add SmUtilization check for Reduce Region

paddle/cinn/ir/group_schedule/config/group_tile_config.cc

@@ -211,9 +211,16 @@ TileConfigMap BuildVectorizeConfig(
   };
 
   bool is_sm_fully_utilized = true;
-  auto CheckSmUtilization = [sm_count, max_threads_per_sm, max_blocks_per_sm](
-                                int total_threads, int block_size) -> bool {
-    int blocks_needed = CeilDiv(total_threads, block_size);
+  // Only proceed with vectorization if SM utilization exceeds 100%
+  auto CheckSmUtilization =
+      [&](int input_size, int block_size, std::string last_dim) -> bool {
+    if (last_dim != "S" && last_dim != "R") {
+      VLOG(5) << "Invalid last_dim in SmUtilization Check: " << last_dim;
+      return false;
+    }
+
+    int blocks_needed =
+        (last_dim == "S") ? CeilDiv(input_size, block_size) : input_size;
     int sms_needed = CeilDiv(blocks_needed, max_blocks_per_sm);
     float sm_utilization = static_cast<float>(sms_needed) / sm_count;
 
@@ -239,6 +246,8 @@ TileConfigMap BuildVectorizeConfig(
       if (warp_nums > 1 || spatial_numel < warp_nums * 64) {
         rd_thread_num = warp_nums * kWarpSize;
         if (CheckVectorize(reduce_numel, rd_thread_num, vectorize_factor)) {
+          is_sm_fully_utilized =
+              CheckSmUtilization(spatial_numel, rd_thread_num, "R");
           break;
         }
         reduce_method = BlockReduceMethod();
@@ -257,7 +266,8 @@ TileConfigMap BuildVectorizeConfig(
       // warp_nums = Trim(warp_nums, 1, 32);
       sp_thread_num = kWarpSize * warp_nums;
       if (CheckVectorize(spatial_numel, sp_thread_num, vectorize_factor)) {
-        is_sm_fully_utilized = CheckSmUtilization(spatial_numel, sp_thread_num);
+        is_sm_fully_utilized = CheckSmUtilization(
+            spatial_numel / vectorize_factor, sp_thread_num, "S");
         break;
       }
     }