On Mon, 23 Nov 2020 14:22:31 +0000 Thomas Karlsson wrote: > Hello, > > There is a special queue handling in macvlan.c for broadcast and > multicast packages that was arbitrarily set to 1000 in commit > 07d92d5cc977a7fe1e683e1d4a6f723f7f2778cb . While this is probably > sufficient for most uses cases it is insufficient to support high > packet rates. I currently have a setup with 144 000 multicast packets > incoming per second (144 different live audio RTP streams) and suffer > very frequent packet loss. With unicast this is not an issue and I > can in addition to the 144kpps load the macvlan interface with > another 450mbit/s using iperf. > > In order to verify that the queue is the problem I edited the define > to 100000 and recompiled the kernel module. After replacing it with > rmmod/insmod I get 0 packet loss (measured over 2 days where I before > had losses every other second or so) and can also load an additional > 450 mbit/s multicast traffic using iperf without losses. So basically > no change in performance between unicast/multicast when it comes to > lost packets on my machine. > > I think It would be best if this queue length was configurable > somehow. Either an option when creating the macvlan (like how > bridge/passthrough/etc are set) or at least when loading the module > (for instance by using a config in /etc/modprobe.d). One size does > not fit all in this situation.
The former please. You can add a netlink attribute, should be reasonably straightforward. The other macvlan attrs are defined under "MACVLAN section" in if_link.h.
