CPUs at 100% when running `runAll` on sample projects

Expected Behavior

CPUs usage should be to a minimum when idle.

Actual Behavior

From the gitter channel:

Trying out the basic hello world example, as well as chirper, I do notice however that running the app with “activator runAll” uses 100% of a cpu core (on OS X at least). Anyone else notice that?

I could reproduce it, and it seems to be that activator is partly to blame for using 100% on all CPUs, since if I’m running sbt runAll less CPUs are spinning (but I still get 4 out of 8 CPUs at 100%). I did a quick investigation, and I think the embedded Cassandra server is to blame for most of the remaining waste of CPUs cycles.

Reproducible Test Case

• Run activator runAll and notice how all CPUs are busy at 100%. Compare with sbt runAll where less CPUs cycles seem to be wasted (and the waste seems to be due the next item). This seems an activator template issue.
• Run sbt lagomCassandraStart on the chirper activator template and notice how many CPUs (in my case (4 out of 8) are extremely busy, doing nothing 😃

[ghost]

For impatient noobies like me: until the netty dependency gets fixed setting up standalone cassandra lowers CPU consumptions and takes about 5 minutes

//from documentation lagomCassandraEnabled in ThisBuild := false lagomCassandraPort in ThisBuild := 9042

[dotta]

@stephenirven Indeed. There is a PR open that will fix that https://github.com/lagom/activator-lagom-java/pull/13