Re: [dpdk-users] What is TCP read performance by using DPDK?

[Pavel Vazharov <freakpv@gmail.com>]

Hi,

You can look at F-stack <https://github.com/F-Stack/f-stack/> or Seastar
<http://seastar.io/> for some performance measurements.
The first one uses the networking stack from FreeBSD 11, AFAIK. The second
one has their own networking stack. Both of them work over DPDK.

We also started with F-stack but later modified it to extract the DPDK code
out of it so that now we use a separate TCP stack per thread with shared
nothing design.
I can share with you our performance measurements with real traffic from an
ISP provider but they are not very relevant because we work in proxy mode,
not as a server.
However, our experience is roughly the following:
- for TCP (port 80) traffic the proxy over DPDK was about 1.5 times faster
than the same proxy working over standard Linux kernel. The application
layer was the same in both tests - a straightforward TCP proxy of port 80
traffic.
- we observed much bigger performance gain for UDP traffic where the
packets are more but smaller in our use case. Here we tested with UTP
(uTorrent Traffic Protocol). We have our own stack for UTP traffic
processing which works over UDP sockets and again we run the same
application code once over standard Linux  and over DPDK. The DPDK version
was able to handle the same amount of traffic on 2 cores with about 0.7%
packet losses as the Linux version handled on 8 cores with the same packet
losses. So, here we observed about 4 times improvement here.

However, take our measurements with a grain of salt because although the
application layer was the same for the Linux case we do some packet
inspection in the Linux kernel to filter out asymmetric TCP traffic, to
match UTP traffic, etc.
This filtration and matching was done in the DPDK layer of the new proxy so
the code under test was not 100% the same, more like 95% the same.
In addition to that, the UDP measurements were done on two separate
machines with the same type of CPUs and NICs but still they were two
separate machines.

Regards,
Pavel.