Bug 200026 - [vmware] em driver reports "Watchdog timeout -- resetting" on vmware ESXi
Summary: [vmware] em driver reports "Watchdog timeout -- resetting" on vmware ESXi
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: 10.1-RELEASE
Hardware: amd64 Any
: --- Affects Some People
Assignee: freebsd-emulation mailing list
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-05-07 12:43 UTC by Nick Hilliard
Modified: 2015-07-08 15:18 UTC (History)
1 user (show)

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Description Nick Hilliard 2015-05-07 12:43:50 UTC
the freebsd em driver periodically hangs when running in a VM on all versions of esxi after (but not including) build 799733 (ESXi 5.0 GA).  The symptoms of the problem are that the freebsd vm drops traffic on the affected interface for a period of time.  The kernel reports errors:

Apr 22 19:12:08 xxxx kernel: em0: Watchdog timeout -- resetting
Apr 25 07:38:18 xxxx kernel: em0: Watchdog timeout -- resetting
Apr 27 23:29:35 xxxx kernel: em1: Watchdog timeout -- resetting
Apr 29 18:03:29 xxxx kernel: em1: Watchdog timeout -- resetting
May  5 05:28:38 xxxx kernel: em1: Watchdog timeout -- resetting

FreeBSD 8/9 were particularly badly affected by this, to the point that the em driver was totally unusable on those versions when running as vm after esxi build 799733, i.e ~30% packet loss for pings.  The intel em driver update in 10.0 helped quite a bit, and anecdotally the problem seems to be less bad on ESXi 6.0.  Now the figure seems to be down at around 1-2% pktloss over extended periods of time.

However it's still there on 10.1 with all recent versions of esxi, and prevents freebsd from being able to function properly as a router when using the em interface.

The problem also affects freebsd derivatives (e.g. some versions of JunOS Firefly / vRR / vMX, etc).