[dpdk-users] Can't get line-rate with l3fwd

Сергей Львов log0div0 at gmail.com
Tue May 17 23:48:50 CEST 2016


I have two traffic generators (pktgen) and a router (l3fwd) in between. The
traffic generators are connected with the router via 10Gb links.

generato #1 <--10Gb full duplex--> router <--10Gb full duplex--> generator

Both generator send 64-bytes packets at full 10Gb rate.

The problem is that l3fwd recieves only 7.5Gb/s on each port. I'd run
pktgen instead of l3fwd and had the same result.

If there's only one generator sending packets (10 Gb/s) and another is
turned off, l3fwd can recieve all the packets (10 Gb/s)

I figured out that the rte_eth_rx_burst function returns 0 quite often.
This could mean that the problem is not in CPU.

Is it possible to increase performance up to 20Gb/s or is there a hardware
limit? I'd read the dpdk articles "How to get best performance with NICs on
Intel platforms" and "IXGBE Driver", but it didn't help.

The hardware is:
- Intel(R) 82599EB 10 Gigabit Ethernet Controller
- Intel(R) Xeon(R) CPU E5-2470 v2 @ 2.40GHz
- PCI Express bandwidth of 32GT/s (Speed:5.0GT/s, Width: x8, Encoding

Memory: 8 hugepages x 1Gb

The command is:
./build/l3fwd -c 0xf0000 -n 4 — -p 0x3 —config="(0,0,19),(1,0,18)"

Any ideas how to resolve the perfomance issure will be appreciated.


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