add per_channel_minmax (#1990)

Signed-off-by: yiliu30 <[email protected]>

Author: yiliu30

neural_compressor/torch/algorithms/pt2e_quant/utility.py

@@ -17,7 +17,12 @@
 
 import torch
 import torch.ao.quantization.quantizer.x86_inductor_quantizer as xiq
-from torch.ao.quantization.observer import HistogramObserver, MinMaxObserver, PlaceholderObserver
+from torch.ao.quantization.observer import (
+    HistogramObserver,
+    MinMaxObserver,
+    PerChannelMinMaxObserver,
+    PlaceholderObserver,
+)
 from torch.ao.quantization.quantizer import QuantizationSpec
 from torch.ao.quantization.quantizer.x86_inductor_quantizer import QuantizationConfig, X86InductorQuantizer
 
@@ -48,19 +53,23 @@ def create_quant_spec_from_config(dtype, sym, granularity, algo, is_dynamic=Fals
         "placeholder": PlaceholderObserver,
         "minmax": MinMaxObserver,
         "kl": HistogramObserver,
+        "per_channel_minmax": PerChannelMinMaxObserver,
     }
     # Force to use placeholder observer for dynamic quantization
     if is_dynamic:
         algo = "placeholder"
-    # algo
-    observer_or_fake_quant_ctr = observer_mapping[algo]
+    if f"{granularity}_{algo}" in observer_mapping:
+        observer_or_fake_quant_ctr = observer_mapping[f"{granularity}_{algo}"]
+    else:
+        observer_or_fake_quant_ctr = observer_mapping[algo]
     # qscheme
     qscheme = qscheme_mapping[granularity][sym]
     quantization_spec = QuantizationSpec(
         dtype=select_dtype,
         quant_min=min_max_mapping[select_dtype][0],
         quant_max=min_max_mapping[select_dtype][1],
         observer_or_fake_quant_ctr=observer_or_fake_quant_ctr,
+        ch_axis=0,
         qscheme=qscheme,
         is_dynamic=is_dynamic,
     )

test/3x/torch/quantization/test_pt2e_quant.py

@@ -98,7 +98,10 @@ def forward(self, x: torch.Tensor) -> torch.Tensor:
         return exported_model, example_inputs
 
     @pytest.mark.skipif(get_torch_version() <= TORCH_VERSION_2_2_2, reason="Requires torch>=2.3.0")
-    def test_quantize_simple_model(self, force_not_import_ipex):
+    @pytest.mark.parametrize("granularity", ["per_tensor", "per_channel"])
+    def test_quantize_simple_model(self, granularity, force_not_import_ipex):
+        from neural_compressor.torch.quantization import StaticQuantConfig
+
         model, example_inputs = self.build_simple_torch_model_and_example_inputs()
         float_model_output = model(*example_inputs)
         quant_config = None
@@ -107,7 +110,7 @@ def calib_fn(model):
             for i in range(4):
                 model(*example_inputs)
 
-        quant_config = get_default_static_config()
+        quant_config = StaticQuantConfig(w_granularity=granularity)
         q_model = quantize(model=model, quant_config=quant_config, run_fn=calib_fn)
         from torch._inductor import config