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

[Jim Mott]

If you want to avoid all the SM stuff, and are willing to program the
switches directly (a few mads), 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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