Re: DPDK testpmd forwarding performace degradation

[Stephen Hemminger <stephen-OTpzqLSitTUnbdJkjeBofR2eb7JE58TQ@public.gmane.org>]

On Mon, 26 Jan 2015 13:17:48 +0300
Alexander Belyakov <abelyako-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

> Hello,
> 
> recently I have found a case of significant performance degradation for our
> application (built on top of DPDK, of course). Surprisingly, similar issue
> is easily reproduced with default testpmd.
> 
> To show the case we need simple IPv4 UDP flood with variable UDP payload
> size. Saying "packet length" below I mean: Eth header length (14 bytes) +
> IPv4 header length (20 bytes) + UPD header length (8 bytes) + UDP payload
> length (variable) + CRC (4 bytes). Source IP addresses and ports are selected
> randomly for each packet.
> 
> I have used DPDK with revisions 1.6.0r2 and 1.7.1. Both show the same issue.
> 
> Follow "Quick start" guide (http://dpdk.org/doc/quick-start) to build and
> run testpmd. Enable testpmd forwarding ("start" command).
> 
> Table below shows measured forwarding performance depending on packet
> length:
> 
> No. -- UDP payload length (bytes) -- Packet length (bytes) -- Forwarding
> performance (Mpps) -- Expected theoretical performance (Mpps)

Did you try using git bisect to identify the problem.