bitlinux_arm_V5.0 build 1015, RS232 "No operations reported in timeout period"

[karry]

PassMark BurnIn Test Linux_bitlinux_arm_V5.0 build 1015, There are 16 COM ports, RS232, with a baud rate of 9600. During the 12-hour operation of Passmark, an error message "No operations reported in timeout period" appears. What could be the reasons for this error?

The other program was run on 16 COM ports for 12 hours, and the TX and RX received data were consistent.

[Richard (PassMark)]

"No operations reported in timeout period" indicates that the Operation count for the test did not increase between watch dog checks. The watch dog timer is 3 minutes.

"No operations" normally indicates a software crash or lock up in a device driver, so the COM port device driver for your serial ports may have a bug that caused it to crash during the test. Check that the latest drivers for the serial hardware is installed and if that doesn't help you should try decreasing the speed the ports are running at or the number of serial ports being tested at the same time.

Or if you are running on high load, you can try lowering the duty cycles of the other test.

[karry]

What is the maximum number of COM ports that can be simultaneously tested in Linux ARM version Burnin?

[David (PassMark)]

The code itself allows for up to 64 COM ports at the same time.
But,
1) Linux itself might not support this number. (Some Linux distros might have a limit of 32). Or the device driver for the I/O chips might not support this many.
2) We've never tested 64 ports at the same time, as we don't know of any easily available hardware with this many ports.
3) It will be unsurprising if at some point there was load related issues (timeouts and data overflows) once you have dozens of ports running.

I would repeat the 12h test with just the serial port test running. (i.e. without all the load from the CPU and RAM tests)