EthScheduler additions (#767)

Add the services thread pool and a computation thread pool to the
EthScheduler.

* Services are long running, sequential, and infrequently start tasks
  such as Full Sync and Fast Sync.
* Computations are short and high CPU intensity tasks such as ECDSA
  signature extractions and POW validation.  The intent is that each
  runnable represents one such extraction and the extractions from a
  block are saturated across available processing power.  These
  computations should have zero dependencies outside their object and
  thread.
Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

consensus/ibftlegacy/src/main/java/tech/pegasys/pantheon/consensus/ibftlegacy/protocol/Istanbul64ProtocolManager.java

@@ -32,8 +32,16 @@ public class Istanbul64ProtocolManager extends EthProtocolManager {
       final int networkId,
       final boolean fastSyncEnabled,
       final int syncWorkers,
-      final int txWorkers) {
+      final int txWorkers,
-    super(blockchain, worldStateArchive, networkId, fastSyncEnabled, syncWorkers, txWorkers);
+      final int computationWorkers) {
+    super(
+        blockchain,
+        worldStateArchive,
+        networkId,
+        fastSyncEnabled,
+        syncWorkers,
+        txWorkers,
+        computationWorkers);
   }
 
   @Override

ethereum/eth/src/main/java/tech/pegasys/pantheon/ethereum/eth/manager/EthProtocolManager.java

@@ -95,6 +95,7 @@ public class EthProtocolManager implements ProtocolManager, MinedBlockObserver {
       final boolean fastSyncEnabled,
       final int syncWorkers,
       final int txWorkers,
+      final int computationWorkers,
       final int requestLimit) {
     this(
         blockchain,
@@ -102,7 +103,7 @@ public class EthProtocolManager implements ProtocolManager, MinedBlockObserver {
         networkId,
         fastSyncEnabled,
         requestLimit,
-        new EthScheduler(syncWorkers, txWorkers));
+        new EthScheduler(syncWorkers, txWorkers, computationWorkers));
   }
 
   public EthProtocolManager(
@@ -111,7 +112,8 @@ public class EthProtocolManager implements ProtocolManager, MinedBlockObserver {
       final int networkId,
       final boolean fastSyncEnabled,
       final int syncWorkers,
-      final int txWorkers) {
+      final int txWorkers,
+      final int computationWorkers) {
     this(
         blockchain,
         worldStateArchive,
@@ -119,6 +121,7 @@ public class EthProtocolManager implements ProtocolManager, MinedBlockObserver {
         fastSyncEnabled,
         syncWorkers,
         txWorkers,
+        computationWorkers,
         DEFAULT_REQUEST_LIMIT);
   }
 

ethereum/eth/src/main/java/tech/pegasys/pantheon/ethereum/eth/manager/EthScheduler.java

@@ -44,8 +44,11 @@ public class EthScheduler {
   protected final ExecutorService syncWorkerExecutor;
   protected final ScheduledExecutorService scheduler;
   protected final ExecutorService txWorkerExecutor;
+  private final ExecutorService servicesExecutor;
+  private final ExecutorService computationExecutor;
 
-  EthScheduler(final int syncWorkerCount, final int txWorkerCount) {
+  EthScheduler(
+      final int syncWorkerCount, final int txWorkerCount, final int computationWorkerCount) {
     this(
         Executors.newFixedThreadPool(
             syncWorkerCount,
@@ -62,16 +65,29 @@ public class EthScheduler {
             txWorkerCount,
             new ThreadFactoryBuilder()
                 .setNameFormat(EthScheduler.class.getSimpleName() + "-Transactions-%d")
+                .build()),
+        Executors.newCachedThreadPool(
+            new ThreadFactoryBuilder()
+                .setNameFormat(EthScheduler.class.getSimpleName() + "-Services-%d")
+                .build()),
+        Executors.newFixedThreadPool(
+            computationWorkerCount,
+            new ThreadFactoryBuilder()
+                .setNameFormat(EthScheduler.class.getSimpleName() + "-Computation-%d")
                 .build()));
   }
 
   protected EthScheduler(
       final ExecutorService syncWorkerExecutor,
       final ScheduledExecutorService scheduler,
-      final ExecutorService txWorkerExecutor) {
+      final ExecutorService txWorkerExecutor,
+      final ExecutorService servicesExecutor,
+      final ExecutorService computationExecutor) {
     this.syncWorkerExecutor = syncWorkerExecutor;
     this.scheduler = scheduler;
     this.txWorkerExecutor = txWorkerExecutor;
+    this.servicesExecutor = servicesExecutor;
+    this.computationExecutor = computationExecutor;
   }
 
   public <T> CompletableFuture<T> scheduleSyncWorkerTask(
@@ -101,12 +117,20 @@ public class EthScheduler {
     return promise;
   }
 
-  public Future<?> scheduleSyncWorkerTask(final Runnable command) {
+  public void scheduleSyncWorkerTask(final Runnable command) {
-    return syncWorkerExecutor.submit(command);
+    syncWorkerExecutor.submit(command);
+  }
+
+  public void scheduleTxWorkerTask(final Runnable command) {
+    txWorkerExecutor.submit(command);
+  }
+
+  CompletableFuture<Void> scheduleServiceTask(final Runnable service) {
+    return CompletableFuture.runAsync(service, servicesExecutor);
   }
 
-  public Future<?> scheduleTxWorkerTask(final Runnable command) {
+  <T> CompletableFuture<T> scheduleComputationTask(final Supplier<T> computation) {
-    return txWorkerExecutor.submit(command);
+    return CompletableFuture.supplyAsync(computation, computationExecutor);
   }
 
   public CompletableFuture<Void> scheduleFutureTask(
@@ -194,25 +218,46 @@ public class EthScheduler {
     if (stopped.compareAndSet(false, true)) {
       LOG.trace("Stopping " + getClass().getSimpleName());
       syncWorkerExecutor.shutdown();
+      txWorkerExecutor.shutdown();
       scheduler.shutdown();
+      servicesExecutor.shutdown();
+      computationExecutor.shutdown();
       shutdown.countDown();
     } else {
       LOG.trace("Attempted to stop already stopped " + getClass().getSimpleName());
     }
   }
 
-  public void awaitStop() throws InterruptedException {
+  void awaitStop() throws InterruptedException {
     shutdown.await();
     if (!syncWorkerExecutor.awaitTermination(2L, TimeUnit.MINUTES)) {
       LOG.error("{} worker executor did not shutdown cleanly.", this.getClass().getSimpleName());
       syncWorkerExecutor.shutdownNow();
       syncWorkerExecutor.awaitTermination(2L, TimeUnit.MINUTES);
     }
+    if (!txWorkerExecutor.awaitTermination(2L, TimeUnit.MINUTES)) {
+      LOG.error(
+          "{} transaction worker executor did not shutdown cleanly.",
+          this.getClass().getSimpleName());
+      txWorkerExecutor.shutdownNow();
+      txWorkerExecutor.awaitTermination(2L, TimeUnit.MINUTES);
+    }
     if (!scheduler.awaitTermination(2L, TimeUnit.MINUTES)) {
       LOG.error("{} scheduler did not shutdown cleanly.", this.getClass().getSimpleName());
       scheduler.shutdownNow();
       scheduler.awaitTermination(2L, TimeUnit.MINUTES);
     }
+    if (!servicesExecutor.awaitTermination(2L, TimeUnit.MINUTES)) {
+      LOG.error("{} services executor did not shutdown cleanly.", this.getClass().getSimpleName());
+      servicesExecutor.shutdownNow();
+      servicesExecutor.awaitTermination(2L, TimeUnit.MINUTES);
+    }
+    if (!computationExecutor.awaitTermination(2L, TimeUnit.MINUTES)) {
+      LOG.error(
+          "{} computation executor did not shutdown cleanly.", this.getClass().getSimpleName());
+      computationExecutor.shutdownNow();
+      computationExecutor.awaitTermination(2L, TimeUnit.MINUTES);
+    }
     LOG.trace("{} stopped.", this.getClass().getSimpleName());
   }
 
@@ -222,7 +267,7 @@ public class EthScheduler {
     return promise;
   }
 
-  public <T> void failAfterTimeout(final CompletableFuture<T> promise) {
+  <T> void failAfterTimeout(final CompletableFuture<T> promise) {
     failAfterTimeout(promise, defaultTimeout);
   }
 

ethereum/eth/src/main/java/tech/pegasys/pantheon/ethereum/eth/sync/SynchronizerConfiguration.java

@@ -29,9 +29,9 @@ public class SynchronizerConfiguration {
   private static final Logger LOG = LogManager.getLogger();
 
   // TODO: Determine reasonable defaults here
-  public static int DEFAULT_PIVOT_DISTANCE_FROM_HEAD = 500;
+  public static final int DEFAULT_PIVOT_DISTANCE_FROM_HEAD = 500;
-  public static float DEFAULT_FULL_VALIDATION_RATE = .1f;
+  public static final float DEFAULT_FULL_VALIDATION_RATE = .1f;
-  public static int DEFAULT_FAST_SYNC_MINIMUM_PEERS = 5;
+  public static final int DEFAULT_FAST_SYNC_MINIMUM_PEERS = 5;
   private static final Duration DEFAULT_FAST_SYNC_MAXIMUM_PEER_WAIT_TIME = Duration.ofMinutes(5);
   private static final int DEFAULT_WORLD_STATE_HASH_COUNT_PER_REQUEST = 200;
   private static final int DEFAULT_WORLD_STATE_REQUEST_PARALLELISM = 10;
@@ -62,6 +62,7 @@ public class SynchronizerConfiguration {
   private final int maxTrailingPeers;
   private final int downloaderParallelism;
   private final int transactionsParallelism;
+  private final int computationParallelism;
 
   private SynchronizerConfiguration(
       final SyncMode requestedSyncMode,
@@ -82,7 +83,8 @@ public class SynchronizerConfiguration {
       final long trailingPeerBlocksBehindThreshold,
       final int maxTrailingPeers,
       final int downloaderParallelism,
-      final int transactionsParallelism) {
+      final int transactionsParallelism,
+      final int computationParallelism) {
     this.requestedSyncMode = requestedSyncMode;
     this.fastSyncPivotDistance = fastSyncPivotDistance;
     this.fastSyncFullValidationRate = fastSyncFullValidationRate;
@@ -102,6 +104,7 @@ public class SynchronizerConfiguration {
     this.maxTrailingPeers = maxTrailingPeers;
     this.downloaderParallelism = downloaderParallelism;
     this.transactionsParallelism = transactionsParallelism;
+    this.computationParallelism = computationParallelism;
   }
 
   /**
@@ -147,7 +150,8 @@ public class SynchronizerConfiguration {
         trailingPeerBlocksBehindThreshold,
         maxTrailingPeers,
         downloaderParallelism,
-        transactionsParallelism);
+        transactionsParallelism,
+        computationParallelism);
   }
 
   public static Builder builder() {
@@ -232,6 +236,10 @@ public class SynchronizerConfiguration {
     return transactionsParallelism;
   }
 
+  public int computationParallelism() {
+    return computationParallelism;
+  }
+
   /**
    * The rate at which blocks should be fully validated during fast sync. At a rate of 1f, all
    * blocks are fully validated. At rates less than 1f, a subset of blocks will undergo light-weight
@@ -274,6 +282,7 @@ public class SynchronizerConfiguration {
     private int maxTrailingPeers = Integer.MAX_VALUE;
     private int downloaderParallelism = 2;
     private int transactionsParallelism = 2;
+    private int computationParallelism = Runtime.getRuntime().availableProcessors();
 
     public Builder fastSyncPivotDistance(final int distance) {
       fastSyncPivotDistance = distance;
@@ -350,6 +359,11 @@ public class SynchronizerConfiguration {
       return this;
     }
 
+    public Builder computationParallelism(final int computationParallelism) {
+      this.computationParallelism = computationParallelism;
+      return this;
+    }
+
     public SynchronizerConfiguration build() {
       return new SynchronizerConfiguration(
           syncMode,
@@ -370,7 +384,8 @@ public class SynchronizerConfiguration {
           trailingPeerBlocksBehindThreshold,
           maxTrailingPeers,
           downloaderParallelism,
-          transactionsParallelism);
+          transactionsParallelism,
+          computationParallelism);
     }
   }
 }

ethereum/eth/src/test/java/tech/pegasys/pantheon/ethereum/eth/manager/DeterministicEthScheduler.java

@@ -28,7 +28,12 @@ public class DeterministicEthScheduler extends EthScheduler {
   }
 
   public DeterministicEthScheduler(final TimeoutPolicy timeoutPolicy) {
-    super(new MockExecutorService(), new MockScheduledExecutor(), new MockExecutorService());
+    super(
+        new MockExecutorService(),
+        new MockScheduledExecutor(),
+        new MockExecutorService(),
+        new MockExecutorService(),
+        new MockExecutorService());
     this.timeoutPolicy = timeoutPolicy;
   }
 

ethereum/eth/src/test/java/tech/pegasys/pantheon/ethereum/eth/manager/EthProtocolManagerTest.java

@@ -80,6 +80,8 @@ import org.junit.BeforeClass;
 import org.junit.Test;
 import org.mockito.ArgumentCaptor;
 
+// NullPointerExceptions on optional.get() will result in test failures anyway
+@SuppressWarnings("OptionalGetWithoutIsPresent")
 public final class EthProtocolManagerTest {
 
   private static Blockchain blockchain;
@@ -101,7 +103,8 @@ public final class EthProtocolManagerTest {
   @Test
   public void disconnectOnUnsolicitedMessage() {
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final MessageData messageData =
           BlockHeadersMessage.create(Collections.singletonList(blockchain.getBlockHeader(1).get()));
       final MockPeerConnection peer = setupPeer(ethManager, (cap, msg, conn) -> {});
@@ -113,7 +116,8 @@ public final class EthProtocolManagerTest {
   @Test
   public void disconnectOnFailureToSendStatusMessage() {
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final MessageData messageData =
           BlockHeadersMessage.create(Collections.singletonList(blockchain.getBlockHeader(1).get()));
       final MockPeerConnection peer =
@@ -126,7 +130,8 @@ public final class EthProtocolManagerTest {
   @Test
   public void disconnectOnWrongChainId() {
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final MessageData messageData =
           BlockHeadersMessage.create(Collections.singletonList(blockchain.getBlockHeader(1).get()));
       final MockPeerConnection peer =
@@ -150,7 +155,8 @@ public final class EthProtocolManagerTest {
   @Test
   public void disconnectOnWrongGenesisHash() {
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final MessageData messageData =
           BlockHeadersMessage.create(Collections.singletonList(blockchain.getBlockHeader(1).get()));
       final MockPeerConnection peer =
@@ -174,7 +180,8 @@ public final class EthProtocolManagerTest {
   @Test(expected = ConditionTimeoutException.class)
   public void doNotDisconnectOnValidMessage() {
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final MessageData messageData =
           GetBlockBodiesMessage.create(Collections.singletonList(gen.hash()));
       final MockPeerConnection peer = setupPeer(ethManager, (cap, msg, conn) -> {});
@@ -190,7 +197,8 @@ public final class EthProtocolManagerTest {
   public void respondToGetHeaders() throws ExecutionException, InterruptedException {
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final long startBlock = 5L;
       final int blockCount = 5;
       final MessageData messageData =
@@ -223,7 +231,7 @@ public final class EthProtocolManagerTest {
     final int limit = 5;
     try (final EthProtocolManager ethManager =
         new EthProtocolManager(
-            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, limit)) {
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1, limit)) {
       final long startBlock = 5L;
       final int blockCount = 10;
       final MessageData messageData =
@@ -254,7 +262,8 @@ public final class EthProtocolManagerTest {
   public void respondToGetHeadersReversed() throws ExecutionException, InterruptedException {
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final long endBlock = 10L;
       final int blockCount = 5;
       final MessageData messageData = GetBlockHeadersMessage.create(endBlock, blockCount, 0, true);
@@ -284,7 +293,8 @@ public final class EthProtocolManagerTest {
   public void respondToGetHeadersWithSkip() throws ExecutionException, InterruptedException {
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final long startBlock = 5L;
       final int blockCount = 5;
       final int skip = 1;
@@ -317,7 +327,8 @@ public final class EthProtocolManagerTest {
       throws ExecutionException, InterruptedException {
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final long endBlock = 10L;
       final int blockCount = 5;
       final int skip = 1;
@@ -371,7 +382,8 @@ public final class EthProtocolManagerTest {
   public void respondToGetHeadersPartial() throws ExecutionException, InterruptedException {
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final long startBlock = blockchain.getChainHeadBlockNumber() - 1L;
       final int blockCount = 5;
       final MessageData messageData =
@@ -402,7 +414,8 @@ public final class EthProtocolManagerTest {
   public void respondToGetHeadersEmpty() throws ExecutionException, InterruptedException {
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final long startBlock = blockchain.getChainHeadBlockNumber() + 1;
       final int blockCount = 5;
       final MessageData messageData =
@@ -430,7 +443,8 @@ public final class EthProtocolManagerTest {
   public void respondToGetBodies() throws ExecutionException, InterruptedException {
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       // Setup blocks query
       final long startBlock = blockchain.getChainHeadBlockNumber() - 5;
       final int blockCount = 2;
@@ -475,7 +489,7 @@ public final class EthProtocolManagerTest {
     final int limit = 5;
     try (final EthProtocolManager ethManager =
         new EthProtocolManager(
-            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, limit)) {
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1, limit)) {
       // Setup blocks query
       final int blockCount = 10;
       final long startBlock = blockchain.getChainHeadBlockNumber() - blockCount;
@@ -518,7 +532,8 @@ public final class EthProtocolManagerTest {
   public void respondToGetBodiesPartial() throws ExecutionException, InterruptedException {
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       // Setup blocks query
       final long expectedBlockNumber = blockchain.getChainHeadBlockNumber() - 1;
       final BlockHeader header = blockchain.getBlockHeader(expectedBlockNumber).get();
@@ -555,7 +570,8 @@ public final class EthProtocolManagerTest {
   public void respondToGetReceipts() throws ExecutionException, InterruptedException {
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       // Setup blocks query
       final long startBlock = blockchain.getChainHeadBlockNumber() - 5;
       final int blockCount = 2;
@@ -599,7 +615,7 @@ public final class EthProtocolManagerTest {
     final int limit = 5;
     try (final EthProtocolManager ethManager =
         new EthProtocolManager(
-            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, limit)) {
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1, limit)) {
       // Setup blocks query
       final int blockCount = 10;
       final long startBlock = blockchain.getChainHeadBlockNumber() - blockCount;
@@ -641,7 +657,8 @@ public final class EthProtocolManagerTest {
   public void respondToGetReceiptsPartial() throws ExecutionException, InterruptedException {
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       // Setup blocks query
       final long blockNumber = blockchain.getChainHeadBlockNumber() - 5;
       final BlockHeader header = blockchain.getBlockHeader(blockNumber).get();
@@ -680,7 +697,7 @@ public final class EthProtocolManagerTest {
     final WorldStateArchive worldStateArchive = protocolContext.getWorldStateArchive();
 
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, worldStateArchive, 1, true, 1, 1)) {
+        new EthProtocolManager(blockchain, worldStateArchive, 1, true, 1, 1, 1)) {
       // Setup node data query
 
       final List<BytesValue> expectedResults = new ArrayList<>();
@@ -722,7 +739,8 @@ public final class EthProtocolManagerTest {
   @Test
   public void newBlockMinedSendsNewBlockMessageToAllPeers() {
     final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1);
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1);
 
     // Define handler to validate response
     final PeerSendHandler onSend = mock(PeerSendHandler.class);
@@ -785,7 +803,8 @@ public final class EthProtocolManagerTest {
 
     final CompletableFuture<Void> done = new CompletableFuture<>();
     try (final EthProtocolManager ethManager =
-        new EthProtocolManager(blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1)) {
+        new EthProtocolManager(
+            blockchain, protocolContext.getWorldStateArchive(), 1, true, 1, 1, 1)) {
       final long startBlock = 1L;
       final int requestedBlockCount = 13;
       final int receivedBlockCount = 2;
@@ -831,7 +850,10 @@ public final class EthProtocolManagerTest {
     final ExecutorService worker = mock(ExecutorService.class);
     final ScheduledExecutorService scheduled = mock(ScheduledExecutorService.class);
     final ExecutorService transactions = mock(ExecutorService.class);
-    final EthScheduler ethScheduler = new EthScheduler(worker, scheduled, transactions);
+    final ExecutorService services = mock(ExecutorService.class);
+    final ExecutorService computations = mock(ExecutorService.class);
+    final EthScheduler ethScheduler =
+        new EthScheduler(worker, scheduled, transactions, services, computations);
 
     // Create the fake TransactionMessage to feed to the EthManager.
     final BlockDataGenerator gen = new BlockDataGenerator(1);

ethereum/eth/src/test/java/tech/pegasys/pantheon/ethereum/eth/manager/EthSchedulerShutdownTest.java

@@ -0,0 +1,138 @@
+/*
+ * Copyright 2018 ConsenSys AG.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+package tech.pegasys.pantheon.ethereum.eth.manager;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.time.Duration;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class EthSchedulerShutdownTest {
+
+  private EthScheduler ethScheduler;
+  private ExecutorService syncWorkerExecutor;
+  private ScheduledExecutorService scheduledExecutor;
+  private ExecutorService txWorkerExecutor;
+  private ExecutorService servicesExecutor;
+  private ExecutorService computationExecutor;
+
+  @Before
+  public void setup() {
+    scheduledExecutor = Executors.newSingleThreadScheduledExecutor();
+    syncWorkerExecutor = Executors.newSingleThreadExecutor();
+    txWorkerExecutor = Executors.newSingleThreadExecutor();
+    servicesExecutor = Executors.newSingleThreadExecutor();
+    computationExecutor = Executors.newSingleThreadExecutor();
+    ethScheduler =
+        new EthScheduler(
+            syncWorkerExecutor,
+            scheduledExecutor,
+            txWorkerExecutor,
+            servicesExecutor,
+            computationExecutor);
+  }
+
+  @Test
+  public void shutdown_syncWorkerShutsDown() throws InterruptedException {
+    final MockEthTask task = new MockEthTask(1);
+
+    ethScheduler.scheduleSyncWorkerTask(task::executeTask);
+    ethScheduler.stop();
+
+    assertThat(syncWorkerExecutor.isShutdown()).isTrue();
+    assertThat(syncWorkerExecutor.isTerminated()).isFalse();
+
+    task.countDown();
+    ethScheduler.awaitStop();
+
+    assertThat(syncWorkerExecutor.isShutdown()).isTrue();
+    assertThat(syncWorkerExecutor.isTerminated()).isTrue();
+  }
+
+  @Test
+  public void shutdown_scheduledWorkerShutsDown() throws InterruptedException {
+    final MockEthTask task = new MockEthTask(1);
+
+    ethScheduler.scheduleFutureTask(task::executeTask, Duration.ofMillis(1));
+    ethScheduler.stop();
+
+    assertThat(scheduledExecutor.isShutdown()).isTrue();
+    assertThat(scheduledExecutor.isTerminated()).isFalse();
+
+    task.countDown();
+    ethScheduler.awaitStop();
+
+    assertThat(scheduledExecutor.isShutdown()).isTrue();
+    assertThat(scheduledExecutor.isTerminated()).isTrue();
+  }
+
+  @Test
+  public void shutdown_txWorkerShutsDown() throws InterruptedException {
+    final MockEthTask task = new MockEthTask(1);
+
+    ethScheduler.scheduleTxWorkerTask(task::executeTask);
+    ethScheduler.stop();
+
+    assertThat(txWorkerExecutor.isShutdown()).isTrue();
+    assertThat(txWorkerExecutor.isTerminated()).isFalse();
+
+    task.countDown();
+    ethScheduler.awaitStop();
+
+    assertThat(txWorkerExecutor.isShutdown()).isTrue();
+    assertThat(txWorkerExecutor.isTerminated()).isTrue();
+  }
+
+  @Test
+  public void shutdown_servicesShutsDown() throws InterruptedException {
+    final MockEthTask task = new MockEthTask(1);
+
+    ethScheduler.scheduleServiceTask(task::executeTask);
+    ethScheduler.stop();
+
+    assertThat(servicesExecutor.isShutdown()).isTrue();
+    assertThat(servicesExecutor.isTerminated()).isFalse();
+
+    task.countDown();
+    ethScheduler.awaitStop();
+
+    assertThat(servicesExecutor.isShutdown()).isTrue();
+    assertThat(servicesExecutor.isTerminated()).isTrue();
+  }
+
+  @Test
+  public void shutdown_computationShutsDown() throws InterruptedException {
+    final MockEthTask task = new MockEthTask(1);
+
+    ethScheduler.scheduleComputationTask(
+        () -> {
+          task.executeTask();
+          return Integer.MAX_VALUE;
+        });
+    ethScheduler.stop();
+
+    assertThat(computationExecutor.isShutdown()).isTrue();
+    assertThat(computationExecutor.isTerminated()).isFalse();
+
+    task.countDown();
+    ethScheduler.awaitStop();
+
+    assertThat(computationExecutor.isShutdown()).isTrue();
+    assertThat(computationExecutor.isTerminated()).isTrue();
+  }
+}

ethereum/eth/src/test/java/tech/pegasys/pantheon/ethereum/eth/manager/MockEthTask.java

@@ -14,28 +14,46 @@ package tech.pegasys.pantheon.ethereum.eth.manager;
 
 import tech.pegasys.pantheon.metrics.noop.NoOpMetricsSystem;
 
+import java.util.concurrent.CountDownLatch;
+
 public class MockEthTask extends AbstractEthTask<Object> {
 
   private boolean executed = false;
+  private CountDownLatch countdown;
 
-  protected MockEthTask() {
+  MockEthTask(final int count) {
     super(NoOpMetricsSystem.NO_OP_LABELLED_TIMER);
+    countdown = new CountDownLatch(count);
+  }
+
+  MockEthTask() {
+    this(0);
   }
 
   @Override
   protected void executeTask() {
+    try {
+      countdown.await();
+    } catch (final InterruptedException ignore) {
+    }
     executed = true;
   }
 
-  public boolean hasBeenStarted() {
+  void countDown() {
+    countdown.countDown();
+  }
+
+  boolean hasBeenStarted() {
     return executed;
   }
 
-  public void complete() {
+  void complete() {
+    if (executed) {
       result.get().complete(null);
     }
+  }
 
-  public void fail() {
+  void fail() {
     result.get().completeExceptionally(new RuntimeException("Failure forced for testing"));
   }
 }

ethereum/eth/src/test/java/tech/pegasys/pantheon/ethereum/eth/transactions/TestNode.java

@@ -104,7 +104,7 @@ public class TestNode implements Closeable {
     final ProtocolContext<Void> protocolContext =
         new ProtocolContext<>(blockchain, worldStateArchive, null);
     final EthProtocolManager ethProtocolManager =
-        new EthProtocolManager(blockchain, worldStateArchive, 1, false, 1, 1);
+        new EthProtocolManager(blockchain, worldStateArchive, 1, false, 1, 1, 1);
 
     final NetworkRunner networkRunner =
         NetworkRunner.builder()

pantheon/src/main/java/tech/pegasys/pantheon/controller/CliquePantheonController.java

@@ -151,7 +151,8 @@ public class CliquePantheonController implements PantheonController<CliqueContex
             networkId,
             fastSyncEnabled,
             syncConfig.downloaderParallelism(),
-            syncConfig.transactionsParallelism());
+            syncConfig.transactionsParallelism(),
+            syncConfig.computationParallelism());
     final SyncState syncState =
         new SyncState(
             protocolContext.getBlockchain(), ethProtocolManager.ethContext().getEthPeers());

pantheon/src/main/java/tech/pegasys/pantheon/controller/IbftLegacyPantheonController.java

@@ -149,7 +149,8 @@ public class IbftLegacyPantheonController implements PantheonController<IbftCont
               networkId,
               fastSyncEnabled,
               syncConfig.downloaderParallelism(),
-              syncConfig.transactionsParallelism());
+              syncConfig.transactionsParallelism(),
+              syncConfig.computationParallelism());
     } else {
       ethSubProtocol = EthProtocol.get();
       ethProtocolManager =
@@ -159,7 +160,8 @@ public class IbftLegacyPantheonController implements PantheonController<IbftCont
               networkId,
               fastSyncEnabled,
               syncConfig.downloaderParallelism(),
-              syncConfig.transactionsParallelism());
+              syncConfig.transactionsParallelism(),
+              syncConfig.computationParallelism());
     }
 
     final SyncState syncState =

pantheon/src/main/java/tech/pegasys/pantheon/controller/IbftPantheonController.java

@@ -165,7 +165,8 @@ public class IbftPantheonController implements PantheonController<IbftContext> {
             networkId,
             fastSyncEnabled,
             syncConfig.downloaderParallelism(),
-            syncConfig.transactionsParallelism());
+            syncConfig.transactionsParallelism(),
+            syncConfig.computationParallelism());
     final SubProtocol ethSubProtocol = EthProtocol.get();
 
     final SyncState syncState =

pantheon/src/main/java/tech/pegasys/pantheon/controller/MainnetPantheonController.java

@@ -126,7 +126,8 @@ public class MainnetPantheonController implements PantheonController<Void> {
                 .orElse(MainnetProtocolSchedule.DEFAULT_CHAIN_ID),
             fastSyncEnabled,
             syncConfig.downloaderParallelism(),
-            syncConfig.transactionsParallelism());
+            syncConfig.transactionsParallelism(),
+            syncConfig.computationParallelism());
     final SyncState syncState =
         new SyncState(
             protocolContext.getBlockchain(), ethProtocolManager.ethContext().getEthPeers());