[dpdk-dev] half packets dropped using l2fwd in VM

[dpdk-dev] half packets dropped using l2fwd in VM

[yuuko.nakase]

Hellow everyone,
I have a question regarding l2fwd in VM.

In my environment, about half of received packets are sent but
remaining half are dropped so I get Tx: 14.88Mpps Rx: 7.4Mpps rate
for 64 bytes packets at the traffic generator machine.

On the other hand, I get Tx: 14.88Mpps  Rx: 13.47Mpps using l2fwd
in Host machine only.

Something is wrong with my setting or that performance is no problem for
VM?
If there is a lack in my information, please let me know.

It will be a great help if anyone advise me!!

My environment is below.
Both case 1 and 2 get same result where rate is Tx: 14.88Mpps Rx: 7.4Mpps.

******

==Host machine
OS: Ubuntu 12.04
CPU: Xeon E5-2670  (8C/2.60GHz/20M)
RAM: 32GB
NIC: X520-DA2(dual port)
Kernel: 3.11.0
hugepages=1024, intel_iommu=on, iommu=pt, pci=assign-busses
qemu-kvm-0.14.0

[case1]
VF0 and VF2 belong to PF0
VF1 and VF3 belong to PF1
/usr/local/kvm/bin/qemu-system-x86_64 -hda ./vm1.img \
-m 4096 -cpu host -smp 4 -boot c -k ja -name m2_vm1 \
-monitor telnet::4444,server,nowait -vnc :1 -daemonize \
-device pci-assign,host=02:10.0 \
-device pci-assign,host=02:10.1 \
-device pci-assign,host=02:10.2 \
-device pci-assign,host=02:10.3

[case1]
VF0 belong to PF0
VF1 belong to PF1
/usr/local/kvm/bin/qemu-system-x86_64 -hda ./vm1.img \
-m 4096 -cpu host -smp 4 -boot c -k ja -name m2_vm1 \
-monitor telnet::4444,server,nowait -vnc :1 -daemonize \
-device pci-assign,host=02:10.0 \
-device pci-assign,host=02:10.1

==Virtual machine
OS: Ubuntu 12.04
Kernel: 3.11.0
DPDK: 1.6.0

[case1]
l2fwd -c f -n 4 -- -q 1 -p 0x3

[case2]
l2fwd -c 3 -n 4 -- -q 1 -p 0x3

==Traffic generator machine
Pktgen-DPDK
pktgen>set mac 0 <MAC addr of VM's connected port>
pktgen>start 0

******


Regards,
nks