I'm trying to find a Java webserver that can handle 10 requests/sec from 1,000 clients. Doesn't need to be good at (or even able to) serve files--I just want to be able to respond to request with some Java code that says "hello world".
I've been assuming that it has to be a NIO based framework that does not have a thread-per-request concurrency model so that I can hanging-GETs with a lot of clients.
So far, I've tried Jetty 7 (which supports a kind of asynchronous Servlet framework for hanging-GETs) and Netty 3 (a NIO framework with a bare-bones webserver). I've tried running both on my iMac and using JMeter on a laptop (same network, but over WiFi) to hammer the server. I can't seem to get more than about 2.5K requests/second out of either.
I suspect I'm doing something wrong.
Things I've tried:
- Playing with VM options. There's lots more to try here. So far I'm just using: -XX:+UserParallelGC -server
- Binding to multiple ports in the server and balancing between them on the client. (Tried this on Netty based on this thread about a bottleneck in the accept thread)
- Increasing the max open files on client and server (ulimit didn't work as expected on the Mac, used "sysctl -w kern.maxfiles=XXXX sysctl -w kern.maxfilesperproc=XXXX" instead)
- Changing the number of clients in the load test; over 300 seems to get lots of errors in both cases. Under 100 hurts the aggregate throughput (no client seems able to get more than 20-30 serial requests/second)
Apache (the default web server on the Mac) can server about 1.5K requests/sec untweaked. I'd expect a "hello world" server that does non-blocking IO to come out farther ahead of Apache than what I'm getting.
I thought maybe JMeter was the bottleneck so I installed Tsung, an Erlang-based, load test tool. It was too difficult to understand their config environment and I wasn't able to get a simple number (aggregate requests/sec) out of it. I'm sure it does this, I just couldn't figure it out and JMeter is so much easier I stuck with it.
Dear Lazy Web, do you have any hints?
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