Arch Linux

SgPepper

Member

Registered: 2014-05-16

Posts: 20

Fast downloads kill my connection

Dear arch community,

I am running into a problem with my wireless network connection. Basically, when I start a "big" download, either direct download, torrent, or on steam, my connection "drops". This does not happen with arch repository downloads (probably because of the low download speed), and also throttling steam downloading speed (to 64 kbps) seems to prevent the problem. By "drop", I mean that I no longer can access the internet using the connection (ping doesn't work, neither using ip or url address), but my computer is still connected to the router. And then, it sufficies to unload/reload the wireless kernel module for the computer to reconnect and be able to access the internet again.

Here is a sample ping command running while I start a steam download :

ping google.com

PING google.com (74.125.206.102) 56(84) bytes of data.
64 bytes from wk-in-f102.1e100.net (74.125.206.102): icmp_seq=1 ttl=44 time=39.4 ms  
  [runs fine for a while]
64 bytes from wk-in-f102.1e100.net (74.125.206.102): icmp_seq=6 ttl=44 time=39.8 ms
64 bytes from wk-in-f102.1e100.net (74.125.206.102): icmp_seq=7 ttl=44 time=42.0 ms
  [at this point I start a download]
64 bytes from wk-in-f102.1e100.net (74.125.206.102): icmp_seq=8 ttl=44 time=44.4 ms
64 bytes from wk-in-f102.1e100.net (74.125.206.102): icmp_seq=9 ttl=44 time=69.8 ms
64 bytes from wk-in-f102.1e100.net (74.125.206.102): icmp_seq=10 ttl=44 time=179 ms
64 bytes from wk-in-f102.1e100.net (74.125.206.102): icmp_seq=11 ttl=44 time=149 ms
  [high pings for a while here(12 lines cut), but sometimes only 1 packet makes it through]
64 bytes from wk-in-f102.1e100.net (74.125.206.102): icmp_seq=23 ttl=44 time=181 ms
64 bytes from wk-in-f102.1e100.net (74.125.206.102): icmp_seq=24 ttl=44 time=189 ms
  [freezes here for 20-30 seconds]
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
  [loops this message until I reset the interface be reloading the kernel module]
  [I interrupt the command]

$ ping google.com
ping: google.com: Name or service not known

I'm using a netgear wnda3100v2 usb wifi adapter, with the windows drivers and ndiswrapper. I can post the driver files if you think it's useful. Some outputs that may be useful :

lsusb

Bus 008 Device 003: ID 0846:9011 NetGear, Inc. WNDA3100v2 802.11abgn [Broadcom BCM4323]
Bus 008 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 002: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 007 Device 003: ID 05e3:0716 Genesys Logic, Inc. USB 2.0 Multislot Card Reader/Writer
Bus 007 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 002: ID 1131:1004 Integrated System Solution Corp. Bluetooth Device
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

ndiswrapper -l

bcmn43xx64 : driver installed
	device (0846:9011) present

So far, I've tried using "echo 83886080 > /proc/sys/net/core/wmem_max" (the original value being 212992), but it does not solve the problem (it might delay it a bit, but I'm not even sure). I've seen other commands like this one, and I'm looking into, but they seem more suitable for servers, and honestly, I'd rather not mess with these settings if I dont know what it does.

So if you have any suggestions, that would be awesome. I'll stay around for a while if you need some more info here. Thanks !

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,768

Re: Fast downloads kill my connection

That is a new one on me.  Unfortunately, you are a bit of a test pilot here with a USB NIC and wrapped opaque Windows drivers, what could possibly go wrong? 

I did a Google search on ping: sendmsg: No buffer space available and hit a couple Ubuntu and Stackexchange posts.  Following some links in the Ubuntu post (my first hit) I came across this:

http://www.cyberciti.biz/faq/linux-tcp-tuning/

But, be aware, Arch does not use a /etc/sysctl.conf file, we use a /etc/sysctl.d directory into which individual configuration files go.  Be sure to read man sysctl for details on how to change kernel parameter at boot.
It might be (stated without proof) that changing /proc/sys/net/core/wmem_max directly in a running kernel will not work.  Did you try reading it back after you did that?

Anyway, be advised that I have not seen this and am not trying to suggest any answers -- mostly I am thinking outloud as to how I would go about this.

Edit:

I've seen other commands like this one, and I'm looking into, but they seem more suitable for servers, and honestly, I'd rather not mess with these settings if I dont know what it does.

The commands would really *not* hurt anything.  Just keep notes on any configuration files you change.  You can always change them back -- even if you have to chroot to do so.

Last edited by ewaller (2016-07-08 15:50:03)

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SgPepper

Member

Registered: 2014-05-16

Posts: 20

Re: Fast downloads kill my connection

Thank you for your answer, I'll keep looking around then. The page you linked is in fact one of the pages I'm reading. Also, reading back /proc/sys/net/core/wmem_max did output the new value.

I'll make sure to post a solution if I find one then.