Re: [PATCH bpf-next 00/15] Introducing AF_XDP support

[Jason Wang <jasowang@redhat.com>]

On 2018年04月24日 16:44, Magnus Karlsson wrote:
>>> We have run some benchmarks on a dual socket system with two Broadwell
>>> E5 2660 @ 2.0 GHz with hyperthreading turned off. Each socket has 14
>>> cores which gives a total of 28, but only two cores are used in these
>>> experiments. One for TR/RX and one for the user space application. The
>>> memory is DDR4 @ 2133 MT/s (1067 MHz) and the size of each DIMM is
>>> 8192MB and with 8 of those DIMMs in the system we have 64 GB of total
>>> memory. The compiler used is gcc version 5.4.0 20160609. The NIC is an
>>> Intel I40E 40Gbit/s using the i40e driver.
>>>
>>> Below are the results in Mpps of the I40E NIC benchmark runs for 64
>>> and 1500 byte packets, generated by commercial packet generator HW that is
>>> generating packets at full 40 Gbit/s line rate.
>>>
>>> AF_XDP performance 64 byte packets. Results from RFC V2 in parenthesis.
>>> Benchmark   XDP_SKB   XDP_DRV
>>> rxdrop       2.9(3.0)   9.4(9.3)
>>> txpush       2.5(2.2)   NA*
>>> l2fwd        1.9(1.7)   2.4(2.4) (TX using XDP_SKB in both cases)
>> This number looks not very exciting. I can get ~3Mpps when using testpmd in
>> a guest with xdp_redirect.sh on host between ixgbe and TAP/vhost. I believe
>> we can even better performance without virt. It would be interesting to
>> compare this performance with e.g testpmd + virito_user(vhost_kernel) + XDP.
> Note that all the XDP_SKB numbers plus the TX part of XDP_DRV for l2fwd
> uses SKBs and the generic XDP path in the kernel. I am not surprised those
> numbers are lower than what you are seeing with XDP_DRV support.
> (If that is what you are running? Unsure about your setup).

Yes, I'm using haswell E5-2630 v3 @ 2.40GHz and ixgbe.

>   The
> 9.4 Mpps for RX is what you get with the XDP_DRV support and copies
> out to user space. Or is it this number you think is low?

No rxdrop looks ok. I mean for l2fwd only.

>   Zerocopy will be added
> in later patch sets.
>
> With that said, both XDP_SKB and XDP_DRV can be optimized. We
> have not spent that much time on optimizations at this point.
>

Yes, and it is interesting to compare the performance numbers between 
AF_XDP and TAP XDP + vhost_net since their functions are almost equivalent.

Thanks