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#1 2009-01-23 00:50:19

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Registered: 2006-11-26
Posts: 5,819

Slow WLAN with 2.6.28 and Intel 4965 AGN

So here's the deal... I build my own kernel, and skipped 2.6.27 so I went from 2.6.26 to 2.6.28. I am currently running 2.6.28.1. I noticed my WLAN (802.11g) slows down to a crawl when I try to download something, be it HTTP, FTP or torrent. It all locks at roughly 150 KBps. This has been the case for both 2.6.28 and 2.6.28.1

[stijn@hermes ~]$ modinfo iwlcore
filename:       /lib/modules/2.6.28.1-vaio/kernel/drivers/net/wireless/iwlwifi/iwlcore.ko
license:        GPL
author:         Copyright(c) 2003-2008 Intel Corporation
version:        1.3.27k
description:    iwl core
srcversion:     D1F892E114F7784F0FA8918
depends:        mac80211,led-class,cfg80211
vermagic:       2.6.28.1-vaio SMP preempt mod_unload CORE2

The signal is excellent:

root@hermes stijn iwlist intel scan
intel     Scan completed :
          Cell 01 - Address: xx:xx:xx:xx:xx:xx
                    ESSID:"BorrominiNet"
                    Mode:Master
                    Channel:10
                    Frequency:2.457 GHz (Channel 10)
                    Quality=100/100  Signal level:-46 dBm  Noise level=-94 dBm
                    Encryption key:on
                    IE: IEEE 802.11i/WPA2 Version 1
                        Group Cipher : CCMP
                        Pairwise Ciphers (1) : CCMP
                        Authentication Suites (1) : PSK
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s
                              24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s
                              12 Mb/s; 48 Mb/s
                    Extra:tsf=0000003b72b9c223
                    Extra: Last beacon: 13ms ago
[stijn@hermes ~]$ iwlist intel rate
intel     unknown bit-rate information.
          Current Bit Rate=54 Mb/s

Dmesg does not seem to be reporting anything unusual:

[stijn@hermes ~]$ dmesg |grep iwl
iwlagn: Intel(R) Wireless WiFi Link AGN driver for Linux, 1.3.27k
iwlagn: Copyright(c) 2003-2008 Intel Corporation
iwlagn 0000:03:00.0: power state changed by ACPI to D0
iwlagn 0000:03:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
iwlagn 0000:03:00.0: setting latency timer to 64
iwlagn: Detected Intel Wireless WiFi Link 4965AGN REV=0x4
iwlagn: Tunable channels: 11 802.11bg, 13 802.11a channels
iwlagn 0000:03:00.0: PCI INT A disabled
phy0: Selected rate control algorithm 'iwl-agn-rs'
iwlagn 0000:03:00.0: power state changed by ACPI to D0
iwlagn 0000:03:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
iwlagn 0000:03:00.0: restoring config space at offset 0x1 (was 0x100002, writing 0x100006)
iwlagn 0000:03:00.0: firmware: requesting iwlwifi-4965-2.ucode
Registered led device: iwl-phy0:radio
Registered led device: iwl-phy0:assoc
Registered led device: iwl-phy0:RX
Registered led device: iwl-phy0:TX

I haven't tried rolling back to my 2.6.26 build yet; I'd like to know if people out there are experiencing similar issues. The transfer speeds over my LAN (my server is wired to my router) are more or less normal - that is, they have dropped if I scp stuff over from my laptop to the server, but I suspect that's because of the AP that got moved, and the speed is still around 2 MBps, so nowhere near the 150 KBps mark I am experiencing when downloading with my laptop. What makes me think the WLAN is somehow to blame is that a pacman update on my server gives the usual speeds - 1,5 MBps max, that is, so it goes well beyond the 150 KBps mark.

I did find this though:

[stijn@hermes ~]$ grep iwl /var/log/everything.log
Jan 18 00:02:01 hermes iwlagn: Can not allocate SKB buffers
Jan 18 00:02:01 hermes iwlagn: Can not allocate SKB buffers
Jan 18 00:02:02 hermes iwlagn: Can not allocate SKB buffers
Jan 18 00:02:02 hermes iwlagn: Can not allocate SKB buffers
Jan 18 00:02:02 hermes iwlagn: Can not allocate SKB buffers
Jan 18 00:02:02 hermes iwlagn: Can not allocate SKB buffers
Jan 18 00:02:03 hermes iwlagn: Can not allocate SKB buffers
Jan 18 00:02:03 hermes iwlagn: Can not allocate SKB buffers
Jan 18 00:02:05 hermes iwlagn: Can not allocate SKB buffers
Jan 18 00:02:06 hermes iwlagn: Can not allocate SKB buffers

The amount of times this message appears is mindboggling:

[stijn@hermes ~]$ grep iwl /var/log/everything.log|grep allocate|wc -l
988

If it's any help, the message only appears on January 18th, after which it got a reboot to upgrade to 2.6.28.1. A quick glance at Intel's bugtracker and the 2.6.28.1 kernel patch changelog shows that should have been solved. The system is still up and running since the reboot, and no similar messages ever since. The last similar message looks like this:

Jan 18 00:13:05 hermes iwlagn: Can not allocate SKB buffers
Jan 19 02:24:35 hermes iwlagn 0000:03:00.0: PCI INT A disabled

Since the timestamps show more than two hours difference I don't think it is related, but who knows smile.

I also found this bug which seems similar (albeit unrelated), the scp speeds 'upstream' to my server are higher than the scp speed 'downstream' from my server to my laptop.

If anyone has ideas (except for rolling back, which I will try to do soon), shoot smile.


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#2 2009-01-26 01:57:18

wizzard
Member
From: PA, US
Registered: 2006-10-17
Posts: 33

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

I am getting terrible wireless performance out of my 4965 on Arch. It is a fresh install so I can't mess around with different packages to see what's to blame, but I can say that in Windows my 4965 works great.

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#3 2009-01-26 12:09:47

jwcxz
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Registered: 2008-09-23
Posts: 239
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Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

I have a 4965 and have been noticing that the same symptoms are occurring with increased frequency.  In addition, I'm having a problem where the network suddenly disconnects (so far I've been to lazy to look at the logs, but I'll do that next time).


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#4 2009-01-26 12:41:19

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Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

Nice to see some response tongue. I have no network outages, it's just that after some time it seems to fall back to that 150 KBps - sometimes after a few minutes, sometimes after a few hours, sometimes it takes a full day.

I have built 2.6.28.2, I reverted to CFQ as my default scheduler too, since I was playing with deadline and anticipatory before - it would be crazy if that would be the cause of the problem but until you know...

I also compiled my kernel with iwlwifi debugging enabled, reloaded the module

modprobe -rv iwlcore
modprobe -v iwlcore debug=1

and had it run for a while, but it showed no errors. I can't tell whether debugging is enabled in the stock Arch kernel, but I'd guess not. All you have to do is rebuild the kernel from ABS after enabling the debugging option in the config - I could provide my configuration but it is tuned to my hardware, so it's pretty much useless to other people...

What are the max speeds you attain with the AGN card? Also, wizzard, how 'fresh' is your install? Have you had any kernel upgrades or not (from .27 to .28 for example)?


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#5 2009-01-26 15:17:37

litemotiv
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Registered: 2008-08-01
Posts: 5,026

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

I'm getting messages like these:

Jan 26 16:02:14 arch ------------[ cut here ]------------
Jan 26 16:02:14 arch WARNING: at drivers/net/wireless/iwlwifi/iwl-sta.c:708 iwl_set_dynamic_key+0x46a/0x4b0 [iwlcore]()
Jan 26 16:02:14 arch no space for new kewModules linked in: oss_usb oss_hdaudio osscore uvcvideo iwlagn iwlcore mac80211 cdc_wdm cdc_acm vboxdrv nfs lockd nfs_acl sunrpc ipv6 aes_x86_64 aes_generic hci_usb bluet$
Jan 26 16:02:14 arch Pid: 9, comm: events/0 Tainted: P        W  2.6.28-ice #1
Jan 26 16:02:14 arch Call Trace:
Jan 26 16:02:14 arch [<ffffffff8023fbcd>] warn_slowpath+0xcd/0x110
Jan 26 16:02:14 arch [<ffffffffa0190400>] iwl4965_mac_set_key+0x0/0x1c0 [iwlagn]
Jan 26 16:02:14 arch [<ffffffff80497f7d>] __mutex_lock_slowpath+0x21d/0x2b0
Jan 26 16:02:14 arch [<ffffffff80264564>] debug_mutex_add_waiter+0x24/0x80
Jan 26 16:02:14 arch [<ffffffff80497f7d>] __mutex_lock_slowpath+0x21d/0x2b0
Jan 26 16:02:14 arch [<ffffffffa017c7ca>] iwl_set_dynamic_key+0x46a/0x4b0 [iwlcore]
Jan 26 16:02:14 arch [<ffffffffa015d7f2>] __ieee80211_key_todo+0x182/0x280 [mac80211]
Jan 26 16:02:14 arch [<ffffffffa015da60>] key_todo+0x0/0x10 [mac80211]
Jan 26 16:02:14 arch [<ffffffffa015da45>] ieee80211_key_todo+0x15/0x30 [mac80211]
Jan 26 16:02:14 arch [<ffffffff80499955>] _spin_unlock_irq+0x5/0x40
Jan 26 16:02:14 arch [<ffffffff80252e25>] run_workqueue+0x85/0x150
Jan 26 16:02:14 arch [<ffffffff8049957e>] _spin_lock_irqsave+0x3e/0x50
Jan 26 16:02:14 arch [<ffffffff80252f8f>] worker_thread+0x9f/0x110
Jan 26 16:02:14 arch [<ffffffff80257320>] autoremove_wake_function+0x0/0x30
Jan 26 16:02:14 arch [<ffffffff80252ef0>] worker_thread+0x0/0x110
Jan 26 16:02:14 arch [<ffffffff80256f57>] kthread+0x47/0x90
Jan 26 16:02:14 arch [<ffffffff8023ce97>] schedule_tail+0x27/0x70
Jan 26 16:02:14 arch [<ffffffff8020d909>] child_rip+0xa/0x11
Jan 26 16:02:14 arch [<ffffffff80256f10>] kthread+0x0/0x90
Jan 26 16:02:14 arch [<ffffffff8020d8ff>] child_rip+0x0/0x11
Jan 26 16:02:14 arch ---[ end trace fd2d6f8e503050c2 ]---
Jan 26 16:05:01 arch iwlagn: Removing wrong key 1 0x410b
Jan 26 16:05:01 arch ------------[ cut here ]------------

They seem to be 'just' warnings though, and they don't appear with regular intervals, so i'm not sure either..


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#6 2009-01-26 16:17:29

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Registered: 2006-11-26
Posts: 5,819

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

That is with debugging enabled litemotiv?

I just booted into 2.6.28.2, with CFQ as the default scheduler. I'll see how it does.


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#7 2009-01-26 17:57:57

litemotiv
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Registered: 2008-08-01
Posts: 5,026

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

that's without debugging enabled (afaik) and with the deadline scheduler. i'm quite sure the scheduler has nothing to do with it though.


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#8 2009-01-27 17:52:09

zenlord
Member
From: Belgium
Registered: 2006-05-24
Posts: 1,218
Website

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

I'm having network trouble since the upgrade to .28. I'm using the ath9k-driver though.

Using ndiswrapper is a temporary workaround, but gives me a reliable connection. Using the ath9k-driver I can connect, but surfing or downloading is out of the question: time outs, lost connections etc.

Might be a bigger problem than only 4965...

Zl.

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#9 2009-01-28 04:56:53

sud_crow
Member
From: Argentina
Registered: 2003-06-30
Posts: 546
Website

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

jwcxz wrote:

I have a 4965 and have been noticing that the same symptoms are occurring with increased frequency.  In addition, I'm having a problem where the network suddenly disconnects (so far I've been to lazy to look at the logs, but I'll do that next time).

I'm having this issues as well.
I cant seem to find an option to make it work without getting a disconnection after 25/30 minutes.


I have tried to trace it down to something, and all I see every time it happens is this:

wlan0: no IPv6 routers present
iwlagn: Microcode SW error detected.  Restarting 0x82000000.
iwlagn: Can't stop Rx DMA.
iwlagn: No space for Tx
iwlagn: Error sending SENSITIVITY_CMD: enqueue_hcmd failed: -28
iwlagn: SENSITIVITY_CMD failed

Although from time to time, I also see this (via dmesg, after I realize I'm disconnected):

mac80211-phy0: failed to remove key (0, 00:1d:7e:dc:a9:94) from hardware (-22)                                                              
iwlagn 0000:0b:00.0: PCI INT A disabled                                                                                                     
wlan0: deauthenticating by local choice (reason=3)

I dont know whats going on, but Arch is having *lots* of problems with this Intel iwl4965 wireless card lately (I couldnt get the interface recognized at boot time for a couple of kernel releases not long ago). I'm this close to try another distribution to see if the problem is with the latest kernel series or what, althouth it seems Arch its not the only one with issues <https://bugs.launchpad.net/linux/+bug/200509>.

Last edited by sud_crow (2009-01-28 05:01:26)


Leonardo Andrés Gallego
www.archlinux-es.org || Comunidad Hispana de Arch Linux

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#10 2009-01-28 08:02:51

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Registered: 2006-11-26
Posts: 5,819

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

Well all I can say is, with cfq, my network performance is back on track. System is sluggish as hell though...  Wish they never invented this darn cfq thing!

I'll see what anticipatory does, but deadline seems out of the window, at least for my desktop.


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#11 2009-02-21 10:19:04

Raedwulf
Member
Registered: 2008-04-26
Posts: 24

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

I'm getting similar issues - LAN speeds are about 1.5-2 Mb/s while internet speeds are about 100-300 Kb/s (kilo bytes/s) when its mean to be a 20Mbit connection (maxes at 2Mb/s).
Strangely at university i get better wireless speeds (about 400kb/s) than at home

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#12 2009-07-10 17:29:56

Lazer
Banned
Registered: 2007-08-02
Posts: 111

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

This card is crap!
I have it on my laptop snce January and sometimes it works as it should, with download speeds reaching the maximun for my internet connection (500 KB/s). However, most of the times web surfing is slow as well as transfers, with a max speed of 75 KB/s. I use the 2.6.28 kernel. Did anyone find a real solution? it's driving me crazy! Why does it work properly from time to time? It's more like a random thing...

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#13 2009-07-10 18:29:32

litemotiv
Forum Fellow
Registered: 2008-08-01
Posts: 5,026

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

Lazer wrote:

This card is crap!
I have it on my laptop snce January and sometimes it works as it should, with download speeds reaching the maximun for my internet connection (500 KB/s). However, most of the times web surfing is slow as well as transfers, with a max speed of 75 KB/s. I use the 2.6.28 kernel. Did anyone find a real solution? it's driving me crazy! Why does it work properly from time to time? It's more like a random thing...

you should at least upgrade to the latest kernel and microcode, the intel driver development goes pretty fast


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#14 2009-07-17 11:27:26

buddabrod
Member
From: Germany
Registered: 2007-02-25
Posts: 220

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

I have this card for 2 years now and I'm happy that I can at least join our university's wireless network (that didnt work for quite some time because of a faulty driver) which works with WPA-EAP.

The problem of ongoing firmware errors and stopping traffic has never been solved and I tend to stop believing in any fix. I think I'll buy some atheros card or something like that.

Last edited by buddabrod (2009-07-17 11:28:01)

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#15 2012-01-29 18:04:49

skeptikos
Member
Registered: 2009-03-07
Posts: 11

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

Hey, I'm having this issue too. I've never had problems with this card until I did a fresh install today. It seems like this isn't an arch issue though. When someone finds a solution, please take the time to post here.

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#16 2012-01-29 18:33:55

skeptikos
Member
Registered: 2009-03-07
Posts: 11

Re: Slow WLAN with 2.6.28 and Intel 4965 AGN

Okay, There is at least a short term solution here: http://ubuntuforums.org/showthread.php?t=1859558&page=3

I can verify that this works and that the entry in modprobe.d/options.conf also worked.

Last edited by skeptikos (2012-01-30 11:49:44)

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