diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 17bf5b909..d752722ce 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -119,12 +119,16 @@ jobs:
         run: ./bin/inv_wrapper.sh dev.cc faabric_tests
       - name: "Run tests"
         run: ./bin/inv_wrapper.sh tests
+        timeout-minutes: 10
 
   dist-tests:
     if: github.event.pull_request.draft == false
     needs: [conan-cache]
-    runs-on: ubuntu-latest
+    runs-on: self-hosted
     env:
+      # Make a unique per-job cluster name, so that different instances can
+      # run in parallel
+      COMPOSE_PROJECT_NAME: faabric-gha-${{ github.job }}-${{ github.run_id }}-${{ github.run_attempt }}
       CONAN_CACHE_MOUNT_SOURCE: ~/.conan/
     steps:
       # --- Code update ---
@@ -136,9 +140,13 @@ jobs:
         run: ./dist-test/build.sh
       - name: "Run the distributed tests"
         run: ./dist-test/run.sh
+        timeout-minutes: 10
       - name: "Print planner logs"
         if: always()
         run: docker compose logs planner
+      - name: "Chown all files to avoid docker-related root-owned files"
+        if: always()
+        run: sudo chown -R $(id -u):$(id -g) .
 
   examples:
     if: github.event.pull_request.draft == false
diff --git a/include/faabric/mpi/MpiWorld.h b/include/faabric/mpi/MpiWorld.h
index 8f9cb918c..97fb24f18 100644
--- a/include/faabric/mpi/MpiWorld.h
+++ b/include/faabric/mpi/MpiWorld.h
@@ -28,7 +28,7 @@ namespace faabric::mpi {
 // as the broker already has mocking capabilities
 std::vector<MpiMessage> getMpiMockedMessages(int sendRank);
 
-typedef faabric::util::FixedCapacityQueue<MpiMessage> InMemoryMpiQueue;
+typedef faabric::util::SpinLockQueue<MpiMessage> InMemoryMpiQueue;
 
 class MpiWorld
 {
@@ -184,8 +184,6 @@ class MpiWorld
 
     std::shared_ptr<InMemoryMpiQueue> getLocalQueue(int sendRank, int recvRank);
 
-    long getLocalQueueSize(int sendRank, int recvRank);
-
     void overrideHost(const std::string& newHost);
 
     double getWTime();
diff --git a/include/faabric/util/queue.h b/include/faabric/util/queue.h
index 6d89aab18..9f9e2f164 100644
--- a/include/faabric/util/queue.h
+++ b/include/faabric/util/queue.h
@@ -4,6 +4,7 @@
 #include <faabric/util/locks.h>
 #include <faabric/util/logging.h>
 
+#include <boost/lockfree/spsc_queue.hpp>
 #include <condition_variable>
 #include <queue>
 #include <readerwriterqueue/readerwritercircularbuffer.h>
@@ -215,6 +216,48 @@ class FixedCapacityQueue
     moodycamel::BlockingReaderWriterCircularBuffer<T> mq;
 };
 
+// High-performance, spin-lock single-producer, single-consumer queue. This
+// queue spin-locks, so use at your own risk!
+template<typename T>
+class SpinLockQueue
+{
+  public:
+    void enqueue(T& value, long timeoutMs = DEFAULT_QUEUE_TIMEOUT_MS)
+    {
+        while (!mq.push(value)) {
+            ;
+        };
+    }
+
+    T dequeue(long timeoutMs = DEFAULT_QUEUE_TIMEOUT_MS)
+    {
+        T value;
+
+        while (!mq.pop(value)) {
+            ;
+        }
+
+        return value;
+    }
+
+    long size()
+    {
+        throw std::runtime_error("Size for fast queue unimplemented!");
+    }
+
+    void drain()
+    {
+        while (mq.pop()) {
+            ;
+        }
+    }
+
+    void reset() { ; }
+
+  private:
+    boost::lockfree::spsc_queue<T, boost::lockfree::capacity<1024>> mq;
+};
+
 class TokenPool
 {
   public:
diff --git a/src/mpi/MpiWorld.cpp b/src/mpi/MpiWorld.cpp
index 9839d7f96..cc8705dfc 100644
--- a/src/mpi/MpiWorld.cpp
+++ b/src/mpi/MpiWorld.cpp
@@ -1568,13 +1568,6 @@ int MpiWorld::getIndexForRanks(int sendRank, int recvRank) const
     return index;
 }
 
-long MpiWorld::getLocalQueueSize(int sendRank, int recvRank)
-{
-    const std::shared_ptr<InMemoryMpiQueue>& queue =
-      getLocalQueue(sendRank, recvRank);
-    return queue->size();
-}
-
 double MpiWorld::getWTime()
 {
     double t = faabric::util::getTimeDiffMillis(creationTime);
diff --git a/tests/test/mpi/test_multiple_mpi_worlds.cpp b/tests/test/mpi/test_multiple_mpi_worlds.cpp
index a6e74f0b5..a1062e81b 100644
--- a/tests/test/mpi/test_multiple_mpi_worlds.cpp
+++ b/tests/test/mpi/test_multiple_mpi_worlds.cpp
@@ -155,29 +155,6 @@ TEST_CASE_METHOD(MultiWorldMpiTestFixture,
     worldB.send(
       rankA1, rankA2, BYTES(messageData.data()), MPI_INT, messageData.size());
 
-    SECTION("Test queueing")
-    {
-        // Check for world A
-        REQUIRE(worldA.getLocalQueueSize(rankA1, rankA2) == 1);
-        REQUIRE(worldA.getLocalQueueSize(rankA2, rankA1) == 0);
-        REQUIRE(worldA.getLocalQueueSize(rankA1, 0) == 0);
-        REQUIRE(worldA.getLocalQueueSize(rankA2, 0) == 0);
-        const std::shared_ptr<InMemoryMpiQueue>& queueA2 =
-          worldA.getLocalQueue(rankA1, rankA2);
-        MpiMessage actualMessage = queueA2->dequeue();
-        // checkMessage(actualMessage, worldId, rankA1, rankA2, messageData);
-
-        // Check for world B
-        REQUIRE(worldB.getLocalQueueSize(rankA1, rankA2) == 1);
-        REQUIRE(worldB.getLocalQueueSize(rankA2, rankA1) == 0);
-        REQUIRE(worldB.getLocalQueueSize(rankA1, 0) == 0);
-        REQUIRE(worldB.getLocalQueueSize(rankA2, 0) == 0);
-        const std::shared_ptr<InMemoryMpiQueue>& queueA2B =
-          worldB.getLocalQueue(rankA1, rankA2);
-        actualMessage = queueA2B->dequeue();
-        // checkMessage(actualMessage, worldId, rankA1, rankA2, messageData);
-    }
-
     SECTION("Test recv")
     {
         MPI_Status status{};