Re: RDMA (smbdirect) testing

[Stefan Metzmacher <metze@samba.org>]

Hi Tom,

>>>> Can you share the capture file?
>>>
>>> See attached.
>>>
>>>> What version of wireshark are you using?
>>>
>>> wireshark-3.6.2-1.fc35.x86_64
>>> Wireshark 3.7.0 (v3.7.0rc0-1686-g64dfed53330f)
>>
>> Works fine for me with 3.6.2-2 on ubuntu and also a recent wireshark master version.
>>
>> I just fixed a minor problem with fragmented iwrap_ddp_rdma_send messages in
>> frames 91-96. Which seem to happen because ksmbd.ko negotiated a preferred send size of 8192,
>> which is accepted by the cifs.ko. Windows only uses 1364, which means each send operation fits into
>> a single ethernet frame...
> 
> That was not an accident. :)
> 
> There's a talk somewhere in which I mentioned how we tried to optimize
> the smbdirect fragment size and always landed back on 1364.

Yes, I remember 4096/3 :-)

> However, this is only an implementation choice, the protocol supports a wide
> range. So it's appropriate for wireshark to be accommodating.

Yes, but the past 20 years showed more than once that, everything but matching
Windows just leads to bugs, because of untested code paths.

>> See https://gitlab.com/wireshark/wireshark/-/merge_requests/7025
> 
> I get a blank frame when I view both changes on this link. Do I need
> a gitlab account??

I don't think so, I'm seeing it even without being logged in.

Does https://gitlab.com/wireshark/wireshark/-/merge_requests/7025.patch
or https://gitlab.com/wireshark/wireshark/-/merge_requests/7025/diffs
work?

metze