Revert "Update the heuristic for AArch64 bmm/baddbmm (#149122)"

This reverts commit d759a517af.

Reverted https://github.com/pytorch/pytorch/pull/149122 on behalf of https://github.com/jeanschmidt due to breaking internal models, @malfet may you help merge this? ([comment](https://github.com/pytorch/pytorch/pull/149122#issuecomment-2904703075))

aten/src/ATen/native/LinearAlgebra.cpp

@@ -1360,6 +1360,41 @@ Tensor outer(const Tensor& self, const Tensor& vec2) {
 #endif
 
 
+static inline int64_t get_mkldnn_matmul_min_dim() {
+  static auto value = [&] {
+    const int64_t default_min_dim = [&] {
+      // Minimum dimension requirement for MKLDNN; derived based on experiments.
+      //it's enabled on all Neoverse cpus.
+      return is_arm_neoverse() ? 8 : 0;
+    }();
+    const auto value = c10::utils::get_env("TORCH_MKLDNN_MATMUL_MIN_DIM");
+    return value.has_value() ? std::stoi(value.value()) : default_min_dim;
+  }();
+  return value;
+}
+
+
+static inline int64_t get_mkldnn_matmul_min_size() {
+  static auto value = [&] {
+    const int64_t default_min_size = [&] {
+      // Minimum size requirement for MKLDNN; derived based on experiments.
+      // it's enabled on all Neoverse cpus.
+      return is_arm_neoverse() ? 8 * 1024 : 0;
+    }();
+    const auto value = c10::utils::get_env("TORCH_MKLDNN_MATMUL_MIN_SIZE");
+    return value.has_value() ? std::stoi(value.value()) : default_min_size;
+  }();
+  return value;
+}
+
+
+static inline bool apply_mkldnn_matmul_heur(int64_t m, int64_t k, int64_t n) {
+  const int64_t min_dim = get_mkldnn_matmul_min_dim();
+  const int64_t min_size = get_mkldnn_matmul_min_size();
+  return at::globalContext().userEnabledMkldnn() && m > min_dim && k > min_dim && n > min_dim && m * k * n > min_size;
+}
+
+
 static void addmm_impl_cpu_(
     Tensor &result, const Tensor &self, Tensor m1, Tensor m2, const Scalar& beta, const Scalar& alpha) {
   TORCH_INTERNAL_ASSERT(self.dim() == 2 && m1.dim() == 2 && m2.dim() == 2);
@@ -1479,7 +1514,8 @@ static void addmm_impl_cpu_(
   // that will call then into Arm® Compute Library (ACL) GEMM kernel and also
   // additionally have support for running kernel with BF16 instructions
   if (transpose_c) {
-    if (use_mkldnn_matmul(b, a, c) && transpose_a && !transpose_b && result.scalar_type() == at::ScalarType::Float) {
+    bool apply_heur = apply_mkldnn_matmul_heur(b.sizes()[0], b.sizes()[1], a.sizes()[1]);
+    if (apply_heur && transpose_a && !transpose_b && result.scalar_type() == at::ScalarType::Float) {
       try {
         mkldnn_matmul(b, a, c, beta.to<float>(), alpha.to<float>());
         // We have dispatched to ACL GEMM for single precision float
@@ -1735,7 +1771,8 @@ static inline void bmm_out_or_baddbmm_(const Tensor& self_or_result_, const Tens
         (strides[1] == 1 && (sizes[2] == 1 || strides[2] >= sizes[1]));
   };
 
-  if (use_mkldnn_matmul(batch1, batch2, self_or_result)) {
+  bool apply_heur = apply_mkldnn_matmul_heur(batch1.sizes()[1], batch1.sizes()[2], batch2.sizes()[2]);
+  if (apply_heur && use_mkldnn_matmul(batch1, batch2, self_or_result)) {
     try {
       mkldnn_matmul(batch1, batch2, self_or_result, beta.to<float>(), alpha.to<float>());
       return;

aten/src/ATen/native/mkldnn/Matmul.cpp

@@ -391,42 +391,6 @@ void mkldnn_matmul(
 
 }
 
-#if AT_MKLDNN_ACL_ENABLED()
-// Experimentally derived heuristics for MKLDNN+ACL on NEOVERSE cores
-static inline int64_t get_mkldnn_acl_addmm_min_dim() {
-  static auto value = [&] {
-    const int64_t default_min_dim = [&] {
-      return is_arm_neoverse() ? 8 : 0;
-    }();
-    const char* ptr = std::getenv("TORCH_MKLDNN_ADDMM_MIN_DIM");
-    return ptr != nullptr ? std::atoi(ptr) : default_min_dim;
-  }();
-  return value;
-}
-
-static inline int64_t get_mkldnn_acl_addmm_min_size() {
-  static auto value = [&] {
-    const int64_t default_min_size = [&] {
-      return is_arm_neoverse() ? 8 * 1024 : 0;
-    }();
-    const char* ptr = std::getenv("TORCH_MKLDNN_ADDMM_MIN_SIZE");
-    return ptr != nullptr ? std::atoi(ptr) : default_min_size;
-  }();
-  return value;
-}
-
-static inline int64_t get_mkldnn_acl_bmm_baddbmm_threshold() {
-  static auto value = [&] {
-    const int64_t default_threshold = [&] {
-      return is_arm_neoverse() ? 1L << 22 : 0;
-    }();
-    const char* ptr = std::getenv("TORCH_MKLDNN_BMM_BADDBMM_THRESHOLD");
-    return ptr != nullptr ? std::atoi(ptr) : default_threshold;
-  }();
-  return value;
-}
-#endif
-
 static inline bool checksize(const Tensor& mat1, const Tensor& mat2){
   // if dim = 2, mat1's size = (m * n), mat2's size = (n * k)
   // else if dim = 3, mat1's size = (b * m * n), mat2's size = (b * n * k)
@@ -441,26 +405,10 @@ static inline bool checksize(const Tensor& mat1, const Tensor& mat2){
     return mat1.size(0) * mat1.size(1) > mkldnn_gemm_min_size;
   } else if (mat2.dim() == 2 && mat2.dim() == 2) {
     // aten::addmm
-#if AT_MKLDNN_ACL_ENABLED()
-    const int64_t mkldnn_acl_addmm_min_dim = get_mkldnn_acl_addmm_min_dim();
-    const int64_t mkldnn_acl_addmm_min_size = get_mkldnn_acl_addmm_min_size();
-    // M > MIN_DIM and N > MIN_DIM and K > MIN_DIM and M*N*K > MIN_SIZE
-    return mat1.size(0) > mkldnn_acl_addmm_min_dim
-        && mat1.size(1) > mkldnn_acl_addmm_min_dim
-        && mat2.size(1) > mkldnn_acl_addmm_min_dim
-        && mat1.size(0) * mat1.size(1) * mat2.size(1) > mkldnn_acl_addmm_min_size;
-#else
     return mat1.size(0) * mat1.size(1) * mat2.size(1) > mkldnn_gemm_min_size;
-#endif
   } else {
     // aten::bmm, aten::baddbmm
-#if AT_MKLDNN_ACL_ENABLED()
-    const int64_t mkldnn_acl_bmm_baddbmm_threshold = get_mkldnn_acl_bmm_baddbmm_threshold();
-    // BATCH_SIZE^2 * M * N * K >= THRESHOLD
-    return mat1.size(0) * mat1.size(0) * mat1.size(1) * mat1.size(2) * mat2.size(2) >= mkldnn_acl_bmm_baddbmm_threshold;
-#else
     return mat1.size(0) * mat1.size(1) * mat1.size(2) * mat2.size(2) > mkldnn_gemm_min_size;
-#endif
   }
 }