Add parameter to set number of bits in fractional

python/tvm/relay/backend/contrib/ethosu/util.py

@@ -270,6 +270,13 @@ def is_fixed_point_enabled() -> bool:
     return bool(compiler_attrs.enable_fixed_point)
 
 
+def get_fixed_point_fraction_size() -> int:
+    """Function to get the number of bits used to
+    represent the fractional part of a fixed point number"""
+    compiler_attrs = tvm.get_global_func("relay.ext.ethos-u.get_compiler_attrs")()
+    return int(compiler_attrs.fixed_point_fraction_size)
+
+
 def is_striping_enabled() -> bool:
     """Determine whether the cascader is enabled"""
     compiler_attrs = tvm.get_global_func("relay.ext.ethos-u.get_compiler_attrs")()

python/tvm/relay/op/contrib/ethosu.py

@@ -1811,10 +1811,12 @@ def __init__(self, func_body):
         from tvm.relay.backend.contrib.ethosu.util import QDenseArgs  # type: ignore
         from tvm.relay.backend.contrib.ethosu.util import BiasAddArgs, RequantArgs
 
-        fract_scale = tvm.relay.Constant(tvm.nd.array(np.array(1 / 2**15)))
-        fract_zero_point = tvm.relay.Constant(tvm.nd.array(np.array(0, dtype="int32")))
         self.activation = None
         if util.is_fixed_point_enabled():
+            fract_scale = tvm.relay.Constant(
+                tvm.nd.array(np.array(1 / 2 ** util.get_fixed_point_fraction_size()))
+            )
+            fract_zero_point = tvm.relay.Constant(tvm.nd.array(np.array(0, dtype="int32")))
             qnn_dense = func_body
             bias_add = None
         else:

src/relay/backend/contrib/ethosu/compiler_attrs.cc

@@ -43,6 +43,7 @@ struct EthosUCompilerConfigNode : public tvm::AttrsNode<EthosUCompilerConfigNode
   Bool enable_striping = Bool(false);
   Bool disable_copying_constants = Bool(false);
   Bool enable_fixed_point = Bool(false);
+  Integer fixed_point_fraction_size = Integer(0);
   String dev_force_block_config;
   String dev_max_open_plans;
   String dev_max_closed_plans;
@@ -80,6 +81,11 @@ struct EthosUCompilerConfigNode : public tvm::AttrsNode<EthosUCompilerConfigNode
             "enabled, it is assumed that input data should be converted to fixed point "
             "representation")
         .set_default(Bool(false));
+    TVM_ATTR_FIELD(fixed_point_fraction_size)
+        .describe(
+            "Fraction size refers to the number of bits used to represent the fractional part of a "
+            "fixed point number")
+        .set_default(Integer(0));
     TVM_ATTR_FIELD(dev_force_block_config)
         .describe((dev_warning + String("Force the block config to a given value; format = "
                                         "\"[BLK_HEIGHT]x[BLK_WIDTH]x[BLK_DEPTH]\""))

tests/python/contrib/test_ethosu/infra.py

@@ -125,6 +125,7 @@ def create_test_runner(
     enable_striping=False,
     workspace_pools=None,
     enable_fixed_point=False,
+    fixed_point_fraction_size=0,
 ):
 
     file_dir = os.path.dirname(os.path.abspath(__file__))
@@ -170,6 +171,7 @@ def create_test_runner(
                 "enable_cascader": enable_cascader,
                 "enable_striping": enable_striping,
                 "enable_fixed_point": enable_fixed_point,
+                "fixed_point_fraction_size": fixed_point_fraction_size,
             },
             "tir.usmp.enable": enable_usmp,
             "tir.usmp.algorithm": "hill_climb",
@@ -336,6 +338,7 @@ def compare_ethosu_with_reference(
     print_cmm=False,
     enable_cascader=None,
     enable_fixed_point=False,
+    fixed_point_fraction_size=0,
 ):
     if enable_cascader is None:
         enable_cascader = "u65" not in accel_type
@@ -363,6 +366,7 @@ def compare_ethosu_with_reference(
         enable_striping=False,
         workspace_pools=workspace_pools,
         enable_fixed_point=enable_fixed_point,
+        fixed_point_fraction_size=fixed_point_fraction_size,
     )
     compiled_models = build_source(
         mod,

tests/python/contrib/test_ethosu/test_codegen.py

@@ -1627,7 +1627,7 @@ def subtract_sigmoid_function(lhs, rhs):
 @pytest.mark.parametrize("accel_type", ["ethos-u55-256", "ethos-u65-256"])
 @pytest.mark.parametrize(
     "ifm_shape,ofm_channels,fract_size,tolerance",
-    [[(1, 16), 8, 15, 0.001], [(2, 8), 16, 14, 0.3]],
+    [[(1, 16), 8, 15, 0.001], [(2, 8), 16, 14, 0.001], [(4, 8), 16, 12, 0.001]],
 )
 def test_ethosu_matmul_fixed_point(accel_type, ifm_shape, ofm_channels, fract_size, tolerance):
     np.random.seed(0)
@@ -1661,7 +1661,7 @@ def convert_to_fixed_point(arr, fract_size):
     output_data = {"output": convert_to_fixed_point(output_data, fract_size)}
     tolerance = convert_to_fixed_point(tolerance, fract_size)
 
-    config = {"enable_fixed_point": True}
+    config = {"enable_fixed_point": True, "fixed_point_fraction_size": fract_size}
     with tvm.transform.PassContext(config={"relay.ext.ethos-u.options": config}):
         ethosu_mod = partition_for_ethosu(cpu_mod)
 
@@ -1673,6 +1673,7 @@ def convert_to_fixed_point(arr, fract_size):
         enable_cascader=False,
         output_tolerance=tolerance,
         enable_fixed_point=True,
+        fixed_point_fraction_size=fract_size,
     )