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

[Reid Price]

Hi chen,

What Jesse is pointing out is that your problem seems unrelated to OVS.  In
particular, the low throughput you observe is probably related to something
else in the system, be it drivers, VLAN offloading, intermediate network,
etc.

The point is that you already have verified for yourself that the actions
don't really have an impact, especially compared to the effect when the
traffic is ultimately tagged =)

  -Reid


On Sat, Oct 19, 2013 at 4:57 AM, Li, Chen <chen.li at intel.com> wrote:

>  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……L****
>
> ** **
>
> *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> wrote:****
>
>  I have changed my test method a little to make the issue more clear:****
>
> ****
>
>  ****
>
> 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.****
>
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>
>
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