How to configure a fine tuned thread pool for futures?

How large is Scala's thread pool for futures?

My Scala application makes many millions of future {}s and I wonder if there is anything I can do to optimize them by configuring a thread pool.

Thank you.

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最佳答案

You can specify your own ExecutionContext that your futures will run in, instead of importing the global implicit ExecutionContext.

import java.util.concurrent.Executors
import scala.concurrent._


implicit val ec = new ExecutionContext {
val threadPool = Executors.newFixedThreadPool(1000)


def execute(runnable: Runnable) {
threadPool.submit(runnable)
}


def reportFailure(t: Throwable) {}
}

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This answer is from monkjack, a comment from the accepted answer. However, one can miss this great answer so I'm reposting it here.

implicit val ec = ExecutionContext.fromExecutor(Executors.newFixedThreadPool(10))

If you just need to change the thread pool count, just use the global executor and pass the following system properties.

-Dscala.concurrent.context.numThreads=8 -Dscala.concurrent.context.maxThreads=8

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best way to specify threadpool in scala futures:

implicit val ec = new ExecutionContext {
val threadPool = Executors.newFixedThreadPool(conf.getInt("5"));
override def reportFailure(cause: Throwable): Unit = {};
override def execute(runnable: Runnable): Unit = threadPool.submit(runnable);
def shutdown() = threadPool.shutdown();
}

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class ThreadPoolExecutionContext(val executionContext: ExecutionContext)


object ThreadPoolExecutionContext {


val executionContextProvider: ThreadPoolExecutionContext = {
try {
val executionContextExecutor: ExecutionContextExecutor = ExecutionContext.fromExecutor(Executors.newFixedThreadPool(25))
new ThreadPoolExecutionContext(executionContextExecutor)
} catch {
case exception: Exception => {
Log.error("Failed to create thread pool", exception)
throw exception
}
}
}
}