Tool udp_sink test recvfrom should request the source address

[netoptimizer]

The recvfrom test in udp_sink is probably identical to recv, because as it doesn't request the source address.

Based on discussion:
https://lore.kernel.org/netdev/b71441bb2fa14bc7b583de643a1ccf8b@AcuMS.aculab.com

From: Jesper Dangaard Brouer - Sent: 28 November 2019 11:12
...

Can you test recv() as well?

Sure: 9e3c8b86a2d662

$ sudo taskset -c 1 ./udp_sink --port 9  --count $((10**6*2))
           	run      count   	ns/pkt	pps		cycles	payload
recvMmsg/32  	run:  0	 2000000	653.29	1530704.29	2351	18	 demux:1
recvmsg   	run:  0	 2000000	631.01	1584760.06	2271	18	 demux:1
read      	run:  0	 2000000	582.24	1717518.16	2096	18	 demux:1
recvfrom  	run:  0	 2000000	547.26	1827269.12	1970	18	 demux:1
recv      	run:  0	 2000000	547.37	1826930.39	1970	18	 demux:1

I think it might be faster than read().

Slightly, but same speed as recvfrom.

From: David Laight David.Laight@ACULAB.COM

I notice that you recvfrom() code doesn't request the source address.
So is probably identical to recv().