Public bug reported: Binary package hint: linux-image-2.6.38-8-generic
I have a Lenovo Thinkpad T61p with the following wifi NIC: 03:00.0 Network controller: Intel Corporation PRO/Wireless 4965 AG or AGN [Kedron] Network Connection (rev 61) When using wireless networks with WPA, the performance is extremely poor and sometimes the computer crashes (kernel panic) when transfering large amounts of data via wireless. Here are some test results from iperf: ------------------------------------------------------------ Client connecting to 10.0.1.101, TCP port 5001 TCP window size: 0.02 MByte (default) ------------------------------------------------------------ [ 6] local 10.0.1.50 port 55264 connected with 10.0.1.101 port 5001 [ 3] local 10.0.1.50 port 55261 connected with 10.0.1.101 port 5001 [ 4] local 10.0.1.50 port 55262 connected with 10.0.1.101 port 5001 [ 5] local 10.0.1.50 port 55263 connected with 10.0.1.101 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-61.4 sec 7.30 MBytes 0.12 MBytes/sec [ 5] 0.0-62.9 sec 6.33 MBytes 0.10 MBytes/sec [ 6] 0.0-62.9 sec 5.34 MBytes 0.08 MBytes/sec [ 4] 0.0-65.3 sec 12.9 MBytes 0.20 MBytes/sec [SUM] 0.0-65.3 sec 31.9 MBytes 0.49 MBytes/sec Compared to wired network: ------------------------------------------------------------ Client connecting to pc7, TCP port 5001 TCP window size: 0.02 MByte (default) ------------------------------------------------------------ [ 4] local 10.0.0.50 port 42857 connected with 10.0.0.7 port 5001 [ 5] local 10.0.0.50 port 42858 connected with 10.0.0.7 port 5001 [ 3] local 10.0.0.50 port 42856 connected with 10.0.0.7 port 5001 [ 6] local 10.0.0.50 port 42859 connected with 10.0.0.7 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-60.0 sec 1685 MBytes 28.1 MBytes/sec [ 4] 0.0-60.0 sec 1687 MBytes 28.1 MBytes/sec [ 5] 0.0-60.0 sec 1676 MBytes 27.9 MBytes/sec [ 6] 0.0-60.0 sec 1667 MBytes 27.8 MBytes/sec [SUM] 0.0-60.0 sec 6715 MBytes 112 MBytes/sec (above data in pastebin: http://paste.adora.dk/P2060.txt) Note, I have also tried using a single thread: Client connecting to malbec, TCP port 5001 TCP window size: 0.02 MByte (default) ------------------------------------------------------------ [ 3] local 10.0.0.254 port 44754 connected with 10.0.0.1 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-60.3 sec 34.0 MBytes 0.56 MBytes/sec (pastebin: http://paste.adora.dk/P2064.txt) This is 802.11g network and the computer is right next to access point. So performance should be somewhere near 54mbit/s. I have tried using different channels as well as tried different access points and verified the bug on at least two laptops using Kubuntu 11.04 and the same wifi NIC. Futhermore, when using the wifi bandwidth (e.g. by downloading a file with wget or measuring with iperf), the network latency grows huge. Pinging the gateway or other nodes on the LAN gives ping times of several seconds. I have noticed this bug: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/299468 It seems similar, but it is very old and marked expired. This could be a regression that has re-introduced this bug, or it can be a completely new bug. I am not sure. However, I really think this should be addressed, as it makes wifi almost completely unusable. Please let me know what I can do to help fix or debug this bug further. Some system/hardware info: Linux malbec 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:24 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux lspci http://paste.adora.dk/P2068.txt lsusb http://paste.adora.dk/P2069.txt cat /proc/cpuinfo http://paste.adora.dk/P2071.txt lsmod http://paste.adora.dk/P2072.txt ** Affects: linux (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/788053 Title: Poor performance and crashes with Intel Wireless driver (iwlagn) -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
