scala - How to profile the time spent for a task in SBT

Question

I'd like to know why sometimes my build is much slower.

So I've decided to measure the time of long-running taks.

When running pure Scala code, it is quite easy to do so:

def myMethod() = {
   val initTime = System.currentTimeMillis
   ...
   val elapsedTime = System.currentTimeMillis-initTime
}

But for tasks like packageBin or compile, whose source code I cannot change, I don't know how to measure it, because I cannot control when someTask.value is run.

Any hint?

Related questions:

• Profiling sbt builds

Answer 1

add -Dsbt.task.timings=true to your JAVA_OPTS when launching sbt