[dpdk-dev] e1000: randomly loosing link change events triggered by the peer

[Lu, Wenzhuo]

Hi Marc,

From: marc.sune at gmail.com [mailto:marc.sune at gmail.com] On Behalf Of Marc
Sent: Monday, March 28, 2016 7:03 PM
To: Lu, Wenzhuo
Cc: dev at dpdk.org
Subject: Re: e1000: randomly loosing link change events triggered by the peer



On 28 March 2016 at 03:54, Lu, Wenzhuo <wenzhuo.lu at intel.com<mailto:wenzhuo.lu at intel.com>> wrote:
Hi Marc

From: Marc Sune [mailto:marcdevel at gmail.com<mailto:marcdevel at gmail.com>]
Sent: Saturday, March 26, 2016 9:43 AM
To: dev at dpdk.org<mailto:dev at dpdk.org>; Lu, Wenzhuo
Subject: e1000: randomly loosing link change events triggered by the peer

I found that in the current HEAD in master testing it with an I218-LM in autoneg mode, when link is forced to be renegociated by the peer (e.g. via ethtool on a peer Linux box) _some_ change events are lost.

It is quite random, but it seems to happen more while changing the speed than when changing the duplex mode.

However, when one or more link change events have been lost and the phy medium is disconnected and reconnected, the link speed and duplex mode are then correctly updated.

Marc

[Wenzhuo] Thanks for let us know this issue. May I ask some questions? Do you mean this NIC 0x155A?

0x15A2,  I218-LM (rev 03)

EAL: PCI device 0000:00:19.0 on NUMA socket -1
EAL:   probe driver: 8086:15a2 rte_em_pmd
EAL:   PCI memory mapped at 0x7f85cf400000
EAL:   PCI memory mapped at 0x7f85cf420000
PMD: eth_em_dev_init(): port_id 0 vendorID=0x8086 deviceID=0x15a2

I think this is not a NIC issue, but a general problem of the driver (or em code).
[Wenzhuo] I don’t have a 15a2 on hand. I’m using i350. I haven’t hit the same problem.  As you said it’s random. Would you like to let me know why you think it’s general not NIC specific? Thanks.

About how to reproduce this problem, you mean use these CLIs, ethtool –s xxx advertise xxx, ethtool –s xxx duplex half/full, to change the peer port’s configuration?

Correct. I modified l2fwd to check link status and print it on each port stats print iteration. Then from the peer I modified the link properties via ethtool.
[Wenzhuo] Would you like to give me a patch of your change? Thanks.

The result is that transitions from autoneg speeds and/or duplex mode settings are randomly not detected (rte_eth_link in rte_eth_dev_data is not updated), and it prints not-up-to-date state.

Marc