Hi Eric, On Sat, Jan 05, 2013 at 03:18:46PM -0800, Eric Dumazet wrote: > Hi Willy, another good finding during the week end ! ;)
Yes, I wanted to experiment with TFO and stopped on this :-) > 1) This looks like interrupts are spreaded on multiple cpus, and this > give Out Of Order problems with TCP stack. No, I forgot to mention this, I have tried to bind IRQs to a single core, with the server either on the same or another one, but the problem remained. Also, the loopback is much more affected and doesn't use IRQs. And BTW tcpdump on the loopback shouldn't drop that many packets (up to 90% even at low rate). I just noticed something, transferring data using netcat on the loopback doesn't affect tcpdump. So it's likely only the spliced data that are affected. > 2) Another possibility would be that Myri card/driver doesnt like very > well high order pages. It looks like it has not changed much since 3.6 :-/ I really suspect something is wrong with memory allocation. I have tried reverting many patches affecting the mm/ directory just in case but I did not come to anything useful yet. I'm continuing to dig. Thanks, Willy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
