Hi, I'm having the same problem. In my RT application, running currently at kernel 4.9.13-rt12, a high priority thread communicates with a tty serial port. This thread is checking for incoming characters with a non-blocking read() call. The execution time of this read() call is normally within some hundreds of microseconds. In case some lower priority thread/process accesses some other tty, e.g. for console output, the non-blocking read() execution time within the high priority task rises to hundreds of milliseconds. After reverting the OpenSSH patch that Niels Kolthoff mentioned, I do no longer see these big delays inside the non-blocking read(). However, now the high priority task does not receive any characters from the tty serial port during these long periods. The non-blocking read() returns -1, although there must be characters available. This leads to timeouts in my application. So just reverting this patch is no workaround for me. Any ideas how to solve this issue are very welcome. Regards, 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
