[ovs-dev] vlan tag add/remove affect bandwidth a lot

[Li, Chen]

Sorry, I’m really new to OVS, can you give me more specific move I can do next?
I’m eager to solve this ,but really have no idea where to start……☹

From: Jesse Gross [mailto:jesse at nicira.com]
Sent: Saturday, October 19, 2013 12:16 AM
To: Li, Chen
Cc: dev at openvswitch.org
Subject: Re: [ovs-dev] vlan tag add/remove affect bandwidth a lot

On Fri, Oct 18, 2013 at 12:08 AM, Li, Chen <chen.li at intel.com<mailto:chen.li at intel.com>> wrote:
I have changed my test method a little to make the issue more clear:
[cid:image001.png at 01CECD05.65096C50]

As you can see, my vm has two virtual NIC, tap1 is working under VLAN (tag=2002), while tap2 is working under FLAT.
And the bandwidth is :
Test Node => tap1   2.85 Gbits/sec
Test Node => tap2   9.40 Gbits/sec

Flows rules applied:
ovs-ofctl dump-flows br-int
NXST_FLOW reply (xid=0x4):
cookie=0x0, duration=2024.067s, table=0, n_packets=989820, n_bytes=23566560107, idle_age=1, priority=3,in_port=16,vlan_tci=0x0000 actions=mod_vlan_vid:2,NORMAL
cookie=0x0, duration=2024.769s, table=0, n_packets=4873950, n_bytes=7378336782, idle_age=20, priority=3,in_port=17,dl_vlan=2002 actions=mod_vlan_vid:1,NORMAL
cookie=0x0, duration=2029.604s, table=0, n_packets=52, n_bytes=3768, idle_age=72, priority=2,in_port=16 actions=drop
cookie=0x0, duration=2027.391s, table=0, n_packets=4729, n_bytes=286686, idle_age=1, priority=2,in_port=17 actions=drop
cookie=0x0, duration=2031.156s, table=0, n_packets=3161368, n_bytes=208726297, idle_age=20, priority=1 actions=NORMAL

ovs-ofctl dump-flows br-eth4
NXST_FLOW reply (xid=0x4):
cookie=0x0, duration=2043.307s, table=0, n_packets=925503, n_bytes=61092489, idle_age=90, priority=4,in_port=7,dl_vlan=2 actions=strip_vlan,NORMAL
cookie=0x0, duration=2048.566s, table=0, n_packets=47, n_bytes=3212, idle_age=91, priority=2,in_port=7 actions=drop
cookie=0x0, duration=2049.988s, table=0, n_packets=989979, n_bytes=23566580239, idle_age=1, priority=1 actions=NORMAL

ovs-ofctl dump-flows br-eth5
NXST_FLOW reply (xid=0x4):
cookie=0x0, duration=2047.936s, table=0, n_packets=2235861, n_bytes=147635900, idle_age=43, priority=4,in_port=4,dl_vlan=1 actions=mod_vlan_vid:2002,NORMAL
cookie=0x0, duration=2050.289s, table=0, n_packets=4784, n_bytes=293458, idle_age=1, priority=2,in_port=4 actions=drop
cookie=0x0, duration=2051.95s, table=0, n_packets=305743, n_bytes=7076819244, idle_age=1, priority=1 actions=NORMAL

Both path has an adding and stripping of VLAN tags operation, so where can I find the difference from code ??

The problem is almost certainly not the actual modification of tags but in the interactions with the rest of the system. In that case, it's not surprising that rewriting the tags doesn't change anything.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openvswitch.org/pipermail/ovs-dev/attachments/20131019/c0e7ec92/attachment-0003.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.png
Type: image/png
Size: 8093 bytes
Desc: image001.png
URL: <http://mail.openvswitch.org/pipermail/ovs-dev/attachments/20131019/c0e7ec92/attachment-0005.png>