[patch][lagg] - Set a better granularity and distribution on roundrobin protocol.

[Marcelo Araujo]

2014-06-24 6:54 GMT+08:00 Adrian Chadd <adrian at freebsd.org>:

> Hi,
>
> No, don't introduce out of order behaviour. Ever.


Yes, it has out of order behavior; with my patch much less. I upload two
pcap files and you can see by yourself, if you don't believe in what I'm
talking about.

Test done using: "iperf -s" and "iperf -c <ip> -i 1 -t 10".

1) Don't change the number of packets(default round robin behavior).
http://people.freebsd.org/~araujo/lagg/lagg-nop.cap
8 out of order packets.
Several SACKs.

2) Set the number of packets to 50.
http://people.freebsd.org/~araujo/lagg/lagg.cap
0 out of order packets.
Less SACKs.


> You may not think
> it's a problem for TCP, but UDP things and VPN things will start
> getting very angry. There are VPN configurations out there that will
> drop the VPN if frames are out of order.
>

I'm not thinking that will be a problem for TCP, but, in somehow it will
be, less throughput as I showed before, and less SACK. About the VPN,
please, tell me which softwares, and let me know where I can get a sample
to make a testbed.

However to be very honest, I don't believe anyone here when change
something at network protocols will make this extensive testbed. It is
almost impossible to predict what software it will works or not, and I
don't believe anyone here has all these stuff in hands.


>
> The ixgbe driver is setting the flowid to the msix queue ID, rather
> than a 32 bit unique flow id hash value for the flow. That makes it
> hard to do traffic distribution where the flowid is available.
>

Thanks for the explanation.


>
> There's an lagg option to re-hash the mbuf rather than rely on the
> flowid for outbound port choice - have you looked at using that? Did
> that make any difference?
>

Yes, I set to 0 the net.link.lagg.0.use _flowid, it make a little
difference to the default round robin implementation, but yet I can't reach
more than 5 Gbit/s. With my patch and set the packets to 50, it improved a
bit too.

So, thank you so much for all review, I don't know if you have time and a
testbed to make a real test, as I'm doing. I would be happy if you or more
people could make tests on that patch. Also, I have only ixgbe(4) to make
tests, would appreciate if this patch could be tested with other NICs too.

Best Regards,

-- 
Marcelo Araujo            (__)araujo at FreeBSD.org
\\\'',)http://www.FreeBSD.org <http://www.freebsd.org/>   \/  \ ^
Power To Server.         .\. /_)