RFE: Performance Issue about transportc HOT 3 CLOSED

Performance patches & benchmark results are available.

TL;DR

the performance could be pretty decent, but having multiple Data Channel opened on the same Peer Connection may result in undefined behaviors, including performance degradation, broken pipe, latency spike, etc.

from transportc.

Benchmark Result

Single Data Channel (Connection)

 conn_test.go:300: 1KB Test, 10000 round(s), Bw: 42MB/s, Lat: 24.11us
 conn_test.go:300: 2KB Test, 10000 round(s), Bw: 60MB/s, Lat: 33.84us
 conn_test.go:300: 4KB Test, 10000 round(s), Bw: 77MB/s, Lat: 52.85us
 conn_test.go:300: 8KB Test, 10000 round(s), Bw: 92MB/s, Lat: 88.21us

Multiple Data Channels (Connections)

conn_test.go:401: 10 Connections, 1KB Test, 1000 round(s) each, Bw: 46MB/s, Lat: 216us
conn_test.go:401: 10 Connections, 2KB Test, 1000 round(s) each, Bw: 61MB/s, Lat: 326us
conn_test.go:401: 10 Connections, 4KB Test, 1000 round(s) each, Bw: 75MB/s, Lat: 533us
conn_test.go:401: 10 Connections, 8KB Test, 1000 round(s) each, Bw: 89MB/s, Lat: 895us
conn_test.go:401: 20 Connections, 1KB Test, 500 round(s) each, Bw: 47MB/s, Lat: 432us
conn_test.go:401: 20 Connections, 2KB Test, 500 round(s) each, Bw: 60MB/s, Lat: 673us
conn_test.go:401: 20 Connections, 4KB Test, 500 round(s) each, Bw: 72MB/s, Lat: 1109us
conn_test.go:401: 20 Connections, 8KB Test, 500 round(s) each, Bw: 88MB/s, Lat: 1822us

from transportc.

Longer Analysis

Using multiple data channels (connections) DOES NOT introduce theoretical performance difference in terms of throughput, but brings NEGATIVE impact on latency: Multiplexing 10 connections on 1 WebRTC PeerConnection makes the latency per each message transmitted 10x higher comparing to using single data channel. And multiplexing 20 connections results in 20x higher latency.

In addition, multiplexing connections makes WebRTC PeerConnection unstable. With increased number of connections over a single PeerConnection, the chance of SCTP stream breaks and the chance of message transmission having a much greater latency (10x~100x) both increase.

Recommendation: If no compelling reason, should avoid using more connection over one PeerConnection if possible.

from transportc.