Hello Cliff, On Tue, Mar 10, 2009 at 1:44 PM, Cliff Brake <cliff.brake@xxxxxxxxx> wrote: > Clarification, I don't have the RT patch applied, just CONFIG_PREEMPT > from Linus's kernel. Reviewing my notes from several years ago, I ran > into a similar issue and the RT patch fixed it, so now to figure out > the best way to get a recent RT patched ARM kernel ... > >> timing. However, it seems that the system has trouble receiving the >> response in a timely fashion. I often observe that it takes at least >> 10ms for the application to receive the response data after the data >> has appeared on the rs232 bus. Is the RT patch something that would We are running a real-time RS-485 protocol where the time window is 1 ms and only under heavy load we got deadline misses > 1 ms. Unfortunately I didn't measure the max latency then, but 10 ms sounds like excessive latency to me. Under 2.6.24.7-rt24 (or whatever -rtxy in that series) we have never missed the 1 ms deadline. That's on XScale IXP4xx @533 MHz, Regards, -- Leon -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
