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From: Bob Pearson <rpearsonhpe@gmail.com>
To: Edward Srouji <edwards@nvidia.com>, Jason Gunthorpe <jgg@nvidia.com>
Cc: linux-rdma@vger.kernel.org, Leon Romanovsky <leon@kernel.org>
Subject: Re: py verbs tests
Date: Tue, 13 Oct 2020 09:22:52 -0500	[thread overview]
Message-ID: <57ecdc40-9c71-a543-a692-032c19f95e08@gmail.com> (raw)
In-Reply-To: <585b94bf-cd80-f135-0823-b68c7ce9fcdb@nvidia.com>

On 10/12/20 5:31 AM, Edward Srouji wrote:
> 
> On 10/8/2020 10:07 PM, Jason Gunthorpe wrote:
>> On Fri, Oct 02, 2020 at 04:34:22PM -0500, Bob Pearson wrote:
>>> I am currently trying to figure out why one of the pyverbs tests is failing.
>>>
>>> I added a check implementing C9-205 (p 419) of the IBA spec. I requires that a responder receiving a packet longer
>>> than the receive buffer or the PMTU shall be silently dropped. I.e. a class D error.
>>>
>>>      C9-205: Before executing the request, the responder shall validate the
>>>      Packet Length field of the LRH and the PadCnt of the BTH as described
>>>      in 9.8.3.2.2: Responder - Length Validation.
>>>      The following characteristics shall be validated:
>>>      • The Length fields shall be checked to confirm that there is sufficient
>>>      space available in the receive buffer specified by the receive WQE.
>>>      • The packet payload length must be between zero and PMTU bytes
>>>      inclusive in size.
>>>      If a packet is detected with an invalid length, the request shall be an invalid
>>>      request and it shall be silently dropped by the responder as specified in
>>>      Section 9.9.3 Responder Side Behavior on page 435. The responder then
>>>      waits for a new request packet.
>>>
>>> tests/test_cq_events.py passes PATH_MTU = 1024 in the modify QPs verb for RC and XRC but not UD.
>>> This should be a required parameter as part of the primary destination address but is not getting
>>> set for UD. The test then proceeds to send a 1024 byte payload to the destination and for UD hangs
>>> waiting for the completion.
>>>
>>> I don't want to mess with these tests because I am a poor python coder. Is there some reason why it is
>>> OK to not set the PMTU for UD QPs?
>> Edward is the person to ask about the tests..
>>
>> It seems like you are right and it should be set for UD too, if it is
>> not set what is the default?
>>
>> Jason
> 
> AFAIK PATH_MTU (when modifying a QP) is valid only for connected types (e.g. RC/UC etc.). It's not valid for UD. If you look at the code you may see that modify_qp does not update the PMTU according to the user attribute.
> 
> There is a default PMTU set for UD (usually it's the maximum PMTU).
> 
> Edward.
> 
> 
Totally agree. Sorry for the wild goose chase. 

      parent reply	other threads:[~2020-10-13 14:22 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-02 21:34 py verbs tests Bob Pearson
2020-10-02 21:41 ` Bob Pearson
2020-10-08 19:07 ` Jason Gunthorpe
     [not found]   ` <585b94bf-cd80-f135-0823-b68c7ce9fcdb@nvidia.com>
2020-10-13 14:22     ` Bob Pearson [this message]

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