[openib-general] tavor quirks etc (opensm compliance etc)

[Eitan Zahavi]

Hal Rosenstock wrote:
> Hi Eitan,
>
> On Sun, 2006-12-24 at 07:35, Eitan Zahavi wrote:
>   
>> Hi Or,
>>
>> Sorry it took me a while.
>>
>> According to the IBTA spec:
>> 1. In order for MTU and MTUSelector to have any effect their component 
>> mask bits MUST be set to 1 in the query
>> 2. Behavior of the SM is defined with small "freedom" to choose between 
>> multiple matching MTU values if they exist.
>>     
>
> I agree in general but would like to be sure about the details. Please
> be specific as to what IBA spec text you are referring to.
>   
The text is part of the PathRecord table.
>   
>> 3. The table below summarizes all options:
>>
>> Assuming the value M represents the lowest MTU on the path
>>     
>
> Is M the lowest available MTU or the highest available MTU for that path
> ?
>   
M is the lowest MTU reported by all PortInfo for ports on the path.
>   
>> We denote by M-1 the MTU value one level below M (e.g. 1K if M=2K)
>> R represents the MTU value in the request. Similarly R-1 is one below R 
>> and R+1 is one above R.
>>
>> Query-MTU | Query-Sel | Resp by Spec     | OpenSM Should  | OpenSM Quirk 
>> w. Tavor End Port
>> -----------------------------------------------------------------------------------------
>> UNDEFINED | UNDEFINED | <= M             | M              | min(M,1K)
>> R         | <         | <= min(R-1, M)   | min(R-1, M)    | min(R-1, M, 1K)
>> R         | =         | R if M>=R /ERR   | R if M>=R /ERR | R if M>=R /ERR
>> R         | >         | R < <= M         | R+1 if M>R /ERR| R+1 if M>R /ERR
>>     
>                           ^^^^^^^^
> For the R> spec response column, I think you are saying the same as:
>                        >R AND <=M if M>R /ERR
>                          or
>                        R < x <=M if M>R /ERR
>                        where x is resp value
>   
Yes that is what I mean: the response value MUST be both bigger then R 
and equal or less to M. Otherwise an error.
> I agree with this table given the redefinition of M above and R > spec
> response interpretation.
>   
Good.
> -- Hal
>
>   
>> I have built some test code for making sure OpenSM does what is required.
>> Apparently it does not. In any case the M is not identical to R it fails 
>> the request.
>>
>> I am working on fixing OpenSM.
>>
>> Any comments are welcome.
>>
>> EZ
>>
>> Or Gerlitz wrote:
>>     
>>> Michael S. Tsirkin wrote:
>>>   
>>>       
>>>> I am not yet sure what is best for upstream, so I don't really think we need
>>>> any RFCs.
>>>>     
>>>>         
>>>   
>>>       
>>>> We'll need data from SM guys on whether MTU selector actually works
>>>> in SMs, and if not what happens when you enable it.
>>>>     
>>>>         
>>> Eitan,
>>>
>>> Can you please post here the tavor-quirk patch which was integrated into 
>>> opensm? i can see the ***code*** of the opensm but might make some wrong 
>>> assumptions or get into wrong understandings as i am not able to see the 
>>> patch as is.
>>>
>>> Or.
>>>
>>>
>>>
>>>
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>>>   
>>>       
>
>
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