COM port loopback test & settings

[BrooksL]

Hi Ian,

I was using the stock Windows serial port drivers in Win2k and WinXP. I tried installing the Intel chipset INF update utility for the E7520 + 6300ESB chipset on the Win2K machine and no change in error behavior (I don't think it has any Intel specific serial port driver in the INF update).

The error almost always occurs on one of the com ports at the beginning of the test, but not always on the same com port. The error does occur again once in a while on each port as the test continues.

No other Passmark tests are running and no other software other than the Windows OS tasks that run after a basic Windows install and boot.

Can you tell me if the 'send data to com port' routine depends upon a receiving a transmitter-empty interrupt? There is an Intel errata about the transmitter empty interrupt on the 6300ESB but Intel considers it minor enough that they didn't see a need to change it. I guess they figure it shouldn't cause a problem for well-behaved drivers.

Thoughts? Could this also be related to the drop in throughput when multiple com ports are tested at the same time?

[Ian (PassMark)]

It is hard to say, but it sounds possible. It would seem likely that this is a hardware problem.

Regards,
Ian

[BrooksL]

Serial port test error while sending and 1/2 throughput

Ian,

So, the errors do not seem realated to the Intel 6300ESB ICH UART IRQ errata. I found another motherboard with the 6300ESB and ran WinXP SP2, BIT 5.3 serial tests.

I did not get the "error while sending data to COM port" but I still get the 1/2 expected throughput when testing both ports. What have you guys found on this 1/2 throughput issue?

Another difference with the failing motherboard model is that it's a dual-core Xeon processor and chipset. Could that be a problem for BIT using the included WinXP serial port drivers?

Please advise.

[BrooksL]

Ian,

Actually, the failing model I'm testing with is not a dual-core Xeon, but a dual processor board with a single processor installed and Intel Hyper-threading enabled (which makes it act like dual-cores in some ways).

After I disable Hyper-threading in the BIOS Setup, the error rate drops significantly to just a few per 150 cycles.

Again, the error occurs only when testing both COM ports which reside in the Southbridge, at the same time. If one or both ports under test are not in the Intel 6300ESB ICH southbridge, then there is little problem.

So, what are the known and potential issues when testing COM ports with dual processors and/or Intel Hyper-threading enabled?

Please advise.

[Ian (PassMark)]

I don't know of any issues with this configuration.

Regards,
Ian

[elic]

serial port test

after several hours of testing(More than 10 hours),some serial port test will stop(report "no errors","throughput:0Bytes/sec" ).even if pull out loopback,burnintest just the same "no errors",however the other serial port test runing.

[Ian (PassMark)]

BurnInTest runs a test for each serial port simultaneously. With BurnInTest V6.0 you should get a "No operations reported in timeout period" for each serial port that has no operations in at least 8 minutes.

If you are using BurnInTest v6.0, you can email me level 2 trace files files with 1 minute periodic logging for this test I can investigate further. Email address:
http://www.passmark.com/support/index.htm