em0@pci0:0:25:0: class=0x020000 card=0xe0001458 chip=0x153b8086 rev=0x04 hdr=0x00
vendor = 'Intel Corporation'
device = 'Ethernet Connection I217-V'
class = network
subclass = ethernet
Network lag when using this interface with ssh. SMB share are unusable on this nic.
Quick network trace reveal a lot of DUP ack and retransmit.
With a re0 nic, system go well.
How-To-Repeat: Use a I217-V chipset as nic and do some ssh keying or use samba.
Over to maintainer(s).
I see this on my laptop prior to the watchdog improvements to em(4) in current and 10/stable. Can you retest?
I second this. I have tested this NIC with pinging and find that it is dropping packets when running in 100M full and half duplex. Variety of em-related settings have been tried to no avail. I will follow up with a lag report for when running with no packet loss (1000M).
(In reply to Damien from comment #3)
I can confirm that when the NIC is running at 1000M Full-Duplex, ssh shows no lag unlike that exhibited at 100M. On this exact same machine, Linux runs the NIC at 100M with no degradation in performance/lost packets. Suggest that this is an issue with the em driver itself. I have validated this against FreeBSD 10.2 and 11 (CURRENT).
(In reply to Sean Bruno from comment #2)
Sean, there's supposed to be a fix in the i219/Skylake support patch that always disables TSO at non-1G speeds. Would that help in this case?
(In reply to Eric Joyner from comment #5)
I can totally test this out, however I don't think the original bug report had anything to do with gigabit vs 100mbit.
(In reply to Sean Bruno from comment #6)
Oh yeah, I didn't notice Damien wasn't the OP. It'd be nice to get more info from cg.
I will clarify:
I had the same ssh login and input lag. I also noticed some NFS lag. I investigated and found some lost packets (around 20%). I connected the FreeBSD box directly to another that supports 1Gbps as opposed to the 100Mbps router that it was connected to. I noticed that there were no dropped packets. I then set the NIC to 100Mbps and began to see packet loss again as it was with the router setup before.
I added these comments because my troubleshooting may assist in identifying that there is a problem with the em driver. I have confirmed this by downloading, compiling, and testing the latest em driver from Intel.
I am hoping that the networking team can investigate lost packets at 100 Mbps for the I217-V NIC and replicate the above troubleshooting steps, and hopefully get a resolution rather than the workaround that I have presently implemented.
(In reply to Damien from comment #8)
We are currently investigating this and hope to have a fix soon.
For bugs that match the following
- Status Is In progress
- Untouched since 2018-01-01.
- Affects Base System OR Documentation
Reset to open status.
I did a quick pass but if you are getting this email it might be worthwhile to double check to see if this bug ought to be closed.