Pool buffers in wspb/wsjson

[nhooyr]

Opportunities for optimization available in

• wspb
• wsjson
• Dial bufio read writers.

[Dreamacro]

Will sync.Pool can be passthrough to Dial?

gorilla/websocket implementation with a private struct (https://github.com/gorilla/websocket/blob/6a67f44b69004415802d2e678e483065b8fff6c8/conn.go#L480)

I prefer pool.Get().([]byte) to share with other io.CopyBuffer.

[nhooyr]

I think it's unlikely I'll take an approach similar to gorilla/websocket. This is an internal implementation detail, I don't want to expose it unless absolutely necessary. At least until #65 is resolved.

[Dreamacro]

In my case, I use websocket to transfer other protocol traffic. For the sake of maintainability, I keep nesting net.Conn like Russian Doll. There are allocate []byte each level, so I want to share a pool with whole application.

[nhooyr]

I'm sorry I don't understand your use case. Can you elaborate on why you're nesting net.Conn and why you're allocating a []byte at each level?

[coadler]

Thoughts on https://github.com/valyala/bytebufferpool?

[nhooyr]

@coadler Would prefer to avoid the dependency on a library outside of the stdlib

See the benchmarks linked by that library https://omgnull.github.io/go-benchmark/buffer/

sync.Pool is only 4.5ns slower so its best to just use it instead.

The only buffers we can reuse are the bufio.Read/Writers and the buffers used by the wspb/wsjson subpackages used by client conns. The net/http hijacker always allocates for the server.

I've already tackled reuse of the bufio read/writers in #81

@coadler if you have time, would appreciate you implementing reuse of buffers for wspb/wsjson

[nhooyr]

The write side for wsjson already reuses buffers because it uses json.NewEncoder which uses a sync.Pool underneath. We'd have to switch json.NewDecoder to use json.Unmarshal if we want buffer reuse and for the wspb package, we'll have to use the proto.Buffer type for reuse.

[nhooyr]

Definitely a good idea to have some benchmarks as well.

[coadler]

Will tackle this tonight

[nhooyr]

@coadler I think its best that instead of modifying wsjson and wspb, we just modify the Read method on the conn to use a buffer pool only if the received message is greater than 128 bytes.