avoid busy loop (#12157)

Author: kakaiu

fdbclient/ServerKnobs.cpp

@@ -391,6 +391,7 @@ void ServerKnobs::initialize(Randomize randomize, ClientKnobs* clientKnobs, IsSi
 	init( MANIFEST_COUNT_MAX_PER_BULKLOAD_TASK,                   10 ); if (isSimulated) MANIFEST_COUNT_MAX_PER_BULKLOAD_TASK = deterministicRandom()->randomInt(1, 11);
 	init( BULKLOAD_SIM_FAILURE_INJECTION,                      false ); if (isSimulated) BULKLOAD_SIM_FAILURE_INJECTION = true;
 	init( DD_BULKLOAD_POWER_OF_D_RATIO,                          2.0 ); if (isSimulated) DD_BULKLOAD_POWER_OF_D_RATIO = deterministicRandom()->randomInt(1, 11);
+	init( DD_BULKLOAD_TASK_SUBMISSION_INTERVAL_SEC,             0.01 );
 
 	// BulkDumping
 	init( DD_BULKDUMP_SCHEDULE_MIN_INTERVAL_SEC,                 5.0 ); if( randomize && BUGGIFY ) DD_BULKDUMP_SCHEDULE_MIN_INTERVAL_SEC = deterministicRandom()->random01() * 10 + 1;

fdbclient/include/fdbclient/ServerKnobs.h

@@ -418,6 +418,8 @@ class SWIFT_CXX_IMMORTAL_SINGLETON_TYPE ServerKnobs : public KnobsImpl<ServerKno
 	double DD_BULKLOAD_POWER_OF_D_RATIO; // When selecting the dest team, DD randomly chooses 1/D portion of all valid
 	                                     // teams as the candidates and the DD selects the team with the minimal number
 	                                     // of ongoing tasks from the candidates as the dest team.
+	double DD_BULKLOAD_TASK_SUBMISSION_INTERVAL_SEC; // the seconds that the bulkload task submitter has to wait
+	                                                 // between two tasks
 	bool CC_ENFORCE_USE_UNFIT_DD_IN_SIM; // Set for CC to enforce to use an unfit DD in the simulation. This knob takes
 	                                     // effect only in the simulation.
 	bool DISABLE_AUDIT_STORAGE_FINAL_REPLICA_CHECK_IN_SIM; // Set to disable audit storage replica check in the

fdbserver/DataDistribution.actor.cpp

@@ -1941,7 +1941,7 @@ ACTOR Future<Void> scheduleBulkLoadJob(Reference<DataDistributor> self, Promise<
 					                                    self->bulkLoadJobManager.get().manifestLocalTempFolder,
 					                                    manifestEntries,
 					                                    errorOut));
-					wait(yield()); // Avoid busy loop
+					wait(delay(SERVER_KNOBS->DD_BULKLOAD_TASK_SUBMISSION_INTERVAL_SEC)); // Avoid busy loop
 				}
 				ASSERT(beginKey == res[i + 1].key);
 			}