Intel wireless 6300 ultimate, regression of throughput 12.04 >> 16.04

[H.i.M]

I submitted a new bug report as the bug #1471794 has a slightly different hardware.

I wanted to migrate from Ubuntu 12.04.04 LTS to 16.04 and installed a new Ubuntu 16.04 LTS on a second SSD for testing on the same hardware. I was not moving my laptop in space during the testing. Both tests were performed on battery on 5GHZ wifi connected to a AVM Fritzbox 7490 router. Ubuntu 12.04.04 showed a throughput of about 180Mbit/s. Ubuntu 16.04 showed only about 60Mbit/s.

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Ubuntu 16.04

iperf -c 192.168.10.11 -r -t 30
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.10.11, TCP port 5001
TCP window size: 136 KByte (default)
------------------------------------------------------------
[ 5] local 192.168.10.21 port 39466 connected with 192.168.10.11 port 5001
[ ID] Interval Transfer Bandwidth
[ 5] 0.0-30.1 sec 125 MBytes 34.8 Mbits/sec
[ 4] local 192.168.10.21 port 5001 connected with 192.168.10.11 port 60995
[ 4] 0.0-30.2 sec 206 MBytes 57.1 Mbits/sec

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Complete system:
Dell Latitude E6400, RAM 4GB, CPU Intel E8400, Network controller: Intel Corporation Centrino Ultimate-N 6300

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What is the full computer model number (ex. HP G32-301TX Notebook PC)?
Dell Latitude E6400 Notebook, newest Bios A34

If you update your BIOS to the newest version following the guide here, does this change anything?
Already newest BIOS installed

Regarding your wireless Access Point (AP):
3a. What is the current AP manufacturer, full model, revision, and firmware version?
AVM, Fritzbox 7490, v1, FRITZ!OS:06.51

3b. If you update the AP to the latest firmware does it change anything?
Already newest firmware installed.

3c. What wireless connection type are you using (802.11ac, 802.11n 150/300, 802.11g, etc.)?
802.11n with 450Mbit/s 3x3 Mimo, 5GHz

3d. If you switch to a different wireless type (802.11g or 802.11n if you are using 802.11g) does this change anything?
In 802.11n 2.4GHz throughput is also lower

3e. What channel specifically are you using when this problem is reproducible?
36

3f. In order to understand the wireless environment your AP is working in, please provide the output of the following terminal command:
sudo iw dev wlan0 scan | grep -i "ds parameter set"
sudo iw dev wlp12s0 scan | grep -i "ds parameter set"
        DS Parameter set: channel 36
        DS Parameter set: channel 1
        DS Parameter set: channel 1
        DS Parameter set: channel 1
        DS Parameter set: channel 1
        DS Parameter set: channel 4
        DS Parameter set: channel 6
        DS Parameter set: channel 6
        DS Parameter set: channel 7
        DS Parameter set: channel 9
        DS Parameter set: channel 10
        DS Parameter set: channel 11
        DS Parameter set: channel 11
        DS Parameter set: channel 11
        DS Parameter set: channel 11
        DS Parameter set: channel 12
        DS Parameter set: channel 112

3g. What encryption type are you using (ex. WEP, WPA2-PSK, etc.)?
WPA2-PSK

3h. If you change and remove encryption entirely does this change anything?
Not tested, because only WPA2 makes sense to get high troughput.

3i. Do you have QoS (Quality of Service)/WMM (Wi-Fi Multimedia) enabled?
WMM, Connection properties according to the Fritzbox interface: STBC, TxBF, LDPC, PMF

3j. If you disable/enable QoS/WMM does it change anything?
I dont know how.

3k. What is the current beacon interval (usually default is 100)?
I dont know how.

3l. If you adjust this to 50 does it change anything?
I dont know how.

3m. Does your AP have a firewall enabled?
yes

3n. If you enable/disable the firewall does it change anything?
no

3o. What frequency are you using (2.4GHz, 5GHz, etc.)?
5GHz

3p. If you change frequency does it change anything?
no

Does another wireless device tested with the AP have the same problem as the hardware you initially reported with?
no

What is the distance of the wireless device from the AP?
2.5m

What is the number and type of obstructions between your device and the AP?
direct sight, no obstructions.

6a. If you bring the device close to the AP and eliminate obstructions, does this change anything?
no

Does the issue occur with different APs?
Not tested.

Is it a regression (i.e. did the problem happen in a prior Ubuntu release)? If so, what release specifically did it last work with? If you do not know, could you please test for this in the earliest release of Ubuntu that is supported as per Ubuntu Releases?
Yes it is a regression. (K)ubuntu 12.04.04 LTS worked well.
Linux X-mobile 3.2.0-31-generic #50-Ubuntu SMP Fri Sep 7 16:16:45 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

[ 5.705959] iwlwifi 0000:0c:00.0: loaded firmware version 9.221.4.1 build 25532

X@X-mobile:~$ iperf -c 192.168.10.11 -t 30 -r
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.10.11, TCP port 5001
TCP window size: 23.5 KByte (default)
------------------------------------------------------------
[ 5] local 192.168.10.21 port 59437 connected with 192.168.10.11 port 5001
[ ID] Interval Transfer Bandwidth
[ 5] 0.0-30.0 sec 604 MBytes 169 Mbits/sec
[ 4] local 192.168.10.21 port 5001 connected with 192.168.10.11 port 32793
[ 4] 0.0-30.2 sec 668 MBytes 185 Mbits/sec

Could you please test upstream's compat-wireless backports via https://wiki.ubuntu.com/Kernel/LinuxWireless#Compat-wireless_from_upstream? Please mention in your report the specific version you tested.
Will follow in next comment (after i restarted)

If the above backport did work, does this problem occur in the newest mainline kernel following https://wiki.ubuntu.com/Kernel/MainlineBuilds? Please mention what specific version of the mainline kernel you tested with in your report.
-

If the mainline works, does either the development release or the Ubuntu provided stable compat-wireless backport work following https://wiki.ubuntu.com/Kernel/LinuxWireless#Compat-wireless_in_Ubuntu? Please mention in your report the specific version you tested.
-

Only for Intel wireless chipsets:

14a. Please advise to which firmware version the device is using. Stating the linux-firmware version (ex. apt-cache policy linux-firmware), while necessary, is not the firmware version in use, but the package version of linux-firwmare. In order to find the version in use, one may check dmesg. For example, if the chipset was using the iwlwifi driver:
sudo cat /var/log/syslog | grep "firmware version"
[ 5.720248] iwlwifi 0000:0c:00.0: loaded firmware version 9.221.4.1 build 25532 op_mode iwldvm

14b. Did this work on a prior linux-firmware version? If you don't know, please test a prior release and advise to which version of the firmware, and kernel you tested specifically.
I used the same firmware in Ubuntu 12.04.04.
[ 5.705959] iwlwifi 0000:0c:00.0: loaded firmware version 9.221.4.1 build 25532

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Following questions are answered in later comments.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-24-generic 4.4.0-24.43
ProcVersionSignature: Ubuntu 4.4.0-24.43-generic 4.4.10
Uname: Linux 4.4.0-24-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: mellhen 1530 F.... pulseaudio
CurrentDesktop: KDE
Date: Sun Jun 19 19:32:08 2016
HibernationDevice: RESUME=UUID=f43a948f-c937-45e4-b869-77b1bd2ae610
InstallationDate: Installed on 2016-06-19 (0 days ago)
InstallationMedia: Kubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
MachineType: Dell Inc. Latitude E6400
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-24-generic root=UUID=f93d1069-b1e0-423d-917f-df2e1878d54c ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-24-generic N/A
 linux-backports-modules-4.4.0-24-generic N/A
 linux-firmware 1.157
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/04/2013
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A34
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA34:bd06/04/2013:svnDellInc.:pnLatitudeE6400:pvr:rvnDellInc.:rn:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: Latitude E6400
dmi.sys.vendor: Dell Inc.

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.7-rc1 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.7-rc4-yakkety/

[H.i.M (hir-i-mogul)]

The regression still exists in Kernel 4.7.0-040700rc4-generic.

I tested 3 times:

x@x-E6400:~$ iperf -c 192.168.10.11 -r -t 30
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.10.11, TCP port 5001
TCP window size: 136 KByte (default)
------------------------------------------------------------
[ 5] local 192.168.10.21 port 57022 connected with 192.168.10.11 port 5001
[ ID] Interval Transfer Bandwidth
[ 5] 0.0-30.0 sec 506 MBytes 141 Mbits/sec
[ 4] local 192.168.10.21 port 5001 connected with 192.168.10.11 port 35856
[ 4] 0.0-30.3 sec 192 MBytes 53.2 Mbits/sec
x@x-E6400:~$ iperf -c 192.168.10.11 -r -t 30
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.10.11, TCP port 5001
TCP window size: 170 KByte (default)
------------------------------------------------------------
[ 5] local 192.168.10.21 port 57026 connected with 192.168.10.11 port 5001
[ ID] Interval Transfer Bandwidth
[ 5] 0.0-30.1 sec 500 MBytes 140 Mbits/sec
[ 4] local 192.168.10.21 port 5001 connected with 192.168.10.11 port 35864
[ 4] 0.0-30.5 sec 201 MBytes 55.2 Mbits/sec
x@x-E6400:~$ iperf -c 192.168.10.11 -r -t 30
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.10.11, TCP port 5001
TCP window size: 136 KByte (default)
------------------------------------------------------------
[ 5] local 192.168.10.21 port 57028 connected with 192.168.10.11 port 5001
[ ID] Interval Transfer Bandwidth
[ 5] 0.0-30.0 sec 495 MBytes 138 Mbits/sec
[ 4] local 192.168.10.21 port 5001 connected with 192.168.10.11 port 35871
[ 4] 0.0-30.4 sec 237 MBytes 65.5 Mbits/sec