[openib-general] IB/mthca: question about HCA profile module parameters

[Dotan Barak]

Hi Mini and thanks for the quick response.

Moni Shoua wrote:
> OK. So I ran more tests on my setup which now include
> - Dual x86_64 processor (Intel Xeon)
> - 1GB RAM
> - 25204 HCA - fw_ver=1.1.0
>
> In the range of 16K - to 256K of value for num_qp I got no errors.
> For lower and higher values I got errors from INIT_HCA and (not always and just for very low values) a machine hung.
> Do you have the Oops saved somewhere? Can you put it here please?
>
>   
Sorry but i don't have a dump of the kernel oops but i have a strong 
belief  that we saw the same  kernel oops ...
If it is needed, i will try to reproduce it one more time.
>   
>> Did you verify the HCA profile module parameter feature?
>>     
> As I mentioned earlier, I verified that non default values can be assigned 
> and that the HCA works for some selected values. 
> I also noticed that illegal cause the driver to throw a message to the kernel log.
> However, I didn't test the exact behaviout of all possible values for each profile variable.
>   
I guess that this is something that need to be done. i will add this to 
our regression in the future ....
>> Is there is any known limitation for the values that should be used?
>> (for example: only values which are power of two)
>>
>>
>>     
> I guess that it is clear that there are hardware limitations that don't allow setting of any value.
> Unfotunately, even after looking for them in the PRM, I couldn't figure out which are they.
> The software limits the value to be a power of 2 and corrects the users if they try to set a wrong value (to the nearest power of 2). In that case a warning message is thrown to the kernel log.
>   
As much as i know, the minimum amount of any resource (for example, QPs) 
are the number of resources that
the HCA report as reserved.

I will open a bug in the Bugzilla, so we will know that there are 
problems in this feature.

thanks
Dotan