add EMode to WorkerTheadPool to avoid thread starvation (#492)

- Improvement: Add a new mode to worker thread pools to avoid starvation of workers which could cause long stalls due to other work begin queued up. UE-305498

1 files changed, 13 insertions, 11 deletions

diff --git a/src/zenstore/workspaces.cpp b/src/zenstore/workspaces.cpp
index 0ca2adab2..4e7bd79a3 100644
--- a/src/zenstore/workspaces.cpp
+++ b/src/zenstore/workspaces.cpp
@@ -622,17 +622,19 @@ Workspaces::GetWorkspaceShareChunks(const Oid&							WorkspaceId,
 	for (size_t Index = 0; Index < ChunkRequests.size(); Index++)
 	{
 		WorkLatch.AddCount(1);
-		WorkerPool.ScheduleWork([&, Index]() {
-			auto _ = MakeGuard([&WorkLatch]() { WorkLatch.CountDown(); });
-			try
-			{
-				Chunks[Index] = GetOne(RootPath, *WorkspaceAndShare.second, ChunkRequests[Index]);
-			}
-			catch (const std::exception& Ex)
-			{
-				ZEN_WARN("Exception while fetching chunks, chunk {}: {}", ChunkRequests[Index].ChunkId, Ex.what());
-			}
-		});
+		WorkerPool.ScheduleWork(
+			[&, Index]() {
+				auto _ = MakeGuard([&WorkLatch]() { WorkLatch.CountDown(); });
+				try
+				{
+					Chunks[Index] = GetOne(RootPath, *WorkspaceAndShare.second, ChunkRequests[Index]);
+				}
+				catch (const std::exception& Ex)
+				{
+					ZEN_WARN("Exception while fetching chunks, chunk {}: {}", ChunkRequests[Index].ChunkId, Ex.what());
+				}
+			},
+			WorkerThreadPool::EMode::DisableBacklog);
 	}
 	WorkLatch.CountDown();
 	WorkLatch.Wait();