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Old 12-24-2006, 06:54 AM   #1
rylan76
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Registered: Apr 2004
Location: Potchefstroom, South Africa
Distribution: Fedora 17 - 3.3.4-5.fc17.x86_64
Posts: 1,497

Rep: Reputation: 90
Random loss of connectivity with dropped packets indicated - ?


Hi all

I've got a new install of Fc6, and /sbin/ifconfig reports dropped TX packets:

[root@StefanLinux rylan]# /sbin/ifconfig
eth0 Link encap:Ethernet HWaddr 00:16:E6:5D:F3:65
inet addr:169.254.255.20 Bcast:169.254.255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1933 errors:0 dropped:0 overruns:0 frame:0
TX packets:1822 errors:0 dropped:17 overruns:0 carrier:0
collisions:0 txqueuelen:2000
RX bytes:645517 (630.3 KiB) TX bytes:314713 (307.3 KiB)
Interrupt:153 Base address:0x9000

My connection goes down every now and then (totally randomly -sometimes twice in a minute, sometimes once every half-hour) and my linux box goes "mute". It can't be pinged, nor can it ping out. XP works fine for hours (dual-booting on the same machine). So I'm sure its Linux, not hardware or my network infrastructure here. Other PC's using XP on the same LAN and the same router to get to the internet have no problems.

What causes dropped packets? How can I fix it so none are dropped?
 
Old 12-24-2006, 11:34 AM   #2
rylan76
Senior Member
 
Registered: Apr 2004
Location: Potchefstroom, South Africa
Distribution: Fedora 17 - 3.3.4-5.fc17.x86_64
Posts: 1,497

Original Poster
Rep: Reputation: 90
Hi guys

Just thought I'd report that it seems I've got this mitigated further or maybe licked in total!

It seems the buffer overflows I was experiencing was caused by a too long transmission queue length. I've changed the transmission queue length to 500 instead of the default 1000 by doing:

/sbin/ifconfig eth0 169.254.255.20 netmask 255.255.255.0 broadcast 169.254.255.255 txqueuelen 500 up

Now, if I run ifconfig I no longer have dropped packets:

eth0 Link encap:Ethernet HWaddr 00:16:E6:5D:F3:65
inet addr:169.254.255.20 Bcast:169.254.255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1701246 errors:0 dropped:0 overruns:0 frame:0
TX packets:1135670 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:2447542857 (2.2 GiB) TX bytes:100667936 (96.0 MiB)
Interrupt:177 Base address:0x9000

Previously I had dropped packets indicated with a queue length of 1000. For the record, this is on a Gigabyte GA945PL-S3 motherboard with FC6 with a custom compiled 2.6.18.1 kernel with the

03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 01)

NIC as indicated by lspci. I'm running the RealTek Linux driver for this card.

I further also massively increased certain buffersizes that were autotuned by the kernel. I've not tested if the queue length was the deciding factor (it works, so I want to leave it as it is!) but I also did this:

echo 98886080 > /proc/sys/net/core/wmem_max
echo 98886080 > /proc/sys/net/core/rmem_max
echo 98886080 > /proc/sys/net/core/wmem_default
echo 98886080 > /proc/sys/net/core/rmem_default
echo 32767 > /proc/sys/net/core/optmem_max
echo 256 > /proc/sys/net/core/somaxconn
echo 2000 > /proc/sys/net/core/netdev_max_backlog

echo 0 > /proc/sys/net/ipv4/tcp_timestamps
echo 1 > /proc/sys/net/ipv4/tcp_sack
echo 1 > /proc/sys/net/ipv4/tcp_window_scaling

echo 26244 786432 1048576 > /proc/sys/net/ipv4/tcp_mem
echo 43960 4194304 8194304 > /proc/sys/net/ipv4/tcp_rmem
echo 43960 4194304 8194304 > /proc/sys/net/ipv4/tcp_wmem

Hope this helps somebody else?
 
Old 12-31-2006, 04:58 AM   #3
rylan76
Senior Member
 
Registered: Apr 2004
Location: Potchefstroom, South Africa
Distribution: Fedora 17 - 3.3.4-5.fc17.x86_64
Posts: 1,497

Original Poster
Rep: Reputation: 90
Failure

Ok, I'm giving up trying to get this card to work in Linux.

It seems the r1000v5.tgz driver from Realtek is buggy for the 8168B/8111 Gigabit Ethernet adapter on the GA-945PL-S3 motherboard. The problems kept persisting, and the NIC is unusable so regularly under 2.6.18.1 it just as well could be absent from the system.

I disabled it in the BIOS and put in a Realtek RTL-8139 card in an open PCI slot and I'm now using that with the 2.6.18.1 kernel on my GA-945PL-S3 motherboard. Everything's fine now.

It seems like the Realtek RTL-8168B/8111 Gigabit LAN adapter is unusable with 2.6.18.1 with the Realtek r1000v5.tgz driver, at least until Realtek maybe releases a new version that will fix the ENOBUFS bug on the current driver for the RTL-8168B/8111 provided by Realtek.
 
  


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