From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [dpdk-stable] [PATCH] net/vmxnet3: keep link state consistent Date: Tue, 17 Apr 2018 22:24:14 +0200 Message-ID: <4064739.HSmrWIpKYf@xps> References: <20180318014552.16703-1-3chas3@gmail.com> <7001889b-9a98-c353-ad9c-207bffc6869a@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: Chas Williams <3chas3@gmail.com>, Chas Williams , dev@dpdk.org, skhare@vmware.com, stable@dpdk.org To: Ferruh Yigit Return-path: In-Reply-To: <7001889b-9a98-c353-ad9c-207bffc6869a@intel.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 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 wrote: > >> 20/03/2018 15:12, Ferruh Yigit: > >>> On 3/18/2018 1:45 AM, Chas Williams wrote: > >>>> From: Chas Williams > >>>> > >>>> 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 > >>>> 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 > >> > >> > >> > >