[quantization] fix channelwise conversion with scalar weight scale (#4596)

test/srt/test_eval_fp8_accuracy.py

@@ -6,6 +6,8 @@ from sglang.test.run_eval import run_eval
 from sglang.test.test_utils import (
     DEFAULT_FP8_MODEL_NAME_FOR_ACCURACY_TEST,
     DEFAULT_FP8_MODEL_NAME_FOR_DYNAMIC_QUANT_ACCURACY_TEST,
+    DEFAULT_FP8_MODEL_NAME_FOR_MODELOPT_QUANT_ACCURACY_TEST,
+    DEFAULT_FP8_MODEL_NAME_FOR_MODELOPT_QUANT_ACCURACY_TEST_REVISION,
     DEFAULT_MODEL_NAME_FOR_TEST,
     DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
     DEFAULT_URL_FOR_TEST,
@@ -105,5 +107,47 @@ class TestEvalFP8DynamicQuantAccuracy(unittest.TestCase):
         )
 
 
+class TestEvalFP8ModelOptQuantAccuracy(unittest.TestCase):
+
+    def _run_test(self, model, other_args, expected_score):
+        base_url = DEFAULT_URL_FOR_TEST
+        other_args = other_args or []
+
+        process = popen_launch_server(
+            model,
+            base_url,
+            timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
+            other_args=other_args,
+        )
+
+        try:
+            args = SimpleNamespace(
+                base_url=base_url,
+                model=model,
+                eval_name="mmlu",
+                num_examples=64,
+                num_threads=32,
+                temperature=0.1,
+            )
+
+            metrics = run_eval(args)
+            self.assertGreaterEqual(metrics["score"], expected_score)
+        finally:
+            kill_process_tree(process.pid)
+
+    def test_mmlu_offline_only(self):
+        """Test with offline quantization only."""
+        self._run_test(
+            model=DEFAULT_FP8_MODEL_NAME_FOR_MODELOPT_QUANT_ACCURACY_TEST,
+            other_args=[
+                "--quantization",
+                "modelopt",
+                "--revision",
+                DEFAULT_FP8_MODEL_NAME_FOR_MODELOPT_QUANT_ACCURACY_TEST_REVISION,
+            ],
+            expected_score=0.64,
+        )
+
+
 if __name__ == "__main__":
     unittest.main()