Re: forcedeth ipv6 mcast packet loss

From: Christian Tramnitz
Date: Thu Sep 24 2009 - 05:22:19 EST

Joachim Worringen wrote:
It's either the driver or the hardware - I suspect the latter. I experienced significant problems with Nvidia Ethernet hardware and the nforcedeth driver under load, in many machines.

My recommendation is to use another NIC if possible. I then switchted to Intel, which worked flawlessly in the same machines.

Alternatively, you could try to increase the kernel buffers for network packets as in your case, you seem to loose the packets further up:
# sysctl -w net.core.rmem_max=8388608
# sysctl -w net.core.wmem_max=8388608
# sysctl -w net.core.rmem_default=65536
# sysctl -w net.core.wmem_default=65536

There are buffers for ipv4 like you can tune with
# sysctl -w net.ipv4.tcp_rmem='4096 87380 8388608'
- I don't know if this is the same for ipv6.


I already raised the kernel buffers, with no success. I doubt its a hardware issue (unless its a general design flaw) because I have two identical boards with the same problem and also read about similar problems other users had (with forcedeth).
Changing the NIC is unfortunately not a long-term option, its onboard and there is no PCI(e) slot. Using a USB NIC (which is my current workaround) I cannot netboot and I really don't want to run this box with two NICs in the long run...
Especially since I do *not* have any problems with high bandwidth ipv4/unicast traffic, so I really think this is a driver issue that can be fixed. Does anyone have a pointer to the forcedeth code that could be relevant in this ipv6/mcast setup?

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