Add test for distribution of tasks

2 files changed, 16 insertions, 2 deletions

diff --git a/searchlib/src/tests/common/sequencedtaskexecutor/sequencedtaskexecutor_test.cpp b/searchlib/src/tests/common/sequencedtaskexecutor/sequencedtaskexecutor_test.cpp
index 558d24551a8..fcc7fd7300d 100644
--- a/searchlib/src/tests/common/sequencedtaskexecutor/sequencedtaskexecutor_test.cpp
+++ b/searchlib/src/tests/common/sequencedtaskexecutor/sequencedtaskexecutor_test.cpp
@@ -234,6 +234,17 @@ TEST("require that you get correct number of executors") {
     EXPECT_EQUAL(7u, seven.getNumExecutors());
 }
 
+TEST("require that you distribute well") {
+    SequencedTaskExecutor seven(7);
+    EXPECT_EQUAL(7u, seven.getNumExecutors());
+    EXPECT_EQUAL(97u, seven.getComponentHashSize());
+    EXPECT_EQUAL(0u, seven.getComponentEffectiveHashSize());
+    for (uint32_t id=0; id < 1000; id++) {
+        EXPECT_EQUAL((id%97)%7, seven.getExecutorId(id).getId());
+    }
+    EXPECT_EQUAL(97u, seven.getComponentHashSize());
+    EXPECT_EQUAL(97u, seven.getComponentEffectiveHashSize());
+}
 
 }
 
diff --git a/searchlib/src/vespa/searchlib/common/isequencedtaskexecutor.h b/searchlib/src/vespa/searchlib/common/isequencedtaskexecutor.h
index d1318a2b71c..109e8319148 100644
--- a/searchlib/src/vespa/searchlib/common/isequencedtaskexecutor.h
+++ b/searchlib/src/vespa/searchlib/common/isequencedtaskexecutor.h
@@ -71,7 +71,6 @@ public:
      * Wrap lambda function into a task and schedule it to be run.
      * Caller must ensure that pointers and references are valid and
      * call sync before tearing down pointed to/referenced data.
-     * All tasks must be scheduled from same thread.
      *
      * @param componentId   component id
      * @param function      function to be wrapped in a task and later executed
@@ -86,7 +85,6 @@ public:
      * Wrap lambda function into a task and schedule it to be run.
      * Caller must ensure that pointers and references are valid and
      * call sync before tearing down pointed to/referenced data.
-     * All tasks must be scheduled from same thread.
      *
      * @param id        executor id
      * @param function  function to be wrapped in a task and later executed
@@ -95,6 +93,11 @@ public:
     void execute(ExecutorId id, FunctionType &&function) {
         executeTask(id, vespalib::makeLambdaTask(std::forward<FunctionType>(function)));
     }
+    /**
+     * For testing only
+     */
+    uint32_t getComponentHashSize() const { return _component2Id.size(); }
+    uint32_t getComponentEffectiveHashSize() const { return _nextId; }
 private:
     mutable std::vector<uint8_t> _component2Id;
     mutable std::mutex           _mutex;