[Bug 215737] [bhyve] utilizing virtio-net truncates jumbo frames at 4084 bytes length

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=215737

--- Comment #13 from Harald Schmalzbauer <bugzilla.freebsd at omnilan.de> ---
(In reply to P Kern from comment #12)

In case you end up switching from "vmxnet3"/[vmx(4)|vmx3f(4)] to
"e1000"/[em(4)], depending on your workload, you can save lots of overhead if
you switch to "e1000e" instead, since it utilizes MSI(-X).
To make use of, you need to set 'hw.pci.honor_msi_blacklist=0' in loader.conf.

And then, there's a negotiaten mismatch between FreeBSD/ESXi (ESX is selecting
MSI while FreeBSD MSI-X – as far as I remember).  You can circumvent by simply
re-loading the kernel module!  "e1000e"/[if_em(4)] works fine in MSI-X mode.

Since FreeBSD-11, there's also devctl(8), which could take care of the driver
re-initialization, but when I wrote my rc(8) script to automatically re-load
kernel modules on ESXi guests, it was not available.
Happy to share the rc(8) script on request.

-harry

-- 
You are receiving this mail because:
You are the assignee for the bug.