[lxc-devel] Poor bridging performance on 10 GbE

[Ryousei Takano]

Hi all,

I am evaluating the networking performance of lxc on 10 Gigabit Ethernet by
using netperf benchmark.
Using a macvlan device, the throughput was 9.6 Gbps. But, using a veth device,
the throughput was only 2.7 Gbps.
I think this is because the overhead of bridging devices is high.

I also checked the host OS's performance when I used a veth device.
I observed a strange phenomenon.

Before issuing lxc-start command, the throughput was 9.6 Gbps.
Here is the output of brctl show:
	$ brctl show
	bridge name	bridge id		STP enabled	interfaces
	br0		8000.0060dd470d49	no		eth1

After issuing lxc-start command, the throughput decreased to 3.2 Gbps.
Here is the output of brctl show:
	$ sudo brctl show
	bridge name	bridge id		STP enabled	interfaces
	br0		8000.0060dd470d49	no		eth1
								veth0_7573

I wonder why the performance is greatly influenced by adding a veth device
to a bridge device.

Here is my experimental setting:
	OS: Ubuntu server 8.10 amd64
	Kernel: 2.6.27-rc8 (checkout from the lxc git repository)
	Userland tool: 0.6.0
	NIC: Myricom Myri-10G

Any comments and suggestions will be appreciate.
If this list is not proper place to talk about this problem, can anyone tell me
the proper one?

Best regards,
Ryousei Takano