This is now how a fork-join pool works basically. Please read the docs about managing blocking: https://doc.akka.io/docs/akka/2.5/scala/dispatchers.html#blocking-needs-careful-management
Tuning the default dispatcher like you’re attempting to here would not have a positive effect by the way. Please simply separate blocking or other behaviours on a different dispatcher, make it a thread-pool one etc. — Konrad `kto.so` Malawski Akka <http://akka.io> @ Lightbend <http://lightbend.com> On 28 September 2017 at 17:35:19, Kilic Ali-Firat (kilic.alifi...@gmail.com) wrote: Scala version : 2.11.7 Akka version : 2.4.17 ----- Hi Akka Team, I'm writing an Akka application using Akka Cluster, Akka Actors and Akka Stream. I have a cluster of 3 nodes : 2 workers and 1 node consuming data from a source. I want three configs files : application.conf, node.worker.conf and node.source.conf. I limit the scope of this message to application.conf and node.worker.conf. Below you can find the content of node.worker.conf and application.conf : akka.cluster.roles = [workers] akka { loglevel = "INFO" loglevel = ${?FGS_AKKA_LOG_LEVEL} actor { provider = "akka.cluster.ClusterActorRefProvider" default-dispatcher { # This will be used if you have set "executor = "fork-join-executor"" fork-join-executor { # Min number of threads to cap factor-based parallelism number to parallelism-min = 1 # The parallelism factor is used to determine thread pool size using the # following formula: ceil(available processors * factor). Resulting size # is then bounded by the parallelism-min and parallelism-max values. parallelism-factor = 1 # Max number of threads to cap factor-based parallelism number to parallelism-max = 8 } throughput = 1024 } } remote { enabled-transports = ["akka.remote.netty.tcp"] netty.tcp { hostname = ${clustering.node-ip} port = ${clustering.node-port} bind-hostname = "0.0.0.0" bind-port = ${clustering.node-port} } } cluster { seed-nodes = [ "akka.tcp://"${clustering.cluster.name}"@"${clustering.fst-seed-node -ip}":"${clustering.fst-seed-node-port} "akka.tcp://"${clustering.cluster.name}"@"${clustering.snd-seed-node -ip}":"${clustering.snd-seed-node-port} ] } } clustering { # Choose the same need port for the seed nodes. Seed nodes must be on # different machines. fst-seed-node-port = 2551 fst-seed-node-port = ${?FGS_FIRST_SEED_NODE_PORT} snd-seed-node-port = 2552 snd-seed-node-port = ${?FGS_SECOND_SEED_NODE_PORT} fst-seed-node-ip="localhost" fst-seed-node-ip=${?FGS_FIRST_SEED_NODE_IP} snd-seed-node-ip="localhost" snd-seed-node-ip=${?FGS_SECOND_SEED_NODE_IP} // Must be the public IP node-ip = ${?FGS_CLUSTER_NODE_IP} node-port = ${?FGS_CLUSTER_NODE_PORT} cluster.name = "FGS" } I tried to tune some settings of my default-dispatcher : I want to limit the number of threads in the thread pool to 8. My laptop has 8 cores, this is why I put the parallelism-factor to 1.0 But looking with jvisualm the number allocated threads, I got more than expected (I attached a screenshot). When I expected to have only 8 threads, I get it 21. This is how I create my ActorSystem : val akkaConfig = ConfigFactory.load() val actorSystemConfig = (ConfigFactory parseResources "node.worker.conf") .withFallback(akkaConfig) .resolve() lazy val actorSystemName = akkaConfig getString clusterNamePath implicit val system = ActorSystem(actorSystemName, actorSystemConfig) Am I wrong when creating my Actor System ? -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. To unsubscribe from this group and stop receiving emails from it, send an email to akka-user+unsubscr...@googlegroups.com. To post to this group, send email to akka-user@googlegroups.com. Visit this group at https://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout. -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. To unsubscribe from this group and stop receiving emails from it, send an email to akka-user+unsubscr...@googlegroups.com. To post to this group, send email to akka-user@googlegroups.com. Visit this group at https://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.