> If your application really has to have accurate reliable timing then you will need to write a real time application and install a kernel built with the PREEMPT_RT patch https://rt.wiki.kernel.org/index.php/Main_Page otherwise you will be subject to the type of problem you are encountering.
Bill: Thanks for this note, I may be forced to go this route. Following a personal tip by Paul Hermann on using the "chrt" command to set the real time attributes, I thought I had the problem solved by using the "SCHED_FIFO" with 99 priority, but this morning, when my Ubuntu 12.04.2 LTS system ran the daily anacron job, the system suspended the nanosleep process again for about 0.06 seconds, which was enough to throw off the timestamping. I now have the anacron running at 12 midnight to 1 am, not at 7 - 8 am in the morning, right when the system is busiest! I have worked on kernels, I find it rather surprising that nanosleep at SCHED_FIFO priority 99 for a current existing task, is still taken out and laid on the shelf. It seems okay to delay new tasks, but to ignore an existing task at the highest schedule priority seems rather odd. Randall _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
