[Bugfix] Fix quark fp8 format loading on AMD GPUs (#12612)

Signed-off-by: Felix Marty <felmarty@amd.com>
Signed-off-by: kewang2 <kewang2@amd.com>
Co-authored-by: kewang2 <kewang2@amd.com>

tests/quantization/test_quark.py

@@ -5,6 +5,7 @@ Run `pytest tests/quantization/test_quark.py`.
 """
 
 import pytest
+import torch
 
 from vllm.model_executor.layers.quantization.quark.quark import (  # noqa: E501
     QuarkLinearMethod, QuarkW8A8Fp8, QuarkW8A8Int8)
@@ -63,3 +64,28 @@ def test_quark_int8_w_per_tensor_a_per_tensor(vllm_runner, tp):
 
         output = llm.generate_greedy("Hello my name is", max_tokens=20)
         assert output
+
+
+def test_quark_fp8_parity(vllm_runner):
+    quark_model_id = "amd-quark/llama-tiny-fp8-quark-quant-method"
+    fp8_model_id = "amd-quark/llama-tiny-fp8-quant-method"
+
+    llm_kwargs = {
+        "tensor_parallel_size": 1,
+        "enforce_eager": True,
+        "gpu_memory_utilization": 0.1
+    }
+    with (vllm_runner(quark_model_id, **llm_kwargs) as
+          quark_handle, vllm_runner(fp8_model_id, **llm_kwargs) as fp8_handle):
+        quark_model = (quark_handle.model.llm_engine.model_executor.
+                       driver_worker.model_runner.model)
+        quark_state_dict = quark_model.state_dict()
+
+        fp8_model = (fp8_handle.model.llm_engine.model_executor.driver_worker.
+                     model_runner.model)
+        fp8_state_dict = fp8_model.state_dict()
+
+    assert fp8_state_dict.keys() == quark_state_dict.keys()
+
+    for key in fp8_state_dict:
+        assert torch.equal(fp8_state_dict[key], quark_state_dict[key])