major throughput difference (between upload and download) when using iwl3945

[Matthew Fisher]

Binary package hint: linux-ubuntu-modules-2.6.22-14-generic

Per this bug report ( https://bugs.launchpad.net/ubuntu/+source/linux-ubuntu-modules-2.6.22/+bug/158045 )
and all the problems surrounding ipw3945--including my own connection dropping under x86 and inoperability
under amd64--I started using the iwl3945 module as a replacement.

When transferring files (I've used rsync and scp), I noticed a huge difference in the throughput between
uploading and downloading. I only jotted down the rates of a single 250MB file via scp (and I know there
is overhead involved) with an UL rate of around 1 MB/s and a DL rate of 103 KB/s.
Rsync is faster, of course, but the transfer ratio is about the same.

"uname -a" reports:
Linux system76 2.6.22-14-generic #1 SMP Sun Oct 14 23:05:12 GMT 2007 i686 GNU/Linux

The relevant portion about the network chipset from "lspci -v" is:
Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)
Subsystem: Intel Corporation Unknown device 1000
Flags: bus master, fast devsel, latency 0, IRQ 17
Memory at f8000000 (32-bit, non-prefetchable) [size=4K]
Capabilities: [c8] Power Management version 2
Capabilities: [d0] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable-
Capabilities: [e0] Express Legacy Endpoint IRQ 0

This occurs when running x86 Gutsy on the current revision of the System76 Serval Performance.
Please let me know if/what additional information you need.

[Vincenzo Ciancia (vincenzo-ml)]

this also occurs to me on hardy, the network connection is about 10x slower. It has peaks at maximum rate, but connection immediately slows down, and often connections time out.

[Vincenzo Ciancia (vincenzo-ml)]

$ dmesg |grep -i iwl
[ 25.228225] iwl3945: Intel(R) PRO/Wireless 3945ABG/BG Network Connection driver for Linux, 1.1.17kds
[ 25.228230] iwl3945: Copyright(c) 2003-2007 Intel Corporation
[ 25.228368] iwl3945: Detected Intel PRO/Wireless 3945ABG Network Connection
[ 27.929081] iwl3945: Tunable channels: 13 802.11bg, 23 802.11a channels
[ 27.930261] phy0: Selected rate control algorithm 'iwl-3945-rs'

$ lspci
02:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)

$lspci -v
02:00.0 0280: 8086:4222 (rev 02)

[Erik Vetters (evetters)]

Hi,

this also happens on a Dell D420 here. I can't get more than 40-50 KB/s DL, before it was around 500 KB/s at this AP. UL is around 90-100KB/s like before ...

I have DSL connection 16Mbit/1Mbit

up2date Hardy from 08-Feb 2008

uname -a
======

Linux siXel 2.6.24-5-generic #1 SMP Thu Jan 24 19:45:21 UTC 2008 i686 GNU/Linux

iwconfig eth1
=========

eth1 IEEE 802.11g ESSID:"....."
          Mode:Managed Frequency:2.437 GHz Access Point: 00:0F:B5:59:23:C6
          Bit Rate=11 Mb/s Tx-Power=27 dBm
          Retry min limit:7 RTS thr:off Fragment thr=2346 B
          Link Quality=77/100 Signal level=-57 dBm Noise level=-127 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:0 Missed beacon:0

ifconfig
=====

eth1 Link encap:Ethernet Hardware Adresse 00:13:02:d3:a0:11
          inet Adresse:192.168.1.54 Bcast:192.168.1.255 Maske:255.255.255.0
          inet6-Adresse: fe80::213:2ff:fed3:a011/64 Gültigkeitsbereich:Verbindung
          UP BROADCAST RUNNING MULTICAST MTU:1492 Metrik:1
          RX packets:3989 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4454 errors:0 dropped:0 overruns:0 carrier:0
          Kollisionen:0 Sendewarteschlangenlänge:1000
          RX bytes:4115103 (3.9 MB) TX bytes:603489 (589.3 KB)

lshw -C network
==========

  *-network
       description: Wireless interface
       product: PRO/Wireless 3945ABG Network Connection
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:0c:00.0
       logical name: wmaster0
       version: 02
       serial: 00:13:02:d3:a0:11
       width: 32 bits
       clock: 33MHz
       capabilities: bus_master cap_list logical ethernet physical wireless
       configuration: broadcast=yes driver=iwl3945 ip=192.168.1.54 latency=0 module=iwl3945 multicast=yes wireless=IEEE 802.11g

lspci
====
0c:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)

dmesg
====

[ 26.975052] iwl3945: Intel(R) PRO/Wireless 3945ABG/BG Network Connection driver for Linux, 1.1.17kds
[ 26.975060] iwl3945: Copyright(c) 2003-2007 Intel Corporation
[ 26.975268] iwl3945: Detected Intel PRO/Wireless 3945ABG Network Connection
[ 28.835595] iwl3945: Tunable channels: 13 802.11bg, 23 802.11a channels
[ 28.837336] phy0: Selected rate control algorithm 'iwl-3945-rs'

Many Greetings
Erik

[Erik Vetters (evetters)]

Hi,

this bug is already reported upstream

http://bughost.org/bugzilla/show_bug.cgi?id=1592

I also saw similiar reports on some forums for fedora 8 and SuSE

Greetings
Erik

[Mikael Gerdin (mgerdin)]

I am also experiencing this bug with iwl3945 on my amd64 hardy system.

I've just tried to recompile the ubuntu kernel sources with the in-kernel iwlwifi enabled and that works a whole lot better. With the version in l-u-m i get about 100KB/s download speed with my computer about half a meter from my AP, and 500ms+ latency when downloading something.
With the in-kernel version i get 1300KB/s and 100ms latency at that speed.
The only things i changed in the kernel config was to enable the iwlwifi and the in-kernel alsa driver for my soundcard (for convenience).

I think that if this bug is not fixed soon, maybe Hardy should be released with the in-kernel version of iwl, at least for the 3945, because right now it's pretty unusable.
I use WPA2 on my wlan, but I've seen the same problem on unencrypted networks.

[Mikael Gerdin (mgerdin)]

Now I've tried the second approach, I've updated the iwl-drivers in the l-u-m package to 1.2.25 and 1.0.4 for mac80211 and rebuilt it. This is even better, wpa authentication is done in half the time it was before, and throughput performance is really good.
Instructions on how to do this is in bug #183928

[Pat Regan (thehead)]

I also updated the iwl drivers in the gutsy linux-ubuntu-modules to 1.2.25 and 1.0.4. There is definitely a huge improvement, but it isn't perfect. When things are working properly my speed on long file copies fluctuates between 1300 and 2300 KB per second. When things go 'bad' I'm luck to break 100 KB per second. The speeds are the same with the ipw3945 modules, or the stock or upgraded iwl3945 modules.

However, the when things are slow with the ipw3945 module I see lots of errors under ifconfig and iwconfig. iwl3945 shows me nothing, it just gets slow and if the pipe is full (at 100 KB/sec) the latency goes to 400+ on pings on my local subnet.

The 1.2.25/1.0.4 combo only gets slow, and stays slow, if I walk my laptop to a part of the house where my signal isn't so great. Once it gets slow, it won't speed up without a disconnect/reconnect. The stock Gutsy iwl3945 and ipw3945 will randomly, and quite regularly, get slow while I'm right within a few feet of my access point. I've only been running 1.2.25/1.0.4 for about a day so far, but it hasn't slowed down 'on its own' yet.

My cheater fix to speed up the stock iwl3945 when it got stuck in the mud was to 'rfkill; sleep 5;un-rfkill' from the command line. That would normally speed things up for a few minutes, killing it for less than 5 seconds didn't usually fix things.

What is would be the process to get the updated iwl drivers in place for Hardy?

[Erik Vetters (evetters)]

hi,

For me this is complete gnone since the upgrade to iwl 1.2.0

It is gnone since the upgrade to linux-ubuntu-modules-2.6.24-14 ...

[ 43.069452] iwl3945: Intel(R) PRO/Wireless 3945ABG/BG Network Connection driver for Linux, 1.2.0
[ 43.069459] iwl3945: Copyright(c) 2003-2007 Intel Corporation
[ 43.149777] iwl3945: Detected Intel PRO/Wireless 3945ABG Network Connection
[ 43.755813] iwl3945: Tunable channels: 13 802.11bg, 23 802.11a channels
[ 43.759547] wmaster0: Selected rate control algorithm 'iwl-3945-rs'

I now have fully download and upload rate as it should be ...

Greetings and THX
Erik

[Vincenzo Ciancia (vincenzo-ml)]

It seems to me that the slowdown depends on the used router. How could one debug and see if there are timeouts of some sort? I am now using latest driver from linux-backport-modules, and at home transfers are terrific slow even in the local network.

[Markus Golser (golserma)]

I fixed this by setting my router to g-only mode.

I have a Linksys WRT54GL running openwrt kamikaze (broadcom chipset)

[Vincenzo Ciancia (vincenzo-ml)]

My router only has -b mode, this may be the problem and may explain why not everybody is getting it. In any case the driver used in gutsy had no such problems so it must be a problem of drivers, not the router.

[Vincenzo Ciancia (vincenzo-ml)]

I found a solution and I am really happy of this :) I downloaded the latest drivers from

http://linuxwireless.org/en/users/Download

and transfer rate is very good. Please test. I think the version of the driver is in this string from dmesg:

[ 34.094703] iwl3945: Intel(R) PRO/Wireless 3945ABG/BG Network Connection driver for Linux, 1.2.26k

so it seems we need version 1.2.26. Also, googling around, this seems a problem of 802.11b mode.

[Vincenzo Ciancia (vincenzo-ml)]

To install the drivers, remove linux-backport-modules-KERNEL_VERSION-generic and check that /lib/modules/KERNEL_VERSION/updates does not exist, so that you'll be sure to use the new drivers.

[Vincenzo Ciancia (vincenzo-ml)]

I spoke too early. It worked for an hour but it was by chance. I still have this problem.

[markb (mark-blakeney)]

I have this problem on my Dell 640m Inspiron laptop. My downloads are about 2MB/s after a clean reboot but drop to about 700KB/s after a few minutes and never recover, until the next reboot.

I've tried the current linux-ubuntu-modules-2.6.24-19-generic (with iwl3945 v1.2.0), linux-backports-modules-2.6.24-19-generic (with iwl3945 v1.2.25), and compat-wireless-2008-07-25 (with iwl v1.2.26k) and all exhibit the problem and with no difference between them.

I also configured my router as 802.11g only (as suggested above) but that made no difference.

This wireless chipset is so common and this bug is such a PITA that I'm surprised there are not more people clamoring here for a fix?

[Vincenzo Ciancia (vincenzo-ml)]

I don't know anymore where I found this information on the web, but it seems to me that in intrepid, if I use qos_enable=0 as a module argument for iwl3945, everything works just fine. Will keep on testing and eventually report any further problem.

Kernel version: 2.6.27-4-generic

[markb (mark-blakeney)]

This problem disappeared for me by changing my wireless access point from a Billion to a Linksys WRT54GL (running Tomato 1.21 firmware). Still believe it is a bug in the iwl3945 driver but a bug not exposed for me anymore.

[Vincenzo Ciancia (vincenzo-ml)]

Forget my last comment, it is not true - the problem is still there.

[Leann Ogasawara (leannogasawara)]

I this still an issue with the final Intrepid Ibex 8.10 release? If the issue remains, care to try installing the linux-backports-modules-intrepid package as it contains and updated compat-wireless stack. For now I'm going to move this bug forward to target the actively developed linux kernel package. The reason is that during the Intrepid development cycle the linux-ubuntu-modules package was merged with the linux kernel package. Thanks.

[ubuntu_demon (ubuntu-demon)]

This bug is still here. I'm getting 14 mbit down versus 2 mbit up (I've tested this using netperf -I 99,5 -i 50 -H some-ip-which-is-running-netserver).

[Leann Ogasawara (leannogasawara)]

Was that with or without linux-backports-modules-intrepid installed?

[Vincenzo Ciancia (vincenzo-ml)]

Under intrepid I was using the kernel version 2.6.27-11 and speed was capped at around 40kbyte/s (empiric measurement over an ftp on my fixed pc attached by cable on the same router). Now I installed linux-backports-modules-intrepid and speed is around 20kbyte/s - the router is an 802.11b.

[Maxime Chéramy (maxime81)]

Same problem here. I've tried with and without linux-backports-modules-intrepid.
An example of a what I can't do :
My ISP provides me a box and with it I can watch TV on my laptop. But it works during few minutes but then the image freeze, a ping to the router go from 1ms to 8000ms !

[Jeremy Foshee (jeremyfoshee)]

This bug report was marked as Triaged a while ago but has not had any updated comments for quite some time. Please let us know if this issue remains in the current Ubuntu release, http://www.ubuntu.com/getubuntu/download . If the issue remains, click on the current status under the Status column and change the status back to "New". Thanks.

[This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

[Brad Figg (brad-figg)]

This bug was filed against a series that is no longer supported and so is being marked as Won't Fix. If this issue still exists in a supported series, please file a new bug.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.