From: Yong Wang <yongwang@vmware.com>
To: Thomas Monjalon <thomas@monjalon.net>,
Ferruh Yigit <ferruh.yigit@intel.com>
Cc: Chas Williams <3chas3@gmail.com>, Chas Williams <chas3@att.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"skhare@vmware.com" <skhare@vmware.com>,
"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] net/vmxnet3: keep link state consistent
Date: Wed, 18 Apr 2018 16:59:09 +0000 [thread overview]
Message-ID: <BY2PR05MB2359A63884519199D393C82AAFB60@BY2PR05MB2359.namprd05.prod.outlook.com> (raw)
In-Reply-To: <4064739.HSmrWIpKYf@xps>
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Thomas Monjalon
> Sent: Tuesday, April 17, 2018 1:24 PM
> To: Ferruh Yigit <ferruh.yigit@intel.com>
> Cc: Chas Williams <3chas3@gmail.com>; Chas Williams <chas3@att.com>;
> dev@dpdk.org; skhare@vmware.com; stable@dpdk.org
> Subject: Re: [dpdk-dev] [dpdk-stable] [PATCH] net/vmxnet3: keep link state
> consistent
>
> 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
> <thomas@monjalon.net> wrote:
> > >> 20/03/2018 15:12, Ferruh Yigit:
> > >>> On 3/18/2018 1:45 AM, Chas Williams wrote:
> > >>>> From: Chas Williams <chas3@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://urldefense.proofpoint.com/v2/url?u=https-
> 3A__dpdk.org_ml_archives_dev_2018-
> 2DApril_094696.html&d=DwICAg&c=uilaK90D4TOVoH58JNXRgQ&r=v4BBYIqi
> Dq552fkYnKKFBFyqvMXOR3UXSdFO2plFD1s&m=6ysGgXVpT4Dvp9bYO4DiAL
> 5HD_akgEyC0198WlWh8-0&s=zNjF-
> 3TX65mjvz8ONIeKuiZcPyXqt00aou26gUTXejQ&e=
> > >
> > > 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.
Yes and it makes sense for vmxnet3 to use ETH_LINK_FIXED.
> > >>>> Author: Thomas Monjalon <thomas@monjalon.net>
> > >>>> Date: Fri Jan 5 18:38:55 2018 +0100
> > >>>>
> > >>>> Fixes: 1e3a958f40b3 ("ethdev: fix link autonegotiation value")
> > >>>> Cc: stable@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
> > >>
> > >>
> > >>
> >
> >
>
>
>
>
next prev parent reply other threads:[~2018-04-18 16:59 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-18 1:45 [dpdk-stable] " Chas Williams
2018-03-20 14:12 ` Ferruh Yigit
2018-03-20 14:42 ` Chas Williams
2018-04-05 10:03 ` [dpdk-stable] [dpdk-dev] " Thomas Monjalon
2018-04-05 15:01 ` Chas Williams
2018-04-17 19:25 ` Ferruh Yigit
2018-04-17 20:24 ` Thomas Monjalon
2018-04-18 16:23 ` Ferruh Yigit
2018-04-18 16:59 ` Yong Wang [this message]
2018-04-20 0:10 ` [dpdk-stable] " Ferruh Yigit
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