dynamic_buffer with higher number than initial buffer won't be dynamic

[edgurgel]

Hi team,

I think there is an issue when we set dynamic_buffer to something like {4096, 65356} if the initial socket buffer is a much lower number like 1460.

Because the buffer is not set initially to 4096 (from what I could understand) the moving average never gets close to 4096 making the buffer essentially static.

I assumed initially that the first number would set the initial socket buffer.

Please let me know if I misunderstood something and feel free to close the ticket if that's the case!

Thanks in advance.

[essen]

You're correct that the buffer size must be set separately. Originally I made this for RabbitMQ which has non-HTTP protocols and for those we set buffer initially to a very low value (128) until the user has authenticated. In Cowboy and HTTP we don't benefit from that.

I don't know if there's benefits to not setting the buffer value automatically during init, perhaps we should revise that. I suppose doing it in init means the socket that had a default/original buffer size has to be resized before any data gets received, it's likely slightly better to just let the user configure buffer directly.