SVE Implementation for SDDMMCOO with copyrhs op

SVE intrinsic code is added to improve the performance of SDDMMCOO Op
when bacst is disabled and reduce_size=1

Author: akote123

CMakeLists.txt

@@ -122,6 +122,17 @@ if (${BUILD_TYPE} STREQUAL "dev")
   if (MSVC)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /Od")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Od")
+  elseif ( CMAKE_SYSTEM_PROCESSOR MATCHES "(aarch64)|(AARCH64)")
+    # Check if the compiler supports ARMv8.2-A or later with SVE
+    include(CheckCCompilerFlag)
+    # Try to detect whether the system supports SVE
+    check_c_compiler_flag("-march=armv8.2-a+sve" SUPPORTS_SVE) 
+    # Output the result
+    if(SUPPORTS_SVE)
+      message(STATUS "Hardware supports SVE")
+      set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O0 -g3 -ggdb -march=armv8.2-a+sve")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O0 -g3 -ggdb -march=armv8.2-a+sve")
+    endif()
   else()
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O0 -g3 -ggdb")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O0 -g3 -ggdb")

src/array/cpu/sddmm.h

@@ -10,6 +10,10 @@
 #include <dgl/bcast.h>
 #include <dgl/runtime/parallel_for.h>
 
+#ifdef __ARM_FEATURE_SVE
+#include <arm_sve.h>  // to leverage sve intrinsics
+#endif
+
 #include "../selector.h"
 
 namespace dgl {
@@ -222,6 +226,54 @@ struct Dot {
 
 }  // namespace op
 
+// SDDMMCoo Specialization
+#ifdef __ARM_FEATURE_SVE
+template <>
+void SDDMMCoo <int32_t, float, dgl::aten::cpu::op::CopyRhs<float>, 0, 2> (
+    const BcastOff& bcast, const COOMatrix& coo, NDArray lhs, NDArray rhs, NDArray out) {
+  const bool has_idx = !IsNullArray(coo.data);
+  const int32_t* row = coo.row.Ptr<int32_t>();
+  const int32_t* col = coo.col.Ptr<int32_t>();
+  const int32_t* edges = coo.data.Ptr<int32_t>();
+  const float* X = lhs.Ptr<float>();
+  const float* Y = rhs.Ptr<float>();
+  const int64_t dim = bcast.out_len, lhs_dim = bcast.lhs_len,
+                rhs_dim = bcast.rhs_len, reduce_size = bcast.reduce_size;
+  float* O = out.Ptr<float>();
+#pragma omp parallel for
+  for (int64_t i = 0; i < coo.row->shape[0]; ++i) {
+      const int32_t rid = row[i];
+      const int32_t cid = col[i];
+      const int32_t eid = has_idx ? edges[i] : i;
+      float* out_off = O + eid * dim;
+      if (!bcast.use_bcast && reduce_size == 1) {
+          for (int64_t k = 0; k < dim; k += svcntw()) {
+              svbool_t pgk = svwhilelt_b32(k, dim);
+              int64_t rhs_base1 = cid * rhs_dim; 
+              svfloat32_t rhs_off_vector = svld1_f32(pgk, &Y[rhs_base1 + k]);
+              svst1_f32(pgk, &out_off[k], rhs_off_vector);
+          }
+      } else {
+          //with bcast.use_bcast == true, Op::use_lhs == false, and Op::Call
+          for (int64_t k = 0; k < dim; ++k) {
+              const int64_t lhs_add = bcast.use_bcast ? bcast.lhs_offset[k] : k;
+              const int64_t rhs_add = bcast.use_bcast ? bcast.rhs_offset[k] : k;
+              const float* lhs_off =
+              dgl::aten::cpu::op::CopyRhs<float>::use_lhs ? X + rid * lhs_dim +
+                            lhs_add * reduce_size
+                      : nullptr;
+      
+              const float* rhs_off =
+                dgl::aten::cpu::op::CopyRhs<float>::use_rhs ? Y +  cid * rhs_dim +
+                            rhs_add * reduce_size
+                      : nullptr;
+              out_off[k] = dgl::aten::cpu::op::CopyRhs<float>::Call(lhs_off, rhs_off, bcast.reduce_size);
+          }
+      }
+  }
+}
+#endif
+
 }  // namespace cpu
 }  // namespace aten
 }  // namespace dgl