I think the value returned by the gettimeofday function will probably have a worse resolution on the MOXA board than it has on the PC. That will make it difficult to get a low offset value, as the gpsd process sends the gettimeofday value at the time of the PPS pulse to ntpd via the shared memory block. That is how the shared memory (SHM) interface works. When the gettimeofday on the MOXA board only returns values with a 10ms or 20ms resolution, the jitter value will be high and the offset will never be very low. On the PC platform, various methods are used to get a very good resolution on the gettimeofday function. The chips on your board may not have that information available.
You could compile a simple test program like this: #include <stdio.h> #include <sys/time.h> main () { struct timeval t; int i; for (i = 0;i < 25;i++) { gettimeofday(&t,NULL); printf(" %ld.%06ld\n",t.tv_sec,t.tv_usec); } } Then run it. Try it on your different boards. You will see if there is some big increment in the printed value, ideally you should see only small steps in the last digit. _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions