Hello, are there any plans to improve the latency with serial ttys and RT? I'm seeing very high latencies (up to 100 ms) when a high priority RT thread accesses a serial tty port. I'm working with 4.14.52-rt34 on a ARM system. The reason for this issue seems to be that a kworker thread with a normal priority is involved here. When the high priority RT thread needs to wait for this kworker thread, it can easily be blocked by other lower priority RT threads running in the system. I have seen that Steven Walter proposed some change in 2015, where this kworker thread in replaced by a kthread with a RT priority if the low_latency mode is selected. See: https://www.spinics.net/lists/linux-serial/msg17782.html The follow-up discussion in this thread also proposes a solution that allows low_latency ports to directly execute the worker. As interrupts are already threaded in PREEMPT_RT, wouldn't that be a solution? Please excuse me if I got something wrong. Thanks in advance. Andre -- 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
