[PGNCCL] Deprecate suppport of onCompletionHook

kwen2501 · kwen2501 · commit 6fee2fa1c950 · 2024-12-09T10:10:43.000-08:00
[ghstack-poisoned]
diff --git a/torch/csrc/distributed/c10d/ProcessGroupNCCL.cpp b/torch/csrc/distributed/c10d/ProcessGroupNCCL.cpp
@@ -1209,6 +1209,12 @@ uint64_t ProcessGroupNCCL::getSequenceNumberForGroup() {
 
 void ProcessGroupNCCL::registerOnCompletionHook(
     std::function<void(std::shared_ptr<WorkInfo>)>&& hook) {
+  TORCH_WARN_ONCE(
+      "ProcessGroupNCCL OnCompletion hook will be deprecated in favor of Flight Recorder. "
+      "Please check out FlightRecorder.hpp for information that is recorded at work completion. "
+      "You can file an issue if you want additional information to be recorded. "
+      "You can also file an RFC if you want Flight Recorder to accept plugins that customize the recording.")
+
   TORCH_CHECK_WITH(
       DistBackendError,
       onCompletionHook_ == nullptr,
