only disable backlog scheduling when downloaded payload is not on disk (#741)

3 files changed, 15 insertions, 7 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0a210c6e2..26199bcd9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 - Improvement: Reduce maximum size per chunk to read to reduce disk contention
 - Improvement: Reduce default size for block store chunk read window when iterating chunks
 - Improvement: Increase timeout before warning on slow shut down of zenserver
+- Improvement: Revise logic for enabling work backlog during `zen builds download`
 - Bugfix: Restore `/health/log` and `/health/info` endpoint functionality
 
 ## 5.7.19
diff --git a/src/zenremotestore/builds/buildstorageoperations.cpp b/src/zenremotestore/builds/buildstorageoperations.cpp
index 5368c7df4..26968efc1 100644
--- a/src/zenremotestore/builds/buildstorageoperations.cpp
+++ b/src/zenremotestore/builds/buildstorageoperations.cpp
@@ -1335,7 +1335,7 @@ BuildsOperationUpdateFolder::Execute(FolderContent& OutLocalFolderState)
 											FilteredWrittenBytesPerSecond);
 						}
 					},
-					WorkerThreadPool::EMode::DisableBacklog);
+					WorkerThreadPool::EMode::EnableBacklog);
 			}
 
 			std::unique_ptr<CloneQueryInterface> CloneQuery;
@@ -1596,7 +1596,8 @@ BuildsOperationUpdateFolder::Execute(FolderContent& OutLocalFolderState)
 													}
 												}
 											},
-											WorkerThreadPool::EMode::DisableBacklog);
+											OnDiskPath.empty() ? WorkerThreadPool::EMode::DisableBacklog
+															   : WorkerThreadPool::EMode::EnableBacklog);
 									}
 								});
 						}
@@ -1785,7 +1786,8 @@ BuildsOperationUpdateFolder::Execute(FolderContent& OutLocalFolderState)
 													}
 												}
 											},
-											WorkerThreadPool::EMode::DisableBacklog);
+											BlockChunkPath.empty() ? WorkerThreadPool::EMode::DisableBacklog
+																   : WorkerThreadPool::EMode::EnableBacklog);
 									}
 								}
 							}
@@ -3189,6 +3191,8 @@ BuildsOperationUpdateFolder::WriteLooseChunk(const uint32_t					  RemoteChunkInd
 															{
 																FilteredDownloadedBytesPerSecond.Stop();
 															}
+															IoBufferFileReference FileRef;
+															bool				  EnableBacklog = Payload.GetFileReference(FileRef);
 															AsyncWriteDownloadedChunk(m_Options.ZenFolderPath,
 																					  RemoteChunkIndex,
 																					  std::move(ChunkTargetPtrs),
@@ -3198,7 +3202,8 @@ BuildsOperationUpdateFolder::WriteLooseChunk(const uint32_t					  RemoteChunkInd
 																					  SequenceIndexChunksLeftToWriteCounters,
 																					  WritePartsComplete,
 																					  TotalPartWriteCount,
-																					  FilteredWrittenBytesPerSecond);
+																					  FilteredWrittenBytesPerSecond,
+																					  EnableBacklog);
 														});
 								  }
 							  });
@@ -4309,7 +4314,8 @@ BuildsOperationUpdateFolder::AsyncWriteDownloadedChunk(const std::filesystem::pa
 													   std::span<std::atomic<uint32_t>> SequenceIndexChunksLeftToWriteCounters,
 													   std::atomic<uint64_t>&			WritePartsComplete,
 													   const uint64_t					TotalPartWriteCount,
-													   FilteredRate&					FilteredWrittenBytesPerSecond)
+													   FilteredRate&					FilteredWrittenBytesPerSecond,
+													   bool								EnableBacklog)
 {
 	ZEN_TRACE_CPU("AsyncWriteDownloadedChunk");
 
@@ -4427,7 +4433,7 @@ BuildsOperationUpdateFolder::AsyncWriteDownloadedChunk(const std::filesystem::pa
 				}
 			}
 		},
-		WorkerThreadPool::EMode::DisableBacklog);
+		EnableBacklog ? WorkerThreadPool::EMode::EnableBacklog : WorkerThreadPool::EMode::DisableBacklog);
 }
 
 void
diff --git a/src/zenremotestore/include/zenremotestore/builds/buildstorageoperations.h b/src/zenremotestore/include/zenremotestore/builds/buildstorageoperations.h
index 47f402e15..6304159ae 100644
--- a/src/zenremotestore/include/zenremotestore/builds/buildstorageoperations.h
+++ b/src/zenremotestore/include/zenremotestore/builds/buildstorageoperations.h
@@ -378,7 +378,8 @@ private:
 								   std::span<std::atomic<uint32_t>>									 SequenceIndexChunksLeftToWriteCounters,
 								   std::atomic<uint64_t>&											 WritePartsComplete,
 								   const uint64_t													 TotalPartWriteCount,
-								   FilteredRate&													 FilteredWrittenBytesPerSecond);
+								   FilteredRate&													 FilteredWrittenBytesPerSecond,
+								   bool																 EnableBacklog);
 
 	void VerifyAndCompleteChunkSequencesAsync(std::span<const uint32_t> RemoteSequenceIndexes, ParallelWork& Work);
 	bool CompleteSequenceChunk(uint32_t RemoteSequenceIndex, std::span<std::atomic<uint32_t>> SequenceIndexChunksLeftToWriteCounters);