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by dmm 1621 days ago
TCP provides backpressure but depending on it to provide backpressure over the internet will greatly increase latency, in my experience.

In one application I was streaming jpeg frames over a websocket and by the time the server application experienced backpressure there were 10s of seconds of messages buffered between the server and client. So the message rate would eventually settle into a rate the connection could sustain but messages would take 10+ seconds to reach the client.
1 comments
dragontamer 1621 days ago
Perhaps that sounds like a good time to use TCP_CORK, or TCP_NODELAY flags.

Or, perhaps you need to tune the TCP-Window to your application.

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dmm 1620 days ago
> TCP_CORK, or TCP_NODELAY flags

I'm sending large messages, ~150 kibibytes, so much larger than a typical internet packet. So I'm not sure Nagle's algorithm is the problem.

> tune the TCP-Window to your application.

This is a possibility. I already had to increase wmem_max to handle fast udp connections.

I'll try to put together a minimal test case when I get the chance.

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