Undertow properties default values

Question

We're currently tuning our services that uses undertow but we can't find the default values of the following properties:

server.undertow.worker-threads
server.undertow.io-threads

We learned that undertow is using org.xnio.Options in setting-up the threads but can't find any default values.

Answer 1

From https://github.com/undertow-io/undertow/blob/master/core/src/main/java/io/undertow/Undertow.java

...
    ioThreads = Math.max(Runtime.getRuntime().availableProcessors(), 2);
    workerThreads = ioThreads * 8;
...

Answer 2

In the latest version of Spring boot/Undertow, the properties to override are as follows :

Example :

server.undertow.threads.io=50
server.undertow.threads.worker=50