[SOLVED] performance issue within VNET jail

[Michael Grimm]

Hi,

let me come back to this issue I did report end of last year: https://lists.freebsd.org/pipermail/freebsd-net/2017-December/049470.html

My setup:

	vtnet/pf-NAT <—> epairXa (bridge0) epairXb <-> vnet jail

My observations regarding a sample download like "wget https://download.freebsd.org/ftp/releases/ISO-IMAGES/11.1/FreeBSD-11.1-RELEASE-amd64-bootonly.iso -O /dev/null"

	(-) expected performance at the host of about 30 MB/s
	(-) dramatic loss of performance inside a vnet jail down to about 80 KB/s

My solution:

	adding 'hw.vtnet.lro_disable="1"' to /boot/loader.conf

In the meantime I did find a comparable reference regarding Linux: 

	"Previously, network drivers that had Large Receive Offload (LRO) enabled by default caused the system to run slow, 
	lose frame, and eventually prevent communication, when using software bridging. With this update, LRO is automatically 
	disabled by the kernel on systems with a bridged configuration, thus preventing this bug."

	https://bugzilla.redhat.com/show_bug.cgi?id=772317


I do not have the knowledge to judge if that should be disabled in FreeBSD as well when software bridging is involved, thus I just want to let you know. 
(And that's the reason that I have included the author of the vnet driver in CC.)

With kind regards,
Michael