[ovs-dev] vhost-user invalid txqid cause discard of packets
Wang, Zhihong
zhihong.wang at intel.com
Thu Mar 3 15:24:13 UTC 2016
Hi,
I ran an OVS multiqueue test with very simple traffic topology, basically
2 ports each with 4 queues, 8 rxqs in total, like below:
Pktgen <=4q=> PHY <=4q=> OVS <=4q=> testpmd in the guest
First set pmd-cpu-mask to 8 cores, and everything works fine, each rxq
got a core, and all txqids are valid.
Then I set pmd-cpu-mask to 6 cores, and then 2 txqids become invalid in
__netdev_dpdk_vhost_send():
qid = vhost_dev->tx_q[qid % vhost_dev->real_n_txq].map;
qid returns -1 and this leads to discard of packets.
Consequently in testpmd in VM we see only 2 queues are working and
throughput drops more than a half.
It works again when I set pmd-cpu-mask to 4 cores.
My OVS and DPDK code are pulled from the repo on March 1st, 2016.
Let me know if you need more info to reproduce this issue.
Thanks
Zhihong
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