message: Temporarily revert to using non-NCCL broadcast and all-gather.
diff: @@ -59,13 +59,13 @@ namespace {
  const char* GetCollectiveName(const CollectiveParams* cp, bool nccl) {
  switch (cp->instance.type) {
  case BROADCAST_COLLECTIVE:
  - return nccl ? "NcclBroadcast" : "HierarchicalTreeBroadcast";
  + return "HierarchicalTreeBroadcast";
  case REDUCTION_COLLECTIVE:
  return nccl ? "NcclReduce" : "RingReduce";
  case GATHER_COLLECTIVE:
  - return nccl ? "NcclGather" : "RingGather";
  + return "RingGather";
  default:
  return "undef";
  @@ -91,8 +91,13 @@ void CollectiveParamResolverLocal::CompleteGroupLocal(
  // Initialize group runtime details.
  CollectiveImplementationInterface* col_impl;
  +#if defined(GOOGLE_CUDA)
  + status = CollectiveRegistry::LookupParamResolverInstance("NcclReduce",
  + &col_impl);
  +#else
  status = CollectiveRegistry::LookupParamResolverInstance(
  GetCollectiveName(cp, nccl_), &col_impl);
  +#endif
  if (status.ok()) {
  status = col_impl->InitializeCollectiveGroupRuntimeDetails(
  &gr->group.runtime_details);
  