[ovs-discuss] TSO not working for VM iperf data packets.

Piyush R Srivastava1 pirsriva at in.ibm.com
Sat Dec 19 10:10:23 UTC 2015


HI Jesse,

Oh yeah i cross checked that... I'm sorry for the mixup

The port whose tcpdump i have put up is the egress port of router namespace
We see offloaded packets on both ingress / egress ports of router
namespaces. So within router namespace we do see OFFLOADED packets

The  only thing between the egress router namespace port and the uplink
(eth1) is BR-EX ( OVS External Bridge ). Both are mapped to same bridge

[root at rhel7-23 ~]# ovs-vsctl show
7f2dc796-5e5c-4e73-b976-43b953b7255c
    Bridge br-ex
        Port br-ex
            Interface br-ex
                type: internal
        Port "eth1"
            Interface "eth1"
        Port "qg-ab10ec1d-2b"
            Interface "qg-ab10ec1d-2b"
                type: internal


Here is the ethtool details for BR-EX

[root at rhel7-23 ~]# ethtool -k br-ex
Features for br-ex:
rx-checksumming: off [fixed]
tx-checksumming: on				<< TX-Checksumming ON
        tx-checksum-ipv4: off [fixed]			<<TX-checksum-ipv4
OFF
        tx-checksum-ip-generic: on
        tx-checksum-ipv6: off [fixed]
        tx-checksum-fcoe-crc: off [fixed]
        tx-checksum-sctp: off [fixed]
scatter-gather: on
        tx-scatter-gather: on
        tx-scatter-gather-fraglist: on
tcp-segmentation-offload: on			<< TSO ON
        tx-tcp-segmentation: on
        tx-tcp-ecn-segmentation: on
        tx-tcp6-segmentation: on
udp-fragmentation-offload: on
generic-segmentation-offload: on
generic-receive-offload: on
large-receive-offload: off [fixed]
rx-vlan-offload: off [fixed]
tx-vlan-offload: on
ntuple-filters: off [fixed]
receive-hashing: off [fixed]
highdma: on
rx-vlan-filter: off [fixed]
vlan-challenged: off [fixed]
tx-lockless: on [fixed]
netns-local: off [fixed]
tx-gso-robust: off [fixed]
tx-fcoe-segmentation: off [fixed]
tx-gre-segmentation: on
tx-ipip-segmentation: on
tx-sit-segmentation: on
tx-udp_tnl-segmentation: on
tx-mpls-segmentation: on
fcoe-mtu: off [fixed]
tx-nocache-copy: on
loopback: off [fixed]
rx-fcs: off [fixed]
rx-all: off [fixed]
tx-vlan-stag-hw-insert: off [fixed]
rx-vlan-stag-hw-parse: off [fixed]
rx-vlan-stag-filter: off [fixed]
busy-poll: off [fixed]


I see that TSO is ON but tx-checksum-ipv4: off [fixed] for tx-checksumming.
Does this have any effect of TSO?

Thanks and regards,
Piyush Raman




From:	Jesse Gross <jesse at kernel.org>
To:	Piyush R Srivastava1/India/IBM at IBMIN
Cc:	discuss at openvswitch.org, Gowtham Narasimhaiah/India/IBM at IBMIN,
            Mala Anand <manand at us.ibm.com>
Date:	12/19/2015 02:09 AM
Subject:	Re: [ovs-discuss] TSO not working for VM iperf data packets.



On Fri, Dec 18, 2015 at 12:25 PM, Piyush R Srivastava1 <pirsriva at in.ibm.com
> wrote:
  Hi Jesse,

  Yeah that was the tcpdump for ingress port.
  Kindly find the tcpdump for egress port in namespace as well-


  [root at rhel7-23 ~]# ip netns exec
  qrouter-223d91ae-3025-4070-83d0-63faa58d819b tcpdump -ennqi
  qg-ab10ec1d-2b -c 30 host 1.1.1.34
  tcpdump: verbose output suppressed, use -v or -vv for full protocol
  decode
  listening on qg-ab10ec1d-2b, link-type EN10MB (Ethernet), capture size
  65535 bytes


 This has the same name as the interface as you showed before, so I'm not
sure which is right. However, I would look at each interface in the path
and try to pinpoint where TSO stops occurring. There's not much more that I
can suggest.

  Both the egress port of Namespace and physical NIC for external network
  (eth1) are mapped to BR-EX, however, BR-EX has 1500 MTU.
  Do you think that is affecting, even with TSO ON for eth1?


The MTU should not matter if TSO is set. However, TSO needs to be set on
all interfaces, not just the egress Ethernet interface.


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