[relay][refactor] Cache Op::Get in passes to reduce lookup overhead

include/tvm/relay/op.h

@@ -594,12 +594,11 @@ inline ValueType OpMap<ValueType>::get(const Expr& expr,
   return map_.get<ValueType>(expr, def_value);
 }
 
-
 /*!
- * \brief Check that an expression is a "primtive operator".
+ * \brief Check that an expression is a "primitive operator".
  *
  * Will return true if the expression is an operator which
- * matches the form of primtive operators registered directly
+ * matches the form of primitive operators registered directly
  * by the Relay codebase.
  *
  * That is the arguments are all type variables, and there is a single

src/relay/backend/compile_engine.cc

@@ -21,6 +21,8 @@
  * \file relay/backend/compile_engine.cc
  * \brief Internal compialtion engine.
  */
+#include "compile_engine.h"
+
 #include <tvm/schedule.h>
 #include <tvm/packed_func_ext.h>
 #include <tvm/operation.h>
@@ -29,6 +31,7 @@
 #include <tvm/relay/analysis.h>
 #include <tvm/relay/expr.h>
 #include <tvm/relay/expr_functor.h>
+#include <tvm/relay/op.h>
 #include <tvm/relay/op_attr_types.h>
 #include <topi/tags.h>
 #include <utility>
@@ -38,7 +41,6 @@
 #include <vector>
 #include <unordered_map>
 #include "../ir/type_functor.h"
-#include "compile_engine.h"
 
 namespace tvm {
 namespace relay {
@@ -102,7 +104,7 @@ class ScheduleGetter :
       public ExprFunctor<Array<Tensor>(const Expr&)> {
  public:
   explicit ScheduleGetter(Target target)
-      : target_(target) {}
+      : target_(target), device_copy_op_(Op::Get("device_copy")) {}
 
   std::pair<Schedule, CachedFunc> Create(const Function& prim_func) {
     static auto fschedule =
@@ -250,11 +252,9 @@ class ScheduleGetter :
     CHECK(call_node->op.as<OpNode>())
         << "Primitive function only allows call into primitive ops";
     Op op = Downcast<Op>(call_node->op);
-    // Check if the op is a device copy op.
-    bool is_copy_op = op.same_as(Op::Get("device_copy"));
     Array<Tensor> outputs;
     // Skip fcompute for device copy operators as it is not registered.
-    if (is_copy_op) {
+    if (op == device_copy_op_) {
       const auto* copy_input = inputs[0].operator->();
       outputs.push_back(TensorNode::make(copy_input->shape, copy_input->dtype,
                                          Operation(), 0));
@@ -282,7 +282,7 @@ class ScheduleGetter :
     }
     // Set the name to `__copy`. It will be detected in graph runtime to perform
     // data copy across devices.
-    if (is_copy_op) {
+    if (op == device_copy_op_) {
       readable_name_stream_.str(std::string());
       readable_name_stream_ << "__copy";
     } else {
@@ -332,6 +332,9 @@ class ScheduleGetter :
   std::ostringstream readable_name_stream_;
   std::unordered_map<Expr, Array<Tensor>, NodeHash, NodeEqual> memo_;
   Array<Operation> scalars_;
+  // Cache device copy op for equivalence checking to reduce registry lookup
+  // overhead for each invocation of call node when retrieving schedules.
+  const Op& device_copy_op_;
 };
 
 // Creates shape function from functor.

src/relay/backend/interpreter.cc

@@ -246,10 +246,12 @@ class Interpreter :
       public ExprFunctor<Value(const Expr& n)>,
              PatternFunctor<bool(const Pattern& p, const Value& v)> {
  public:
-  Interpreter(Module mod,
-              DLContext context,
-              Target target)
-      : mod_(mod), context_(context), target_(target) {
+  Interpreter(Module mod, DLContext context, Target target)
+      : mod_(mod),
+        context_(context),
+        target_(target),
+        debug_op_(Op::Get("debug")),
+        shape_of_op_(Op::Get("shape_of")) {
     engine_ = CompileEngine::Global();
   }
 
@@ -263,7 +265,7 @@ class Interpreter :
     stack_.current_frame().locals.Set(id, v);
   }
 
-  inline Value Lookup(const Var& local) {
+  Value Lookup(const Var& local) {
     return stack_.Lookup(local);
   }
 
@@ -307,7 +309,7 @@ class Interpreter :
     return TupleValueNode::make(values);
   }
 
-  inline Value MakeClosure(const Function& func, Var letrec_name = Var()) {
+  Value MakeClosure(const Function& func, Var letrec_name = Var()) {
     tvm::Map<Var, Value> captured_mod;
     Array<Var> free_vars = FreeVars(func);
 
@@ -454,9 +456,9 @@ class Interpreter :
 
   Value InvokePrimitiveOp(const Function& func,
                           const Array<Value>& args) {
-    auto call_node = func->body.as<CallNode>();
+    const auto* call_node = func->body.as<CallNode>();
 
-    if (call_node && call_node->op == Op::Get("debug")) {
+    if (call_node && call_node->op == debug_op_) {
       auto dattrs = call_node->attrs.as<DebugAttrs>();
       auto interp_state = this->get_state(call_node->args[0]);
 
@@ -540,7 +542,7 @@ class Interpreter :
     Array<Shape> out_shapes;
     auto ret_type = func->body->checked_type();
     bool is_dyn = IsDynamic(func->checked_type());
-    if (call_node->op == Op::Get("shape_of")) {
+    if (call_node->op == shape_of_op_) {
       // The output shape of shape_of must be static since Relay doesn't support
       // dynamic rank tensors.
       is_dyn = false;
@@ -782,6 +784,9 @@ class Interpreter :
   Stack stack_;
   // Backend compile engine.
   CompileEngine engine_;
+  // Cache ops that need to be frequently used later to reduce lookup overhead.
+  const Op& debug_op_;
+  const Op& shape_of_op_;
 };
 
 

src/relay/pass/canonicalize_cast.cc

@@ -62,6 +62,8 @@ namespace relay {
 // \endcode
 class CastCanonicalizer : public ExprMutator {
  public:
+  CastCanonicalizer() : cast_op_(Op::Get("cast")) {}
+
   Expr VisitExpr_(const CallNode* call) {
     static auto fpattern = Op::GetAttr<TOpPattern>("TOpPattern");
 
@@ -91,15 +93,17 @@ class CastCanonicalizer : public ExprMutator {
 
  private:
   std::unordered_map<const Node*, size_t> ref_counter_;
+  // cast op is frequently checked for equivalence. Therefore, we cache it to
+  // reduce lookup overhead.
+  const Op& cast_op_;
+
 
   Expr GetNewCallArg(const Expr& e) {
     // if e is a upcast and ref count > 1, create an copy; otherwise call the default visitor
-
-    static auto& cast = Op::Get("cast");
     Expr new_expr = this->VisitExpr(e);
 
     if (const CallNode* call = e.as<CallNode>()) {
-      if (call->op.same_as(cast)) {
+      if (call->op == cast_op_) {
         auto attrs = call->attrs.as<CastAttrs>();
         const auto* from_type = call->args[0]->type_as<TensorTypeNode>();
         CHECK(from_type);
@@ -108,7 +112,7 @@ class CastCanonicalizer : public ExprMutator {
           if (++ref_counter_[call] > 1) {
             const CallNode* new_call = new_expr.as<CallNode>();
             CHECK(new_call);
-            CHECK(new_call->op.same_as(cast));
+            CHECK(new_call->op == cast_op_);
             return CallNode::make(new_call->op, new_call->args, new_call->attrs,
                  new_call->type_args);
           }

src/relay/pass/canonicalize_ops.cc

@@ -24,6 +24,7 @@
  */
 #include <tvm/relay/analysis.h>
 #include <tvm/relay/expr_functor.h>
+#include <tvm/relay/op.h>
 #include <tvm/relay/attrs/nn.h>
 #include <tvm/relay/transform.h>
 #include "pattern_util.h"
@@ -33,10 +34,11 @@ namespace relay {
 
 class BiasAddSimplifier : public ExprMutator {
  public:
+  BiasAddSimplifier() : bias_add_op_(Op::Get("nn.bias_add")) {}
+
   Expr VisitExpr_(const CallNode* n) {
-    static const Op& bias_add = Op::Get("nn.bias_add");
     auto new_n = ExprMutator::VisitExpr_(n);
-    if (n->op.same_as(bias_add)) {
+    if (n->op == bias_add_op_) {
       Call call = Downcast<Call>(new_n);
       CHECK_EQ(call->args.size(), 2);
       const BiasAddAttrs* param = call->attrs.as<BiasAddAttrs>();
@@ -54,6 +56,10 @@ class BiasAddSimplifier : public ExprMutator {
     }
     return new_n;
   }
+
+ private:
+  // Cache the bias_add for equivalence checking.
+  const Op& bias_add_op_;
 };
 
 Expr CanonicalizeOps(const Expr& e) {

src/relay/pass/combine_parallel_op.cc

@@ -27,37 +27,38 @@
 #include <tvm/relay/expr_functor.h>
 #include <tvm/relay/attrs/nn.h>
 #include <tvm/relay/attrs/transform.h>
+#include <tvm/relay/op.h>
 #include <tvm/relay/op_attr_types.h>
 #include <tvm/relay/transform.h>
+#include <algorithm>
+#include <utility>
 #include <unordered_map>
 #include <unordered_set>
-#include "./expr_subst.h"
-#include "./pattern_util.h"
-#include "./combine_parallel_op.h"
+#include "expr_subst.h"
+#include "pattern_util.h"
+#include "combine_parallel_op.h"
 
 
 namespace tvm {
 namespace relay {
 
-BranchGroupFinder::BranchGroupFinder(const std::string& op_name,
+BranchGroupFinder::BranchGroupFinder(const Op& op,
                                      FIsSupportedOp fis_supported_op,
                                      FAreCompatibleOps fare_compatible_ops)
-  : op_name_(op_name),
+  : cached_op_(op),
     fis_supported_op_(fis_supported_op),
     fare_compatible_ops_(fare_compatible_ops) {
 }
 
 std::vector<Group> BranchGroupFinder::Find(const Expr& expr) {
-  const Op& op = Op::Get(op_name_);
-
   this->VisitExpr(expr);
 
   std::vector<Group> groups;
   for (const auto& root : op_roots_) {
     const auto& children = children_map_.at(root);
     size_t ngroups = groups.size();
     for (const CallNode* child : children) {
-      if (!child->op.same_as(op)) continue;
+      if (child->op != cached_op_) continue;
 
       auto&& branch = CreateBranch(child);
       // add the branch to a group, or create a new group
@@ -97,9 +98,8 @@ Branch BranchGroupFinder::CreateBranch(const CallNode* op) {
 }
 
 void BranchGroupFinder::VisitExpr_(const CallNode* n) {
-  const Op& op = Op::Get(op_name_);
   ExprVisitor::VisitExpr_(n);
-  if (n->op.same_as(op) && fis_supported_op_(n)) {
+  if (n->op == cached_op_ && fis_supported_op_(n)) {
     op_roots_.insert(n->args[0]);
     children_map_[n->args[0]].push_back(n);
   } else {
@@ -110,12 +110,12 @@ void BranchGroupFinder::VisitExpr_(const CallNode* n) {
 }
 
 ParallelOpCombiner::ParallelOpCombiner(const std::string& op_name, uint64_t min_num_branches)
-  : op_name_(op_name),
+  : cached_op_(Op::Get(op_name)),
     min_num_branches_(min_num_branches) {
 }
 
 Expr ParallelOpCombiner::Combine(const Expr& expr) {
-  auto groups = BranchGroupFinder(op_name_,
+  auto groups = BranchGroupFinder(cached_op_,
                                   [&](const CallNode* n) {
                                     return IsSupportedOp(n);
                                   },

src/relay/pass/combine_parallel_op.h

@@ -68,13 +68,13 @@ class BranchGroupFinder : private ExprVisitor {
  public:
   /*
    * \brief Constructor
-   * \param op_name name of op to start each group
+   * \param op The op that indicates the start of each group
    * \param fis_supported_op function that returns true if op
    *                         is supported for combining
    * \param fare_compatible_ops function that returns true if
    *                            two ops are compatible for combining
    */
-  BranchGroupFinder(const std::string& op_name,
+  BranchGroupFinder(const Op& op,
                     FIsSupportedOp fis_supported_op,
                     FAreCompatibleOps fare_compatible_ops);
 
@@ -87,8 +87,8 @@ class BranchGroupFinder : private ExprVisitor {
   std::vector<Group> Find(const Expr& expr);
 
  private:
-  /* \brief name of op to find parallel branches for */
-  std::string op_name_;
+  /* \brief Cache the op for finding parallel branches */
+  const Op& cached_op_;
 
   /* \brief function to return true if op is eligible to be combined,
    *         false otherwise 
@@ -205,8 +205,8 @@ class ParallelOpCombiner {
                                  ExprSubstMap* subst_map) = 0;
 
  private:
-  /* \brief name of op to be combined */
-  std::string op_name_;
+  /* \brief Cache the op to be combined */
+  const Op& cached_op_;
 
   /* \brief minimum number of parallel branches to combine */
   uint64_t min_num_branches_;