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Comment by gresrun | Hacker News Reader

If you’re only getting 500qps out of Netty something is deeply wrong with your set up. I’ve written multiple HTTP & socket servers based on Netty (albeit 6+ years ago) and they all could handle 20kqps+.

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Probably a combination of Netty having a small default thread pool size (2*cores) and the benchmark doing something blocking or compute intensive. Tomcat defaults to 200 threads, which would explain the difference.

Edit: Though the page says "The controller does nothing except return a simple 200".

Yeah really doesn't add up - 2 ms to just return a code? What could it possibly be doing with so much time.

The Nagle algorithm interferring with a small packet size, perhaps?

The 2ms delay would be just about right.

I ran the load tests and couldn't explain it either. I adjusted the thread pools, buffer sizes and a bunch of other parameters and couldn't get Netty to scale.

I think Netty tries too hard to be everything to everyone. This makes it really hard to determine how to configure it properly across a bunch of different versions with lots of incompatibilities.

I wrote java-http with the concept of not doing that. It's purpose built for HTTP and high performance.

Once I have some time, I'll publish my Netty setup and let the community bang on it and see if they can beat my RPS. At 65k, it might be hard though. :)

What's the hardware being used for your test? I get 55k RPS with a basic 200 responder with zio-http[0] (which uses Netty) on my i5-6600K, and over 20k RPS for an e2e POST endpoint that does write batching to postgres (committing the insert before responding to all of the clients in the batch with with their individual db generated ids). Postgres, client (vegeta[1]), and the app all on the same machine. I think that was with keep-alive, I think like 256 clients for the basic responder and 1024 for the one that writes to the db. There's a recently merged PR for zio-http that does 1M RPS on whatever machine they test on[2] so Netty can absolutely scale to high RPS.

[0] https://github.com/zio/zio-http

[1] https://github.com/tsenart/vegeta

[2] https://github.com/zio/zio-http/pull/1659

Would love to see your set up!

Sounds good. Once I get the project published, it will include all of the load tests for each server as well as the setup and code for it all. Might be a couple of weeks or so, but it will be a separate GH project. Something like java-http-performance.

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