Hello, I want to check how accurate the functions rt_get_time() of RTAI and gethrtime() of RTLinux are, and to draw a comparison between these two functions. To do so, I connected two PCs through a parallel wire. On each PC, one of the two RT systems is running. One PC is considered as a sender. A periodic task wakes up every millisecond, gets time, writes on the parallel port. The other PC is considered as a receiver. It's waiting for an interrupt coming from the 'sender' PC. Each time an interrupt occures, the associated handler wakes up and gets time. After a quick glince at the different measured times (those of the sender, and those of the receiver), I discovered that : - the periodic task (that is to say the sender) wakes up every millisecond, as expected ; - the handler (the receiver) does not wake up every millisecond ! There's a drift. The first measured times are OK, not so far from those of the sender, but after a while, it's not good anymore. The results remain the same, whatever the RT system is used for the sender or the receiver. I tried the four possibilities, and each time there was a drift. Thus, when the receiver is running under RTAI, it's an increasing drift, whereas it's a decreasing one when the receiver is running under RTLinux. I would greatly appreciate your help. Sebastien ----- End of forwarded message from [EMAIL PROTECTED] ----- -- [rtl] --- To unsubscribe: echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED] -- For more information on Real-Time Linux see: http://www.rtlinux.org/
