I have a system where I am doing the following on a PXA270 ARM system: An applications is sending and receiving a packet on a serial port every 40ms. With 2.6.20, I simply enabled kernel preemption and set the priority of my application to real-time, and it worked great, no matter what the system load. With 2.6.23-rc6, I have enabled CONFIG_HIGH_RES_TIMERS & CONFIG_PREEMPT. Scheduling in the real-time application is rock solid and looking at timing with a scope, and instrumenting the loop in the application indicates the 40ms is very solid. However, it seems the receive data is getting stuck in the serial driver for relatively long periods of time (>= 40ms), which is a problem in this system. Is there anything that would have changed between 2.6.20 and 2.6.23-rc6 that would explain this? What priority do pieces of the serial driver run at? Is there any way to make the serial driver run at high priority so that data is processed in a timely manner? Thanks, Cliff -- ======================= Cliff Brake http://bec-systems.com - 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
