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

[Eitan Zahavi]

Or Gerlitz wrote:
> 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.
>> 3. The table below summarizes all options:
>>
>> Assuming the value M represents the lowest MTU 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
>>     
>
> Hi Eitan,
>
> Not that it matters too much for the decision if to push this into the 
> Open SM, but the SM group here is positive w.r.t to the approach and 
> patch you have sent.
>
> However, there are some clarifications i will be happy to get:
>
> 1st maybe its clear to everyone expect me, but what do you mean by /ERR 
> in the table above, is it what opensm would return before the patch you 
> suggested?
>   
Hi Or,

By ERR I mean that the path being evaluated is rejected from being 
included in the paths group of the response to the provided query.

> 2nd can you post the open sm tavor quirk patch?
>   
What do you mean? The old patch introducing the "opensm quirk" mode?
It is GIT versions: 86077144ed956ddb32a0f8d067d5bb00fd564ac6 followed by 
03e3b3a6fa934202c0f4270a2c69d64ac486b1ca
or SVN: 9497 followed by 9518
> 3rd Eitan/Michael: what is the bigger picture here? what is the 
> dependency between these four patches
>
> +1 osm:Fix PathRecord bug MTU/rate/PktLife explicitly ignoring selectors
>   
Required - OpenSM broken otherwise
> +2 osm: tavor quirk
>   
Required - if want to rely on OpenSM for selecting 1K MTU for Tavor 
paths if it has the freedom to do so
> +3 IB/rdmacm: tavor quirk
> +4 IB/ipoib: use appropriate mtu selector for path queries
>   
I will let Michael answer that
> for example is it correct that:
>
> if [2] is applied on the SA side then [4] must be applied on ipoib else 
> if will get 1K mtu on its path query?
>
> if [2] is not applied on the SA side, then [3] is useless?
>
> Or.
>
>
>
>
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