network connection problem seems to be causing long delays

[Rhubbarb]

Background: I'm a recovering ex-Windoze user; earlier this year, I migrated to Kubuntu Linux.

I have a PC Specialist Cosmos II 17.3" laptop. This is my first home Linux machine. I installed Kubuntu 13.10 and upgraded to 14.04. I've had a few miscellaneous problems (e.g. with DVD playback), but have managed to iron most of them out now. Going back to Windoze is horrible; My Kubuntu machine boots and shuts down very quickly; It does its updates when it's convenient for me. On the whole the machine, though the hardware is fairly basic, is very fast. For the most part, my experience with Kubuntu has been very good and very smooth.

Occasionally, I have noticed that the machine appears to hang. Terminals and GUI applications seem to be fine, but the desktop panel becomes very unresponsive (taking, say 15 seconds to respond to a mouse click). Restarting the desktop (via `killall plasma-desktop && plasma-desktop`) does not help.

More recently, I have found that this behaviour occurs when my broadband connection is poor or unavailable. That is, I have a WiFi connection to my router, but the router has lost its connection to the Internet. (My broadband is a bit flaky sometimes.)

Now, I can workaround the problem by disabling the WiFi connection; this is the main reason I suspect that this is network-related. I have had these symptoms when connected to my own WiFi at home, and also when at other locations, so I don't think it's directly related to external hardware.

As I usually run the Network Monitor widget, I have tried removing that, but that makes no difference, so I don't believe that's the culprit.

I don't think there's anything else particularly unusual about how I have KDE configured. I'm afraid I don't know what network drivers I have; I'd guess that these are the distribution's defaults.

I wonder whether Kubuntu is trying to poll an external server for update news, or something like that.

Any clues would be much appreciated.
Thanks.

[GreyGeek]

.... More recently, I have found that this behaviour occurs when my broadband connection is poor or unavailable. That is, I have a WiFi connection to my router, but the router has lost its connection to the Internet. (My broadband is a bit flaky sometimes.)

Now, I can workaround the problem by disabling the WiFi connection; this is the main reason I suspect that this is network-related. I have had these symptoms when connected to my own WiFi at home, and also when at other locations, so I don't think it's directly related to external hardware. ....

Sounds like the wifi chip on your PC is not able to maintain a stable connection. I had a similar problem last year, which I resolved by upgrading to a more recent kernel.

What happens when you use an ethernet cable connection to your wireless router?

Meanwhile, collect some data. In a Konsole enter
lspci | grep Network
and report what the make and model of your wifi chip is. Mine gives:

lspci | grep Network
0d:00.0 Network controller: Qualcomm Atheros AR9462 Wireless Network Adapter (rev 01)

Mine shows that my laptop has an Atheros Ar9462 wireless chip. What does yours show?

[Rhubbarb]

…
Mine shows that my laptop has an Atheros Ar9462 wireless chip. What does yours show?

Thanks @Teunis and @GreyGeek for the replies.

Sorry for the delay acknowledging.

@Teunis: I am equally confused by the apparent connection between the panel (or desktop) and the network. When the problem occurs, the panel freezes, so I can't see either CPU or network load. I'm guessing that the CPU (2 physical cores) is not at maximum, as apps still seem responsive. I'll take a look at `top` and whatever command line I can find for network load (or perhaps an alternative GUI/widget). As for what the panel/desktop have that require network: the network monitor; I also gave gmail-plasmoid; other than that there's only the muon update notifier.

To answer to one of @GreyGeek's questions:

$ lspci | grep Network
04:00.0 Network controller: Intel Corporation Wireless 7260 (rev 73)

You also asked me to compare the behaviour with a wired connection. That's a good idea; I'll try that soon, and get back. (I'll need to find a way to emulate poor Broadband; it might be as simple as pulling out the WAN cable.)

Thanks again.

[GreyGeek]

I googled your wifi chip and noticed that there are a LOT of misery stories about it out there. And, there are some cures. Here is one:

try the newer firmware file. First, back up the existing file: cd /lib/firmware
sudo mv iwlwifi-7260-7.ucode iwlwifi-7260-7.ucode.bak
Now download the newer file:
sudo wget https://git.kernel.org/cgit/linux/ke...i-7260-7.ucode
Reboot

Here was the solution that worked for me:

you need to update the kernel to 3.11

but Kubuntu 14.04 uses "3.13.0-29-generic #53-Ubuntu SMP Wed Jun 4 21:00:20 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux"

Another solution:

My card is Intel Corporation Wireless 7260 (rev 73) and I have to connect RJ45 first than add driver (under System Settings -> Additional Drivers and activate several of them after that I got WiFi.

It seems your chip is not a friendly one.

[Rhubbarb]

[SOLVED]

[Sorry for the huge delay between posting my question and this solution. I had put up with the symptoms for far too long. After making my change, I wanted to run like this for a reasonable period as a fair test.]

My problem turned out to be caused by `gmail-plasmoid` (which I alluded to previously) running in my system tray. I removed that from the system tray and have had none of the delays since.

There are various alternative utilities available. I tried a few, but the one I've settled on is `kgmailnotifier` (mainly as it supports domain gmail addresses). This alternative program has not caused any of the delays. In addition `kgmailnotifier` has been more stable; `gmail-plasmoid` had lost its settings or stopped functioning after some updates.

Thanks again for all the replies.

[GreyGeek]

Nice sleuthing!

A good utility to check on established network connections is netstat:
netstat -lap
You can man netstat to find out more about it.