OK so this is bat guano...
Boot off Fedora-Workstation-Live-x86_64-Rawhide-20170110.n.0.iso USB
stick and retest:
[root@localhost liveuser]# iperf -c 10.0.0.3
------------------------------------------------------------
Client connecting to 10.0.0.3, TCP port 5001
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[ 3] local 10.0.0.4 port 45208 connected with 10.0.0.3 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 70.8 MBytes 59.2 Mbits/sec
For reference the previous result on Fedora 25 with kernel 4.8.17 was:
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.4 sec 35.4 MBytes 28.5 Mbits/sec
I retested Fedora 25 to match the same kernel used by Rawhide, and I get:
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.1 sec 49.9 MBytes 41.6 Mbits/sec
Firmware versions are the same in all three cases. And the iw outputs
are all the same. And the laptop is in the same location. So there is
something in the ether affecting the result, but it does seem pretty
clear there's something awry with Fedora 25 and it's not the kernel or
the firmware. Maybe wpa_supplicant? OK this is weird....
wpa_supplicant-2.5-5.fc24.x86_64
When I check koji, there are newer versions available for some time.
wpa_supplicant-2.6-1.fc25 lkundrak 2016-11-23 12:12:48
That's listed as being in updates-testing for 2 months.
https://bodhi.fedoraproject.org/updates/?packages=wpa_supplicant
OK so update to that and reboot...
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 48.4 MBytes 40.5 Mbits/sec
Nope. Maybe it's a NetworkManager issue? I can't really update that,
or at least, I'm not willing to mix Rawhide's Network Manager on F25.
Chris