Merge pull request ceph#58194 from bill-scales/fix_unittest_rocksdb_option

test/objectstore/TestRocksdbOptionParse.cc: Fix race hazard

Reviewed-by: Igor Fedotov <[email protected]>
Reviewed-by: Kefu Chai <[email protected]>

Author: tchaikov

src/test/objectstore/TestRocksdbOptionParse.cc

@@ -55,11 +55,20 @@ TEST(RocksDBOption, interpret) {
   ASSERT_EQ(0, r);
   ASSERT_TRUE(db->compact_on_mount);
   //check thread pool setting
-  options.env->SleepForMicroseconds(100000);
   std::vector<rocksdb::ThreadStatus> thread_list;
-  status = options.env->GetThreadList(&thread_list);
-  ASSERT_TRUE(status.ok());
-
+  /* Race hazard - rocksdb does not register its threads until they start
+   * running, and only guarantees the threads have been created before
+   * returning. We need to be prepared to wait for the scheduler to
+   * run the threads to avoid false positives.
+   */
+  for (int attempt = 0; attempt < 50; attempt++) {
+    options.env->SleepForMicroseconds(100000);
+    status = options.env->GetThreadList(&thread_list);
+    ASSERT_TRUE(status.ok());
+    if (thread_list.size() >= 15u) {
+      break;
+    }
+  }
   int num_high_pri_threads = 0;
   int num_low_pri_threads = 0;
   for (vector<rocksdb::ThreadStatus>::iterator it = thread_list.begin();