Re: [Xenomai-help] Smi workaround on ICH8M

[Willy Lambert <lambert.willy@domain.hid>]

2012/4/23 Willy Lambert <lambert.willy@domain.hid>:
> 2012/4/23 Philippe Gerum <rpm@xenomai.org>:
>> On 04/23/2012 03:51 AM, Willy Lambert wrote:
>>>
>>> Hi,
>>>
>>> I have a message  in dmesg about SMI workaround :
>>> Xenomai: SMI-enabled chipset found, but SMI workaround disabled
>>>          (check CONFIG_XENO_HW_SMI_WORKAROUND). You may encounter
>>>          high interrupt latencies!
>>>
>>> My kernel should be configured properly and following the "In case of
>>> high latencies" of
>>> http://www.xenomai.org/index.php/Configuring_x86_kernels thread, I did
>>> some tests.
>>>
>>> Latency test is here (if it is us it should be ok no ?):
>>>
>>
>> Yes, this looks ok, but you need to run this test longer, and try a few
>> usual suspects like plugging in/out USB devices while doing so (e.g. mouse,
>> netdev).
>>
>> The point of this message is to tell you that your chipset is known to
>> create latency issues in some cases (like most Intel chipset these days),
>> but you did not enable the Xenomai code which works around such issues by
>> shutting down problematic SMI sources. That may be right, or even required
>> to leave all the SMI sources enabled (e.g. thermal control), but this might
>> also lead to unacceptable latency spots. YMMV.
>>
>> This is basically a heads up message.
>>
>> --
>> Philippe.
>
> Ok, thanks for answers.
>
> I did the test again , playing with usb and using the stress program
> to generate CPU load. The max latency for now is 15us in 4 mins. So I
> think it will be ok to keep SMI on for the time. Please let me know if
> this test is still stoo short.
> ^C---|-----------|-----------|-----------|--------|------|-------------------------
> RTS|      0.604|      2.332|     15.161|       0|     0|    00:03:59/00:03:59
>
> Do you know by chance where I can found infos about SMI sources ? I
> suppose it is not in the ICH8M docs, it would be in my board doc ? Or
> have I a soft way to do this check so that I don't have to spend time
> with my vendor which will obviously have hard time to answer that ?

Btw is there any way to test latencies without xenomai (or in
secondary mode) to compare ?