Optimizing Transmission Speed in MSQUIC Multiple Streams

[sai-gvs]

Recently, I started exploring MSQUIC and became particularly interested in utilizing multiple streams for parallel data transmission. To experiment, I opened three streams to send data simultaneously, expecting improved speed. However, I observed that sending data in parallel across these streams actually took longer compared to sequential transmission over a single stream.

To enhance transmission speed across multiple streams, I am considering whether modifications to default settings are required. Are there specific settings that should be modified to optimize performance? Or how can I accelerate the data transmission across these streams efficiently?

[nibanks]

Streams ultimately share the same connection state, which is affixed to a single worker thread at a time. Therefore, increasing the number of streams will not improve throughput with MsQuic. Instead, you'd have to use multiple connections (assuming they are on unique workers) to increase overall throughput (assuming you have the available bandwidth).

[sai-gvs]

Thanks for your response! However, if increasing the number of streams does not improve throughput, what is the advantage of using multiple streams in MsQuic?

[nibanks]

Abstraction. If you are just doing 1 thing, use one stream. But if you are doing N parallel things, you should use N streams to clearly separate them and not have one impact the other.

[anrossi]

For example, if you wrote a QUIC app to transfer files between computers, you could have a single stream with a separator/header between each file sent, or you could have a stream for each file, which makes it easier to implement since you don't have to insert/parse the header between each file. Both approaches take the same amount of time to send the total data, but the latter is easier to implement.