How to configure serenity report thread count? - serenity-bdd

Question

By default Serenity report thread set to 80, during report generation it freezes the machine and I could not find anywhere to configure thread count , as can be seen from below written Test result report, Configured report threads:80, anyone knows how to change it?
Generating HTML Outcome Reports: false
[INFO] Generating test results for 70 tests
[INFO] 149 requirements loaded after 679 ms
[INFO] 149 related requirements found after 679 ms
[INFO] Generating test outcome reports: false
[INFO] Starting generating reports: 769 ms
[INFO] Configured report threads: 80
[INFO] Finished generating test results for 70 tests after 8886 ms
GENERATE CUSTOM REPORTS
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 05:32 min
[INFO] Finished at: 2017-05-13T00:24:30+01:00
[INFO] Final Memory: 52M/1305M

Answer 1

Regarding the default value you are seeing:
By default Serenity report thread set to 80 [...]
You are probably using a quad-core CPU with 8 virtual logical cores (SMT) because the default depends on the number of processors that are available to the Java virtual machine.
Serenity uses that number to initialize the size of the thread pool it uses during report generation.
Here is how to change it:
Create a serenity.properties file
Set the number of threads via the report.threads property
The serenity.properties file is looked up in multiple locations. I recommend that create one for each of your test modules.