README.md

Vert.x C10K

This example project contains a very basic http server which demonstrates the basics that are need to build a Vert.x server which can handle 10k concurrent connections.

Test Server

The example program starts Vert.x and deploys multiple http verticles.

Noteworthy aspects:

• The netty-transport-native-epoll library adds epoll support.

• HttpServer options improve connection handling

options
    .setPort(SERVER_PORT)
    .setHost(SERVER_HOST)
    .setCompressionSupported(true)
    .setHandle100ContinueAutomatically(true)
    .setTcpFastOpen(true)
    .setTcpNoDelay(true)
    .setTcpQuickAck(true);

• VertxOptions to prefer native transports

VertxOptions vertxOptions = new VertxOptions();
vertxOptions.setPreferNativeTransport(true);

• Deploy multiple verticles

DeploymentOptions options = new DeploymentOptions();
int nVerticles = Runtime.getRuntime().availableProcessors() * 2;
options.setInstances(nVerticles);

Build & Run

mvn clean package
java -jar target/vertx-c10k-example-0.0.1-SNAPSHOT.jar

API Endpoints

• GET http://localhost:8080/0k - Returns empty response

• GET http://localhost:8080/static/4k - Returns fixed 4k response

• GET http://localhost:8080/static/8k - Returns fixed 8k response

• GET http://localhost:8080/static/64k - Return fixed 64k response

• GET http://localhost:8080/cached/4k - Returns 4k response from caffeine cache

• GET http://localhost:8080/cached/8k - Returns 8k response from caffeine cache

• GET http://localhost:8080/cached/64k - Return 64k response from caffeine cache

• GET http://localhost:8080/jcs/4k - Return 4k response from JCS disk based cache

• GET http://localhost:8080/sendFile/test - Returns response which uses NIO sendfile() call.

• POST http://localhost:8080/upload - Upload a file, empty response will be returned

Metrics

• GET http://localhost:8081/metrics - Return micrometer metrics for prometheus

Kernel Options

# Increase amount of open files. This will allow the creation of more network sockets.
sysctl -w fs.file-max=110000
sysctl -w fs.nr_open=110000
ulimit -n 110000

# Increase tcp buffers
sysctl -w net.ipv4.tcp_mem="100000000 100000000 100000000"

# Increase socket connection limit
sysctl -w net.core.somaxconn=10000

# Increase backlog size for tcp connections in SYN state
sysctl -w net.ipv4.tcp_max_syn_backlog=10000

Tests

via wrk

./wrk -c10000 -d32s -t16 http://localhost:8080/static/4k

via apache benchmark

ab -n 200000 -c 10000 http://localhost:8080/static/4k

Example Results

• On Intel i7 7700k @ Debian Linux 5.10.0-8-amd64
• OpenJDK Runtime Environment (build 11.0.12+7-post-Debian-2)

# wrk -c10000 -d32s -t16 http://localhost:8080/static/4k
Running 32s test @ http://localhost:8080/static/4k
  16 threads and 10000 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    99.31ms   46.74ms 435.93ms   68.46%
    Req/Sec     6.37k   578.54    20.15k    75.24%
  3247189 requests in 32.10s, 12.51GB read
Requests/sec: 101156.41
Transfer/sec:    399.10MB

Disclaimer

Please note that the results should not be used as a performance reference. The server response is static. The tests are run locally. There are many other factors which will affect real world performance.

Resources

• http://www.kegel.com/c10k.html
• Real world HTTP performance benchmarking, lessons learned by Julien Viet