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From: "Benoit Ganne (bganne)" <bganne@cisco.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: "users@dpdk.org" <users@dpdk.org>
Subject: Re: [dpdk-users] CX4-Lx VF link status in Azure
Date: Thu, 26 Mar 2020 14:26:56 +0000
Message-ID: <CH2PR11MB4327C92B0AF7B4B6E1DEAA69C1CF0@CH2PR11MB4327.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20200325154815.13fc7a4e@hermes.lan>

Hi Stephen,

> Is this with netvsc PMD or failsafe PMD?

I am using failsafe PMD using the string "--vdev net_vdev_netvsc0,iface=eth1" etc. as mentioned here: https://docs.microsoft.com/en-us/azure/virtual-network/setup-dpdk
I checked with gdb what are the underlying devices and there is 1 mlx5 and 1 tap instance as expected.
To get the link state, the call stack is rte_eth_link_get_nowait() -> fs_link_update() -> mlx5_link_update() -> mlx5_link_update_unlocked_gs() which looks good to me.
The link state update fails in mlx5_link_update_unlocked_gs() because the link speed retrieved from the Linux kernel driver is '0' (unknown). Note that ethtool and '/sys/class/net/<iface>/speed' also fails to report the link speed (but not the link status).
At the end of the day, maybe the Linux kernel driver should report a link speed, however I think it should not prevent DPDK to update the link state (up/down). 
Just removing the offending test makes everything working again but I do not think it is the correct solution: I do not know why this test was added for.

> You maybe missing this patch, which is only in current development branch.
> Since it is tagged for stable, it should end up in later LTS versions as
> well 18.11.X and 19.11.X.

I tried the patch but it did not solve the issue. I think it is expected as I am using failsafe with tap and not netvsc, correct?


  reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25 19:07 Benoit Ganne (bganne)
2020-03-25 21:32 ` Stephen Hemminger
2020-03-25 22:48 ` Stephen Hemminger
2020-03-26 14:26   ` Benoit Ganne (bganne) [this message]
2020-03-26 17:57     ` Stephen Hemminger
2020-03-26 18:27       ` Benoit Ganne (bganne)
2020-03-26 18:52         ` Thomas Monjalon
2020-03-26 19:00           ` Benoit Ganne (bganne)
2020-03-26 20:09             ` Mark Bloch
2020-03-26 20:40               ` Thomas Monjalon
2020-03-26 21:31                 ` Thomas Monjalon
2020-03-27 10:02                   ` Benoit Ganne (bganne)
2020-03-27 10:13                     ` Thomas Monjalon
2020-03-27 17:26                       ` Benoit Ganne (bganne)
2020-03-27 22:34                         ` Thomas Monjalon

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