14e4:4331 Slow transfer speeds with BCM 4331

[Jussi Pakkanen]

The BCM 4331 wireless chip has slow transfer speeds compared to OSX.

I tested by transferring a big file over the wireless between this machine and a server that is connected to the wireless router by a wired connection using scp. The transfer speeds are:

OSX upload: 7 MB/s
OSX download: 8.5 MB/s
Linux upload: 800 kB/s
Linux download: 1.9 MB/s

Uploading on Linux is 10 times slower than uploading on OSX. CPU load is ~14% when downloading in Linux.

The distance between the AP and the laptop was ~5 meters with direct line of sight between the two. The security used is WPA2.

The only similar symptom I found by web searching is this: http://ubuntuforums.org/showthread.php?t=1964768&page=2

The workaround given on that page do not work for me.

This is not a regression. The driver for this chipset was added in Precise and that had the same problem.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: linux-image-3.5.0-17-generic 3.5.0-17.28
ProcVersionSignature: Ubuntu 3.5.0-17.28-generic 3.5.5
Uname: Linux 3.5.0-17-generic x86_64
ApportVersion: 2.6.1-0ubuntu4
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: jpakkane 2017 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory: 'iw'
Date: Mon Oct 22 14:45:46 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64+mac (20120220)
MachineType: Apple Inc. MacBookPro8,1
MarkForUpload: True
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.5.0-17-generic root=UUID=725f2433-59c8-46cc-9c13-ad2e4ad1548d ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.5.0-17-generic N/A
 linux-backports-modules-3.5.0-17-generic N/A
 linux-firmware 1.95
SourcePackage: linux
UpgradeStatus: Upgraded to quantal on 2012-08-06 (77 days ago)
dmi.bios.date: 01/24/12
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBP81.88Z.0047.B27.1201241646
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-94245B3640C91C81
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookPro8,1
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-94245B3640C91C81
dmi.modalias: dmi:bvnAppleInc.:bvrMBP81.88Z.0047.B27.1201241646:bd01/24/12:svnAppleInc.:pnMacBookPro8,1:pvr1.0:rvnAppleInc.:rnMac-94245B3640C91C81:rvrMacBookPro8,1:cvnAppleInc.:ct10:cvrMac-94245B3640C91C81:
dmi.product.name: MacBookPro8,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.

[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 v3.7 kernel[0] (Not a kernel in the daily directory) and install both the linux-image and linux-image-extra .deb packages.

Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. Please only remove that one tag and leave the other tags. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text.

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'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-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/v3.7-rc2-raring/

[penalvch (penalvch)]

Jussi Pakkanen, thank you for testing the mainline kernel. Could you please provide the information following https://wiki.ubuntu.com/Kernel/LinuxWireless#Bug_Report_Minimum_Requirement_Information ?

[Jussi Pakkanen (jpakkane)]

I can't check the original AP currently because I will be in Copenhagen for two weeks. Running speedtest.net in the local network gives transfer speeds of 6.67 MB down / 3.93 MB up.

[Jussi Pakkanen (jpakkane)]

Running speedtest.net at home gives me 10MB / 1MB, which is the speed of my Internet connection. Transfers within the network are still slow, though.

I made a test application in Python that transfers big files over a socket connection. It reads the data like this:

block = self.socket.recv(1024*1024*10)

and then prints the received block size. With a wired connection I get relatively large numbers but when using wireless I get the value 1448 over 99% of the time and some other values such as 4344 and 2896 every now and again. If I add a sleep after every block the number gets bigger but transfer speed remains the same.

When running the transfer test, top shows that a process called irq/17-b43 is taking over 10% CPU time.

[Seth Forshee (sforshee)]

One important note about support for BCM4331 (specifically for the PHY it uses) is that it is reverse-engineered and very much suboptimal and incomplete. 802.11n support is completely missing.

I did some tests on a Macbook Pro 8,2 with iperf and got similar numbers for TCP download. My upload speeds were comparable to the download speeds, which doesn't match your results. I don't really know what can be done to fix it though; we really just don't know how to properly configure the hardware. Broadcom indicated at one point that they have plans to support BCM4331 in brcmsmac, but there's been no indication of when this might happen.

[penalvch (penalvch)]

Jussi Pakkanen / Seth Forshee, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, please just make a comment to this.

As well, as a potential WORKAROUND, would the Broadcom drivers provided via https://launchpad.net/ubuntu/+source/bcmwl provide improved performance?

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Jose C. Massón (jose-masson)]

I have the same issue:

~ ❯❯❯ lspci -nn -d 14e4:
02:00.0 Ethernet controller [0200]: Broadcom Corporation NetXtreme BCM57765 Gigabit Ethernet PCIe [14e4:16b4] (rev 10)
02:00.1 SD Host controller [0805]: Broadcom Corporation BCM57765/57785 SDXC/MMC Card Reader [14e4:16bc] (rev 10)
03:00.0 Network controller [0280]: Broadcom Corporation BCM4331 802.11a/b/g/n [14e4:4331] (rev 02)

~ ❯❯❯ sudo dmidecode -s system-product-name
MacBookPro8,1

~ ❯❯❯ uname -a
Linux manolito 3.13.0-45-generic #74-Ubuntu SMP Tue Jan 13 19:36:28 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

~ ❯❯❯ lspci -nnv
03:00.0 Network controller [0280]: Broadcom Corporation BCM4331 802.11a/b/g/n [14e4:4331] (rev 02)
 Subsystem: Apple Inc. AirPort Extreme [106b:00d6]
 Flags: bus master, fast devsel, latency 0, IRQ 17
 Memory at a0600000 (64-bit, non-prefetchable) [size=16K]
 Capabilities: <access denied>
 Kernel driver in use: bcma-pci-bridge