Yes, that was it. Many thanks! Should I just use polling, which works fine, or is there something one can do about the interrupt issue?
-Richard On 17 October 2016 at 22:05, Matthew Dillon <dil...@backplane.com> wrote: > That kinda sounds like an interrupt issue, in which case I suggest turning > polling on for both interfaces. ifconfig <blah> polling ought to do it. If > that fixes the problem, then it is definitely interrupt-related. > > -Matt > > On Mon, Oct 17, 2016 at 12:52 PM, Richard Nyberg <rnyb...@murmeldjur.se> > wrote: >> >> Thanks again for your suggestions. >> >> Actually it's much stranger than I thought. While troubleshooting I >> had this configuration: >> >> df (em0) -> switch <- desktop >> >> No other devices or network interfaces were connected. In this >> configuration there was no problem at all with latency. I then plugged >> in the cable with internet acces like below: >> >> internet <- (re0) df (em0) -> switch <- desktop >> >> In this configuration the latency problems immediately showed. The fun >> thing is that when I unplugged the re0 interface again the em0 >> interface stopped responding at all, until I put the cable back to >> re0. Then em0 was back but with latency problems. >> >> Another data point is that while I downloaded a large file at speed >> from the internet via df to my desktop in the above configuration and >> pinged from the desktop to df at the same time, the latency problems >> were gone. Until the download was finished and they started again. >> >> -Richard >> >> On 16 October 2016 at 19:14, Matthew Dillon <dil...@backplane.com> wrote: >> > Look for a packet loop on the interface. Use tcpdump on the interface >> > to >> > see if there are excess packets being generated from somewhere. There >> > are >> > numerous things that can blow up a LAN. The most common being that a >> > switch >> > port is wired to loop back into the LAN. >> > >> > -Matt >> > >> > On Sun, Oct 16, 2016 at 9:17 AM, Justin Sherrill >> > <jus...@shiningsilence.com> >> > wrote: >> >> >> >> On Sun, Oct 16, 2016 at 11:49 AM, Richard Nyberg >> >> <rnyb...@murmeldjur.se> >> >> wrote: >> >> > Thanks! >> >> > >> >> > Here are some more datapoints. >> >> >> >> I think the only constant at this point is the internal interface on >> >> the DragonFly system. If you hook the em0 interface that's currently >> >> internal on the DragonFly machine up to your Internet link (i.e. >> >> reverse which interface is internal or external), does it still >> >> perform badly? >> >> >> >> If it doesn't work well, then that interface is bad. I'd be >> >> surprised, cause I've seen network ports go bad very rarely, but it's >> >> possible. Plus, I don't have any other ideas. >> > >> > > >