From: John Fastabend <john.fastabend@gmail.com>
To: Shachar Raindel <raindel@mellanox.com>
Cc: Or Gerlitz <gerlitz.or@gmail.com>,
Or Gerlitz <ogerlitz@mellanox.com>,
"David S. Miller" <davem@davemloft.net>,
John Fastabend <john.r.fastabend@intel.com>,
Linux Netdev List <netdev@vger.kernel.org>,
Amir Vadai <amirv@mellanox.com>, Tal Alon <talal@mellanox.com>,
Shani Michaeli <shanim@mellanox.com>
Subject: Re: [PATCH net-next 1/3] net/dcb: Add IEEE QCN attribute
Date: Thu, 05 Mar 2015 07:05:43 -0800 [thread overview]
Message-ID: <54F870C7.4030707@gmail.com> (raw)
In-Reply-To: <AM3PR05MB0935C9AF7EDFA7F90F3CAC6EDC1F0@AM3PR05MB0935.eurprd05.prod.outlook.com>
[...]
>>
>>> Looks good to me. Do you have a QCN enabled switch? I looked at
>>> implementing this awhile ago but didn't have any switch support so
>>> I never did it.
>>
>> I'l let Shachar to address the testing and the MIB questions.
>
> The Mellanox SwitchX-2 IC supports QCN. We were testing our NICs both
> with this switch IC and using internal test fixtures where we were
> injecting congestion notification messages as raw Ethernet packets by
> another host.
ah great didn't know that switch supported QCN.
>
>>
>>> Also do you have a user space client to configure this? I would like
>>> it if someone wanted to add support to lldpad/dcbtool.
>>
>> Sure, we have some netlink (python scripts) code to configure/read
>> this towards the kernel.
>>
>>
>>> [...]
[...]
>>>
>>>
>>> I'm assuming this structure maps to an IEEE MIB?
>>
>> yep, I guess so
>
> The structures map to the IEEE MIB for QCN (part of IEEE 802.1Qau).
> The fields rppp_max_rps and cndd_state_machine are in different sections
> than the rest of the fields. However, it seems bit redundant to define a
> whole struct just for one field. The cndd_state_machine is not explicitly
> defined in the MIB, as the LLDP negotiation, which the standard assumes,
> is implemented by lldpad.
>
>>
>>> Its a rather large structure for a single netlink type but this seems
>>> to be how we built
>>> the dcbnl interface and if it does seem logical that the structure is
>>> one logical block, meaning you need to supply all fields.
>>
>
> This is the set of parameters defining how you will reduce or increase you
> TX rate upon receiving CNM from the network. I agree that it is a long list,
> but this is how the standard was written...
yep works for me. I was just checking my assumptions are correct and
admittedly being a bit lazy so I didn't pull up the spec myself.
Thanks,
John
[...]
--
John Fastabend Intel Corporation
next prev parent reply other threads:[~2015-03-05 15:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-04 12:51 [PATCH net-next 0/3] Add QCN support to the DCB NL layer Or Gerlitz
2015-03-04 12:51 ` [PATCH net-next 1/3] net/dcb: Add IEEE QCN attribute Or Gerlitz
2015-03-04 17:19 ` John Fastabend
2015-03-05 6:53 ` Or Gerlitz
2015-03-05 9:21 ` Shachar Raindel
2015-03-05 15:05 ` John Fastabend [this message]
2015-03-04 12:51 ` [PATCH net-next 2/3] net/mlx4_core: Add basic elements for QCN Or Gerlitz
2015-03-04 12:51 ` [PATCH net-next 3/3] net/mlx4_en: Add QCN parameters and statistics handling Or Gerlitz
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