From 92e27c5e893eef975060cc96f045231e4339a5e2 Mon Sep 17 00:00:00 2001
From: Bram Wasti <bwasti@fb.com>
Date: Tue, 26 Nov 2019 14:29:26 -0800
Subject: [PATCH] Flag to disable Variable

Summary:
using `buck build mode/opt mode/no-gpu //experimental/ngimel/benchmark_framework_overheads:cpp_benchmark`

```
devvm497.prn3.facebook.com:/data/users/bwasti/fbsource/fbcode $ ./cpp_benchmark --niter 10000
creating inputs, number of dimensions 1
starting op
benchmarking 10000 iterations
using cpp frontend
elapsed time per iteration 0.90638 us
```

```
devvm497.prn3.facebook.com:/data/users/bwasti/fbsource/fbcode $ ./cpp_benchmark --niter 10000 --disable_variable_dispatch
creating inputs, number of dimensions 1
starting op
benchmarking 10000 iterations
using cpp frontend
elapsed time per iteration 0.775436 us
```

Test Plan: let all tests run

Reviewed By: smessmer

Differential Revision: D18654276

fbshipit-source-id: 362812b2c87ec428448b2ac65baac45f492fdce4
---
 aten/src/ATen/native/TensorProperties.cpp | 4 ++--
 c10/core/impl/LocalTensorTypeSet.cpp      | 8 ++++++++
 c10/core/impl/LocalTensorTypeSet.h        | 3 +++
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/aten/src/ATen/native/TensorProperties.cpp b/aten/src/ATen/native/TensorProperties.cpp
index 65a79865a65..050442aea89 100644
--- a/aten/src/ATen/native/TensorProperties.cpp
+++ b/aten/src/ATen/native/TensorProperties.cpp
@@ -57,7 +57,7 @@ bool cudnn_is_acceptable(const Tensor& self) {
 Tensor detach(const Tensor& self) {
 #ifndef USE_STATIC_DISPATCH
   // this just exists to give us a hook in VariableType and an entry in Declarations.yaml
-  AT_ERROR("detach is not implemented for Tensor");
+  //AT_ERROR("detach is not implemented for Tensor");
 #endif
   // this is no-op for USE_STATIC_DISPATCH mode
   return self;
@@ -66,7 +66,7 @@ Tensor detach(const Tensor& self) {
 Tensor & detach_(Tensor & self) {
 #ifndef USE_STATIC_DISPATCH
   // this just exists to give us a hook in VariableType and an entry in Declarations.yaml
-  AT_ERROR("detach_ is not implemented for Tensor");
+  //AT_ERROR("detach_ is not implemented for Tensor");
 #endif
   // this is no-op for USE_STATIC_DISPATCH mode
   return self;
diff --git a/c10/core/impl/LocalTensorTypeSet.cpp b/c10/core/impl/LocalTensorTypeSet.cpp
index f5c328c98d1..e144cace040 100644
--- a/c10/core/impl/LocalTensorTypeSet.cpp
+++ b/c10/core/impl/LocalTensorTypeSet.cpp
@@ -5,6 +5,8 @@
 namespace c10 {
 namespace impl {
 
+C10_DEFINE_bool(disable_variable_dispatch, false, "This flag forcibly disables the Variable code paths from executing, which currently breaks profiling in the process.");
+
 namespace {
 
 /// In the CAFFE2_FB_LIMITED_MOBILE_CAPABILITY build setting,
@@ -23,6 +25,12 @@ static PODLocalTensorTypeSet raw_local_tensor_type_set;
 } // anonymous namespace
 
 LocalTensorTypeSet tls_local_tensor_type_set() {
+  // Hack until variable performance is fixed
+  if (FLAGS_disable_variable_dispatch) {
+    raw_local_tensor_type_set.set_excluded(
+      raw_local_tensor_type_set.excluded().add(
+        TensorTypeId::VariableTensorId));
+  }
   return raw_local_tensor_type_set;
 }
 
diff --git a/c10/core/impl/LocalTensorTypeSet.h b/c10/core/impl/LocalTensorTypeSet.h
index 728cc8afe3f..2cf5d3993d9 100644
--- a/c10/core/impl/LocalTensorTypeSet.h
+++ b/c10/core/impl/LocalTensorTypeSet.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <c10/core/TensorTypeSet.h>
+#include <c10/util/Flags.h>
 
 // TLS management for TensorTypeSet (the "local" TensorTypeSet(s))
 //
@@ -22,6 +23,8 @@
 namespace c10 {
 namespace impl {
 
+C10_DECLARE_bool(disable_variable_dispatch);
+
 // POD version of LocalTensorTypeSet.  Declared here just so that
 // we can put it in the guards.
 struct C10_API PODLocalTensorTypeSet {