17/04/2018 21:25, Ferruh Yigit:
> 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
Yes, OK for ETH_LINK_FIXED.
> >>>> 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
> >>
> >>
> >>
>
>
