Hello, I was recently debugging a problem in our code base and tracked the issue down to differences between calling gettimeofday() from our non-realtime code and calling clock_gettime() from our realtime control loop. A little poking around with Google led me to clocktest program in the Xenomai testsuite. We are routinely seeing differences of around 4 minutes (~240 seconds) between gettimeofday() and clock_gettime() immediately after a reboot. The clocks continue to drift apart (or together) at the rate of about 50us/s.
My question is, is this large of a disparity between clocks normal? Are there any tricks or techniques for getting the clocks to be synchronized? In our application we have a realtime control loop reading data from motor control boards at a rate of 1KHz. The data is timestamped by the realtime loop. The non-realtime code can doing more heavyweight computation on that data. It uses the timestamp to correlate the data with other data read from non-realtime sensors (cameras, laser scanners, etc...). Some of this data may even be collected on other computers running on the robot (and connected via gigabit Ethernet). What do others do to synchronize time between realtime, non-realtime, and other network attached computers? A little more about my setup: kernel - 2.6.24.3 xenomai - v2.4.5 adeos patch - adeos-ipipe-2.6.24-x86-2.0-07.patch processor - 2.5 GHz Core 2 Duo Thanks for any info you can provide... -R _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
