Bug 250436 - Regression in 12.stable em driver
Summary: Regression in 12.stable em driver
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: 12.1-STABLE
Hardware: amd64 Any
: --- Affects Only Me
Assignee: freebsd-net (Nobody)
Keywords: IntelNetworking, regression
Depends on:
Reported: 2020-10-18 14:27 UTC by Chris Collins
Modified: 2021-04-15 23:47 UTC (History)
1 user (show)

See Also:

smokeping data (342.25 KB, image/png)
2020-10-18 14:27 UTC, Chris Collins
no flags Details

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Description Chris Collins 2020-10-18 14:27:29 UTC
Created attachment 218861 [details]
smokeping data


I upgraded a server using the em driver from 11-STABLE to 12-STABLE 2 days ago.

I had previously tried EM_MULTIQUEUE but it behaved badly so was operating on single queue.

Since the update I am getting latency spikes, confirmed even on LAN.  I have smokeping graphs which show this if required, it was initially noticed by myself with lag in the ssh session which seems to come on for a couple of seconds and then disappears, but affects all traffic.

I observed that in 12-STABLE multiqueue now seems to be enforced, on other drivers such as igb there is a boot time tunable.

Is there a way to toggle multiqueue, or something else I can try to fix it, otherwise I am posting here a problem report.

I did also find this PR but has been closed.


Comment 1 Chris Collins 2020-10-18 14:31:09 UTC
Additional notes, it was yesterday I did the upgrade sorry, the graph improves during the dusk hours after I disabled LRO on the nic, but it didnt revert the previous behaviour just a improvement.
Comment 2 Kevin Bowling freebsd_committer 2021-04-15 23:47:57 UTC
(In reply to Chris Collins from comment #1)
Hi Chris,

I am interested in this report.  Can you try 12.2 or 13.0?  Can you provide some more info like an ifconfig, pciconf -lv and netstat -m?