On 4/5/2018 4:01 PM, Chas Williams wrote:
> On Thu, Apr 5, 2018 at 6:03 AM, Thomas Monjalon <tho...@monjalon.net> wrote:
>> 20/03/2018 15:12, Ferruh Yigit:
>>> On 3/18/2018 1:45 AM, Chas Williams wrote:
>>>> From: Chas Williams <ch...@att.com>
>>>>
>>>> The vmxnet3 never attempts link speed negotiation. As a virtual device
>>>> the link speed is vague at best. However, it is important for certain
>>>> applications, like bonding, to see a consistent link_status. 802.3ad
>>>> requires that only links of the same cost (link speed) be enslaved.
>>>> Keeping the link status consistent in vmxnet3 avoids races with bonding
>>>> enslavement.
>>
>> I don't understand the issue.
>> Are you sure it is not an issue in bonding?
>
> 802.3ad "requires" you to bond together links of the same speed and duplex.
> The
> primary reason for this (or so I gather) is to ensure that the
> spanning-tree cost for
> each port is the same. If you fail from one link to another, you
> don't want a spanning
> tree reconfiguration.
>
> The problem exists in general for most of the PMDs -- see
> https://dpdk.org/ml/archives/dev/2018-April/094696.html
>
> The problem is more vexing for AUTONEG and bonding. I am still thinking about
> that. You don't know until you go to activate the slave and bonding
> only makes its
> check during the setup phase. So for virtual adapters and bonding, not using
> AUTONEG makes more sense because it is just easier to handle.
>
>>
>> About the right value to set for virtual PMDs, I don't know, both are fakes.
>> I thought that AUTONEG better convey the vague link speed you describe.
>
> It's not vague. There is no negotiation of any sort. The link speed
> (and therefore cost)
> of the link is fixed. While the particular rate you get from the
> adapter depends
> on a number of factors, the link speed isn't going to change. The
> adapter is not
> going to change the link speed from 10G to 1G or change from full duplex to
> half
> duplex.
Hi Chas, Thomas,
What is the latest status of this patch? Is it agreed to convert link_autoneg to
ETH_LINK_FIXED for following PMDs [1]?
[1]
pcap
softnic
vmxnet3
>
>>
>>
>>>> Author: Thomas Monjalon <tho...@monjalon.net>
>>>> Date: Fri Jan 5 18:38:55 2018 +0100
>>>>
>>>> Fixes: 1e3a958f40b3 ("ethdev: fix link autonegotiation value")
>>>> Cc: sta...@dpdk.org
>>>
>>> There were a few more PMDs [1] they have been updated from FIXED to AUTONEG
>>> with
>>> above commit, do you think should we update them back to FIXED as well?
>>>
>>> [1]
>>> pcap
>>> softnic
>>> vmxnet3
>>
>> Yes, they all can be fixed/LINK_FIXED :) I guess
>>
>>
>>
