Minor cleanup in pointwise scheduler (#1858)

Author: zasdfgbnm

torch/csrc/jit/codegen/cuda/scheduler/pointwise.cpp

@@ -27,6 +27,18 @@ namespace {
 // Unused at the moment, commenting for clang tidy
 constexpr int64_t kThreadX = 128;
 
+// Returns number of non-reduction/non-broadcast dims in rfactor domain
+size_t nRootDims(const TensorView* tv) {
+  auto root_dom = tv->getMaybeRFactorDomain();
+  size_t tv_n_dims = 0;
+  for (auto dim : root_dom) {
+    if (!dim->isReduction() && !dim->isBroadcast()) {
+      tv_n_dims++;
+    }
+  }
+  return tv_n_dims;
+}
+
 // DomainMap uses the ComputeAtMap to find a reference TensorView
 // that maps to all iterDomains in the fusion.
 class DomainMap {
@@ -38,15 +50,21 @@ class DomainMap {
   // The pointwise scheduler heuristics requires a minimum number of axes.
   // The output reference tensor should respect this requirement.
   TensorView* findReferenceTensorView(int minimum_num_axes = 0) const {
+    TensorView* result = nullptr;
+    int max_dims = -1;
     for (auto output_tv :
          ir_utils::filterByType<TensorView>(fusion_->outputs())) {
       if (isValidReference(output_tv) &&
           hasMinimumSize(output_tv, minimum_num_axes) &&
           !output_tv->isFusionInput()) {
-        return output_tv;
+        int n_dims = nRootDims(output_tv);
+        if (n_dims > max_dims) {
+          result = output_tv;
+          max_dims = n_dims;
+        }
       }
     }
-    return nullptr;
+    return result;
   }
 
   static bool hasReferenceTensorView(Fusion* fusion) {
@@ -187,35 +205,11 @@ c10::optional<PointwiseParams> getPointwiseHeuristics(
   // Incase any buffer is of type DataType::Index
   DataType index_type = indexModeToDtype(runtime_info.getIndexMode());
 
-  TensorView* largest_out = nullptr;
-  int max_dims = -1;
-
   auto in_tvs = ir_utils::filterByType<TensorView>(fusion->inputs());
-  // Will want to access this with direct indexing later, convert now.
-  std::vector<TensorView*> out_tvs;
-  // Only use valid reference tensors during heuristics analysis
+
   DomainMap domain_map(fusion);
-  for (auto out_tv : ir_utils::filterByType<TensorView>(fusion->outputs())) {
-    if (domain_map.isValidReference(out_tv)) {
-      out_tvs.push_back(out_tv);
-    }
-  }
-  TORCH_INTERNAL_ASSERT(
-      !out_tvs.empty(), "No valid reference outputs were found!");
 
-  for (auto out_tv : out_tvs) {
-    int n_dims = 0;
-    for (auto id : out_tv->getMaybeRFactorDomain()) {
-      if (id->isReduction() || id->isBroadcast()) {
-        continue;
-      }
-      n_dims++;
-    }
-    if (n_dims > max_dims) {
-      largest_out = out_tv;
-      max_dims = n_dims;
-    }
-  }
+  TensorView* largest_out = domain_map.findReferenceTensorView();
 
   TORCH_INTERNAL_ASSERT(largest_out != nullptr);
 
@@ -224,15 +218,12 @@ c10::optional<PointwiseParams> getPointwiseHeuristics(
 
   // TODO: Set to 1?
   int64_t max_input_dtype_size = 2;
-  size_t n_tensors = 0;
 
   for (auto inp : in_tvs) {
     max_input_dtype_size = std::max(
         max_input_dtype_size,
         (int64_t)dataTypeSize(inp->getDataType().value(), index_type));
-    n_tensors++;
   }
-  n_tensors += std::distance(out_tvs.begin(), out_tvs.end());
 
   auto ref_root = largest_out->getMaybeRFactorDomain();
   std::vector<int64_t> elem_counts(ref_root.size(), 1);
@@ -533,7 +524,6 @@ c10::optional<PointwiseParams> getPointwiseHeuristics(
     std::cerr << "\n===== Pointwise Stats ========\n"
               << "num_elems: " << n_elems << "\n"
               << "elem_counts: " << elem_counts << "\n"
-              << "n_tensor_inputs: " << n_tensors << "\n"
               << "max_input_dtype_size: " << max_input_dtype_size << "\n"
               << "vectorize_factor: " << vectorize_factor << std::endl;
     std::cerr << "broadcast_byte_multiples: ";
@@ -563,20 +553,6 @@ LaunchParams schedulePointwise(
   return params.value().lparams;
 }
 
-namespace {
-// Returns number of non-reduction/non-broadcast dims in rfactor domain
-size_t nRootDims(const TensorView* tv) {
-  auto root_dom = tv->getMaybeRFactorDomain();
-  size_t tv_n_dims = 0;
-  for (auto dim : root_dom) {
-    if (!dim->isReduction() && !dim->isBroadcast()) {
-      tv_n_dims++;
-    }
-  }
-  return tv_n_dims;
-}
-} // namespace
-
 bool hasReferenceTensorView(Fusion* fusion) {
   return DomainMap::hasReferenceTensorView(fusion);
 }