graph: interface: fix memory size for u4/s4

Author: TaoLv

src/graph/interface/logical_tensor.cpp

@@ -1,5 +1,5 @@
 /*******************************************************************************
-* Copyright 2020-2023 Intel Corporation
+* Copyright 2020-2024 Intel Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -38,7 +38,9 @@ size_t logical_tensor_wrapper_t::size() const {
                     static_cast<size_t>(strided_pdim * effective_stride));
         }
 
-        return max_size * data_type_size();
+        size_t data_size = utils::div_up(
+                max_size * data_type_size(), sub_byte_data_type_multiplier());
+        return data_size;
     } else if (is_opaque()) {
         size_t layout_id = lt->layout.layout_id;
         auto backend

src/graph/interface/logical_tensor.hpp

@@ -1,5 +1,5 @@
 /*******************************************************************************
-* Copyright 2020-2023 Intel Corporation
+* Copyright 2020-2024 Intel Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -154,6 +154,13 @@ struct logical_tensor_wrapper_t {
                 /* check_dtype = */ true);
     }
 
+    /** For sub-byte data types returns number of elements per byte.
+     * For the rest data types returns 1. */
+    size_t sub_byte_data_type_multiplier() const {
+        if (utils::one_of(data_type(), data_type::s4, data_type::u4)) return 2;
+        return 1;
+    }
+
     // return the size of data type
     size_t data_type_size() const { return types::data_type_size(data_type()); }
 

tests/gtests/graph/api/test_cpp_api_logical_tensor.cpp

@@ -311,4 +311,10 @@ TEST(APILogicalTensor, LogicalTensorSize) {
     ASSERT_EQ(lt_3.get_id(), id);
     ASSERT_EQ(lt_3.get_data_type(), data_type::s8);
     ASSERT_EQ(lt_3.get_mem_size(), num_elem * sizeof(int8_t));
+
+    logical_tensor lt_4 {id, data_type::s4, shape, layout_type::strided};
+    ASSERT_EQ(lt_4.get_id(), id);
+    ASSERT_EQ(lt_4.get_data_type(), data_type::s4);
+    // in case num_elem is not even.
+    ASSERT_EQ(lt_4.get_mem_size(), (num_elem + 1) / 2);
 }