[ofa-general] minimum sw components requirement for driver/opensm in a single unmanaged switch network

Hal Rosenstock hrosenstock at xsigo.com
Thu Jul 10 14:25:23 PDT 2008


On Thu, 2008-07-10 at 14:17 -0700, Jim Mott wrote:
> If you want to avoid all the SM stuff, and are willing to program the
> switches directly (a few mads), 

You would also need to walk the ports to active (via MADs) after setting
the LIDs as well as setup the switch forwarding table (LFT).

-- Hal

> then I’ve used schemes like:
> 
>  
> 
> Node LID=base + (switch port * constant) (base=0, constant = 1 works)
> 
>  
> 
> Then to figure out QP connections, you just use a function of 3
> parameters:
> 
>   my_qp_num = fn_sqp(my_node, target_node, qp_num)
> 
>   target_qp_num = fn_tqp(my_node, target_node, qp_num)
> 
> Where qp_num is a small number between 0 and the maximum number of QPs
> you need active between any 2 endpoints.  
> 
>  
> 
> With the above scheme, you know your node_id (switch port number),
> your lid, the lid of the target node,  and the QPs on both sides.
> From there on, it is clear sailing.  You don’t even need to send MADs;
> just transition the QP up and try and use it.  If it works, you are
> done.  If not, reset, up, wait for him to connect and send something
> to you.  A little timer to make sure everybody retries once in awhile
> and what can go wrong?
> 
>  
> 
> Jim
> 
> From:general-bounces at lists.openfabrics.org [mailto:general-
> bounces at lists.openfabrics.org] On Behalf Of Yicheng Jia
> Sent: Thursday, July 10, 2008 2:59 PM
> To: general at lists.openfabrics.org
> Subject: [ofa-general] minimum sw components requirement for
> driver/opensm in a single unmanaged switch network
> 
> 
>  
> 
> 
> Hi Folks, 
> 
> I have a IB network which consists of only a single unmanaged switch,
> all end nodes connecting with the switch only need to do RDMA
> read/write operation with each other. My question is, what are the
> indispensable modules in driver's core and opensm that make the
> network up and run? 
> 
> I've been using only ib_mad module in driver's core with a managed
> switch before, and the network works fine. So I assume that only the
> ib_mad module in driver's core and SM in opensm are mandatory in my
> network. The LIDs are assigned by them. The SA and CM modules are not
> useful in my case. Am I right? 
> 
> I need to minimize driver and opensm to fit them in my network, the
> HCA driver is mthca. 
> 
> Best, 
> Yicheng 
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