Ubuntu

15.10 64-bit wired network very slow after 2-5 minutes

Asked by LEGOManiac

I have clean installed 15.10 64-bit but I'm finding that when I first boot up, wired network speed is the same as it was when I was running 32-bit 14.10, however, after a few minutes the network speed slows to a crawl such that I can't even stream music off a local server and copying the file to my local machine so I can play it takes 6-8 minutes for one mp3. This is on a gigabit network. It worked beautifully on the previous OS release. I have no idea if this is a bug introduced in 15.10 or if it has something to do the fact that I'm now running 64 bit drivers. If I load the old 32-bit 14.10 live CD, network speed is normal.

Things I've tried based on other posts (but I haven't seen anyone complain about 15.10, so these 'fixes' may be out of date as none of them worked anyway):

Set the MTU rate to 1492 from "automatic"

Set IPv6 to "ignore"

Added the following lines to sysctl.conf:
# The following lines were added because the network interface was extremely sl$
# as per http://www.noobslab.com/2012/05/disable-ipv6-if-your-internet-is.html
# IPv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

As I say, nothing has worked so far.

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actionparsnip (andrew-woodhead666) said : 		#1

What is the output of:

sudo lshw -C network;lsb_release -a;uname -a

Thanks

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LEGOManiac (bzflaglegomaniac) said : 		#2

Thank you for coming to my rescue (again)...

  *-network
       description: Ethernet interface
       product: 3c905C-TX/TX-M [Tornado]
       vendor: 3Com Corporation
       physical id: 1
       bus info: pci@0000:04:01.0
       logical name: enp4s1
       version: 78
       serial: 00:01:03:ba:31:d2
       size: 100Mbit/s
       capacity: 100Mbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=3c59x duplex=full ip=192.168.6.29 latency=32 link=yes maxlatency=10 mingnt=10 multicast=yes port=MII speed=100Mbit/s
       resources: irq:17 ioport:d000(size=128) memory:fb220000-fb22007f memory:fb200000-fb21ffff
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 15.10
Release: 15.10
Codename: wily
Linux LEGOManiacPC 4.2.0-18-generic #22-Ubuntu SMP Fri Nov 6 18:25:50 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Also, in investigating this myself, I see this from ifconfig:

enp4s1 Link encap:Ethernet HWaddr 00:01:03:ba:31:d2
          inet addr:192.168.6.29 Bcast:192.168.6.255 Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
          RX packets:6130215 errors:0 dropped:5676 overruns:9445 frame:0
          TX packets:30377665 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1671063813 (1.6 GB) TX bytes:41423270248 (41.4 GB)
          Interrupt:17 Base address:0x2000

A) I would swear that under the previous installation, this was called eth0. I'm not sure if enp4s1 has any significance.
B) I'm extremely puzzled by the 1.6GB received vs. 41.4GB transmitted ratio. This is most certainly not a file server. If anything, I would have expected it to be the other way around.

Revision history for this message
actionparsnip (andrew-woodhead666) said : 		#3

I found this:

https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.20/+bug/94186

Revision history for this message
LEGOManiac (bzflaglegomaniac) said : 		#4

I'm going to close this one. The bug report explained why my NIC was connecting at 100Mb/s instead of 1Gb/s, but didn't resolve the problem of why the speed slows down dramatically under the 64bit Ubuntu but not the 32Bit version.

It did get me thinking, and I post this for anyone else who might have replaced their NIC because they thought the motherboard NIC had failed....

Some months ago, my motherboard's network interface stopped working altogether. This was under Lubuntu 14.10, 32 bit. I figured it was the motherboard, as it isn't uncommon for them to fail, so I went out and bought a 1GB ethernet controller (3Com) and when it worked, I figured that confirmed the suspected motherboard problem.

Today I went out to replace the now problematic 3Com network card but couldn't find one locally. I was about to buy on online when I had a hunch:

I re-enabled the motherboard's network interface in the BIOS, plugged the cable in and booted into Lubuntu 15.10, 64bit and I am now back on-line at full speed. I'll have to see if this fails over time.

Revision history for this message
LEGOManiac (bzflaglegomaniac) said : 		#5

Well, it's been a week and the motherboard's previously "broken" network adapter is still going strong under Lubuntu 15.10/64bit.

I'm going to try and close this ticket, even though the problem with 15.10 and the 3Com ethernet adapter was never resolved.

Revision history for this message
LEGOManiac (bzflaglegomaniac) said : 		#6

Well that's interesting; exactly how does one close and unresolved problem?

Revision history for this message
LEGOManiac (bzflaglegomaniac) said : 		#7

Nevermind. It turns out that adding a comment doesn't give the "Problem Solved" button, but "I still need an answer" does.