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

[Hal Rosenstock]

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.

> 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
?

> 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

I agree with this table given the redefinition of M above and R > spec
response interpretation.

-- 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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