[erlang-questions] Distribution: small packets

Danil Zagoskin z@REDACTED
Tue Jul 8 21:20:27 CEST 2014


There is enormous packet-per-second in my distributed erlang setup.

Under heavy load in single distribution socket and in one direction tcpdump
shows rates like 40..100 packets with tcp-push flag set per millisecond.
Size of majority of packets is 47..112 bytes while MTU on network interface
is 8950 (jumbo-frames).

If distribution driver aggregated messages to fit MTU it would be 100 times
less packets in network.
Given cluster of 3 nodes (very small) and both directions we get about
extra 300K PPS which causes packet drops and tcp retransmits (thus
increasing latency a lot).

Is it possible to make erlang distribution push packets less often (one
millisecond would be enough for me)?

I'm sure this is not of net ticks because tracing on dist_util:con_loop
process shows quite low {_, tick} message rate.

Erlang/OTP version used is 17.0.

Danil Zagoskin | z@REDACTED
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