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

Yicheng Jia YJia at tmriusa.com
Thu Aug 28 12:09:39 PDT 2008


I missed it. So it's better to keep opensm running all the time?

Thanks!
Yicheng



Hal Rosenstock <halr at obsidianresearch.com> 
08/28/2008 06:31 AM

To
Yicheng Jia <YJia at tmriusa.com>
cc
Dotan Barak <dotanba at gmail.com>, general at lists.openfabrics.org
Subject
Re: [ofa-general] minimum sw components requirement for driver/opensm in a 
single unmanaged switch network






Yicheng Jia wrote:
> Yes. My basic idea is, the opensm set up the subnet during 
initialization, 
> it will report errors during this process. After the subnet is up, the 
> environment is fixed and stable. If some failure happens, opensm could 
be 
> used again to diagnose the failure. From my understanding, in this case, 

> the only work that opensm does after subnet is up is to log the status.
Wouldn't opensm also repair the failure if it could ?

-- Hal
> 

> Thanks!
> Yicheng
>
>
>
>
> Hal Rosenstock <halr at obsidianresearch.com> 
> 08/27/2008 05:55 PM
>
> To
> Yicheng Jia <YJia at tmriusa.com>
> cc
> Dotan Barak <dotanba at gmail.com>, general at lists.openfabrics.org
> Subject
> Re: [ofa-general] minimum sw components requirement for driver/opensm in 
a 
> single unmanaged switch network
>
>
>
>
>
>
> Yicheng Jia wrote:
> 
>> My operation is quite simple: connect QPs and do RDMA read/write. In 
>> 
> this 
> 
>> case, the opensm is not in need when the subnet is up, correct?
>>
>> 
> Is this a production subnet ? Do you need to deal with any failures ?
>
> -- Hal
>
> 
>> Thanks!
>> Yicheng
>>
>>
>>
>>
>> "Dotan Barak" <dotanba at gmail.com> 
>> 08/21/2008 02:33 PM
>>
>> To
>> "Yicheng Jia" <YJia at tmriusa.com>
>> cc
>> "Hal Rosenstock" <hal.rosenstock at gmail.com>, 
>> 
> general at lists.openfabrics.org
> 
>> Subject
>> Re: [ofa-general] minimum sw components requirement for driver/opensm 
in 
>> 
> a 
> 
>> single unmanaged switch network
>>
>>
>>
>>
>>
>>
>> On Thu, Aug 21, 2008 at 10:16 PM, Yicheng Jia <YJia at tmriusa.com> wrote:
>>
>> 
>>> Hi Hal,
>>>
>>> Can opensm just run once? When the subnet is up, it can exit assume 
>>> 
> that 
> 
>> no
>>
>> 
>>> change will be made in the subnet.
>>>
>>>
>>> 
>> Yes, depend on the serives that you will need/use.
>>
>> For example: if you use operations that requires SA query, you must
>> have a live SM.
>>
>> If you will connect the QPs in the subnet by yourself (for example,
>> using socket) you can manage without a live SM in the subnet ...
>>
>> Dotan
>>
>> 
>>> Thanks!
>>> Yicheng
>>>
>>>
>>>
>>> "Hal Rosenstock" <hal.rosenstock at gmail.com>
>>>
>>> 07/10/2008 09:15 PM
>>>
>>> To
>>> "Yicheng Jia" <YJia at tmriusa.com>
>>> cc
>>> "Jim Mott" <jim at mellanox.com>, general at lists.openfabrics.org
>>> Subject
>>> Re: [ofa-general] minimum sw components requirement for driver/opensm 
>>> 
> in 
> 
>> a
>>
>> 
>>> single unmanaged switch network
>>>
>>>
>>>
>>>
>>> On Thu, Jul 10, 2008 at 7:39 PM, Yicheng Jia <YJia at tmriusa.com> wrote:
>>>
>>> 
>>>>> If you want to avoid all the SM stuff, and are willing to program 
the
>>>>> switches directly (a few mads)
>>>>>
>>>>> 
>>>> Is it done by opensm?
>>>>
>>>> 
>>> Yes.
>>>
>>>
>>> 
>>>> What information should be set up in the switch by
>>>> opensm?
>>>>
>>>> 
>>> Things like the PortInfos and LFT. See IBA spec vol 1 14.2.5
>>>
>>>
>>> 
>>>>> 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.
>>>>>
>>>>> 
>>>> Can the qp_num be manually assigned?
>>>> Does it need opensm be involved?
>>>>
>>>> 
>>> SM has nothing to do with QP numbers.
>>>
>>>
>>> 
>>>>> If it works, you are done.  If not, reset, up, wait for him to 
>>>>> 
> connect
> 
>>>>> and
>>>>> send something to you.
>>>>>
>>>>> 
>>>> Is it reliable? I mean the QPs connection will keep alive during the 
>>>>
>>>> 
>> QPs
>>
>> 
>>>> lifecycle?
>>>>
>>>> 
>>> For one thing, SM needs to try to keep ports at active.
>>>
>>> -- Hal
>>>
>>>
>>> 
>>>> Best,
>>>> Yicheng
>>>>
>>>>
>>>>
>>>> "Jim Mott" <jim at mellanox.com>
>>>>
>>>> 07/10/2008 04:17 PM
>>>>
>>>> To
>>>> "Yicheng Jia" <YJia at tmriusa.com>, <general at lists.openfabrics.org>
>>>> cc
>>>> Subject
>>>> RE: [ofa-general] minimum sw components requirement for driver/opensm 

>>>>
>>>> 
>> in a
>>
>> 
>>>> single unmanaged switch network
>>>>
>>>>
>>>>
>>>>
>>>> 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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