | 0
RTD | -1475 | -1478 | -888 | 3863 | 6673 | 0
RTD | -1476 | -1478 | -889 | 4385 | 6673 | 0
RTD | -1478 | -1478 | -989 | 5574 | 6673 | 0
RTD | -1478 | -1478 | -888 | 5732 | 6673 | 0
RTD | -1472 | -1478 | -889 | 6594 | 6673 | 0
RTD | -1478 | -1478 | -972 | 7568 | 7568 | 0
RTD | -1475 | -1478 | -887 | 4890 | 7568 | 0
RTD | -1477 | -1478 | -940 | 6457 | 7568 | 0
RTD | -1474 | -1478 | -887 | 6627 | 7568 | 0
RTD | -1474 | -1478 | -889 | 3106 | 7568 | 0

I don't think there's any problem.
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