support bitsandbytes 8-bit and FP4 quantized models (vllm-project#7445)

tests/conftest.py

@@ -209,8 +209,14 @@ class HfRunner:
 
     def wrap_device(self, input: _T) -> _T:
         if not is_cpu():
+            # Check if the input is already on the GPU
+            if hasattr(input, 'device') and input.device.type == "cuda":
+                return input  # Already on GPU, no need to move
             return input.to("cuda")
         else:
+            # Check if the input is already on the CPU
+            if hasattr(input, 'device') and input.device.type == "cpu":
+                return input  # Already on CPU, no need to move
             return input.to("cpu")
 
     def __init__(

tests/quantization/test_bitsandbytes.py

@@ -2,85 +2,115 @@
 
 Run `pytest tests/quantization/test_bitsandbytes.py`.
 '''
+
+import gc
+
 import pytest
 import torch
 
 from tests.quantization.utils import is_quant_method_supported
-from vllm import SamplingParams
 
-models_to_test = [
+models_4bit_to_test = [
     ('huggyllama/llama-7b', 'quantize model inflight'),
-    ('lllyasviel/omost-llama-3-8b-4bits', 'read pre-quantized model'),
 ]
 
+models_pre_qaunt_4bit_to_test = [
+    ('lllyasviel/omost-llama-3-8b-4bits',
+     'read pre-quantized 4-bit NF4 model'),
+    ('PrunaAI/Einstein-v6.1-Llama3-8B-bnb-4bit-smashed',
+     'read pre-quantized 4-bit FP4 model'),
+]
+
+models_pre_quant_8bit_to_test = [
+    ('meta-llama/Llama-Guard-3-8B-INT8', 'read pre-quantized 8-bit model'),
+]
+
+
+@pytest.mark.skipif(not is_quant_method_supported("bitsandbytes"),
+                    reason='bitsandbytes is not supported on this GPU type.')
+@pytest.mark.parametrize("model_name, description", models_4bit_to_test)
+def test_load_4bit_bnb_model(hf_runner, vllm_runner, example_prompts,
+                             model_name, description) -> None:
+
+    hf_model_kwargs = {"load_in_4bit": True}
+    validate_generated_texts(hf_runner, vllm_runner, example_prompts[:1],
+                             model_name, hf_model_kwargs)
+
+
+@pytest.mark.skipif(not is_quant_method_supported("bitsandbytes"),
+                    reason='bitsandbytes is not supported on this GPU type.')
+@pytest.mark.parametrize("model_name, description",
+                         models_pre_qaunt_4bit_to_test)
+def test_load_pre_quant_4bit_bnb_model(hf_runner, vllm_runner, example_prompts,
+                                       model_name, description) -> None:
+
+    validate_generated_texts(hf_runner, vllm_runner, example_prompts[:1],
+                             model_name)
+
 
 @pytest.mark.skipif(not is_quant_method_supported("bitsandbytes"),
                     reason='bitsandbytes is not supported on this GPU type.')
-@pytest.mark.parametrize("model_name, description", models_to_test)
-def test_load_bnb_model(vllm_runner, model_name, description) -> None:
+@pytest.mark.parametrize("model_name, description",
+                         models_pre_quant_8bit_to_test)
+def test_load_8bit_bnb_model(hf_runner, vllm_runner, example_prompts,
+                             model_name, description) -> None:
+
+    validate_generated_texts(hf_runner, vllm_runner, example_prompts[:1],
+                             model_name)
+
+
+def log_generated_texts(prompts, outputs, runner_name):
+    logged_texts = []
+    for i, (_, generated_text) in enumerate(outputs):
+        log_entry = {
+            "prompt": prompts[i],
+            "runner_name": runner_name,
+            "generated_text": generated_text,
+        }
+        logged_texts.append(log_entry)
+    return logged_texts
+
+
+def validate_generated_texts(hf_runner,
+                             vllm_runner,
+                             prompts,
+                             model_name,
+                             hf_model_kwargs=None):
+
+    if hf_model_kwargs is None:
+        hf_model_kwargs = {}
+
+    # Run with HF runner
+    with hf_runner(model_name, model_kwargs=hf_model_kwargs) as llm:
+        hf_outputs = llm.generate_greedy(prompts, 8)
+        hf_logs = log_generated_texts(prompts, hf_outputs, "HfRunner")
+
+    # Clean up the GPU memory for the next test
+    torch.cuda.synchronize()
+    gc.collect()
+    torch.cuda.empty_cache()
+
+    #Run with vLLM runner
     with vllm_runner(model_name,
                      quantization='bitsandbytes',
                      load_format='bitsandbytes',
-                     enforce_eager=True) as llm:
-        model = llm.model.llm_engine.model_executor.driver_worker.model_runner.model  # noqa: E501
-
-        # check the weights in MLP & SelfAttention are quantized to torch.uint8
-        qweight = model.model.layers[0].mlp.gate_up_proj.qweight
-        assert qweight.dtype == torch.uint8, (
-            f'Expected gate_up_proj dtype torch.uint8 but got {qweight.dtype}')
-
-        qweight = model.model.layers[0].mlp.down_proj.qweight
-        assert qweight.dtype == torch.uint8, (
-            f'Expected down_proj dtype torch.uint8 but got {qweight.dtype}')
-
-        qweight = model.model.layers[0].self_attn.o_proj.qweight
-        assert qweight.dtype == torch.uint8, (
-            f'Expected o_proj dtype torch.uint8 but got {qweight.dtype}')
-
-        qweight = model.model.layers[0].self_attn.qkv_proj.qweight
-        assert qweight.dtype == torch.uint8, (
-            f'Expected qkv_proj dtype torch.uint8 but got {qweight.dtype}')
-
-        # some weights should not be quantized
-        weight = model.lm_head.weight
-        assert weight.dtype != torch.uint8, (
-            'lm_head weight dtype should not be torch.uint8')
-
-        weight = model.model.embed_tokens.weight
-        assert weight.dtype != torch.uint8, (
-            'embed_tokens weight dtype should not be torch.uint8')
-
-        weight = model.model.layers[0].input_layernorm.weight
-        assert weight.dtype != torch.uint8, (
-            'input_layernorm weight dtype should not be torch.uint8')
-
-        weight = model.model.layers[0].post_attention_layernorm.weight
-        assert weight.dtype != torch.uint8, (
-            'input_layernorm weight dtype should not be torch.uint8')
-
-        # check the output of the model is expected
-        sampling_params = SamplingParams(temperature=0.0,
-                                         logprobs=1,
-                                         prompt_logprobs=1,
-                                         max_tokens=8)
-
-        prompts = ['That which does not kill us', 'To be or not to be,']
-        expected_outputs = [
-            'That which does not kill us makes us stronger.',
-            'To be or not to be, that is the question.'
-        ]
-        outputs = llm.generate(prompts, sampling_params=sampling_params)
-        assert len(outputs) == len(prompts)
-
-        for index in range(len(outputs)):
-            # compare the first line of the output
-            actual_output = outputs[index][1][0].split('\n', 1)[0]
-            expected_output = expected_outputs[index].split('\n', 1)[0]
-
-            assert len(actual_output) >= len(expected_output), (
-                f'Actual {actual_output} should be larger than or equal to '
-                f'expected {expected_output}')
-            actual_output = actual_output[:len(expected_output)]
-
-            assert actual_output == expected_output, (
-                f'Expected: {expected_output}, but got: {actual_output}')
+                     enforce_eager=True,
+                     gpu_memory_utilization=0.8) as llm:
+        vllm_outputs = llm.generate_greedy(prompts, 8)
+        vllm_logs = log_generated_texts(prompts, vllm_outputs, "VllmRunner")
+
+    # Clean up the GPU memory for the next test
+    torch.cuda.synchronize()
+    gc.collect()
+    torch.cuda.empty_cache()
+
+    # Compare the generated strings
+    for hf_log, vllm_log in zip(hf_logs, vllm_logs):
+        hf_str = hf_log["generated_text"]
+        vllm_str = vllm_log["generated_text"]
+        prompt = hf_log["prompt"]
+        assert hf_str == vllm_str, (f"Model: {model_name}"
+                                    f"Mismatch between HF and vLLM outputs:\n"
+                                    f"Prompt: {prompt}\n"
+                                    f"HF Output: '{hf_str}'\n"
+                                    f"vLLM Output: '{vllm_str}'")

vllm/config.py

@@ -405,6 +405,8 @@ def verify_with_parallel_config(
             raise ValueError(
                 "BitAndBytes quantization with TP or PP is not supported yet.")
 
+        # Remove the constraint after the bitsandbytes issue is fixed:
+        # https://github.com/bitsandbytes-foundation/bitsandbytes/issues/1308
         if self.quantization == "bitsandbytes" and self.enforce_eager is False:
             logger.warning("CUDA graph is not supported on BitAndBytes yet, "
                            "fallback to the eager mode.")

vllm/model_executor/layers/linear.py

@@ -36,9 +36,9 @@ def adjust_marlin_shard(param, shard_size, shard_offset):
     return shard_size * marlin_tile_size, shard_offset * marlin_tile_size
 
 
-def adjust_bitsandbytes_shard(param: Parameter,
-                              qkv_offsets: Dict[str, Tuple[int, int]],
-                              loaded_shard_id: str) -> Tuple[int, int]:
+def adjust_bitsandbytes_4bit_shard(param: Parameter,
+                                   qkv_offsets: Dict[str, Tuple[int, int]],
+                                   loaded_shard_id: str) -> Tuple[int, int]:
     """Adjust the quantization offsets and sizes for BitsAndBytes sharding."""
 
     total, _ = qkv_offsets["total"]
@@ -505,8 +505,9 @@ def weight_loader(self,
                 shard_size, shard_offset = adjust_marlin_shard(
                     param, shard_size, shard_offset)
 
-            use_bitsandbytes = getattr(param, "use_bitsandbytes", False)
-            if use_bitsandbytes:
+            use_bitsandbytes_4bit = getattr(param, "use_bitsandbytes_4bit",
+                                            False)
+            if use_bitsandbytes_4bit:
                 shard_size = loaded_weight.shape[output_dim]
                 shard_offset = loaded_weight.shape[output_dim] * \
                     loaded_shard_id
@@ -858,8 +859,9 @@ def weight_loader(self,
                 shard_size, shard_offset = adjust_marlin_shard(
                     param, shard_size, shard_offset)
 
-            use_bitsandbytes = getattr(param, "use_bitsandbytes", False)
-            if use_bitsandbytes:
+            use_bitsandbytes_4bit = getattr(param, "use_bitsandbytes_4bit",
+                                            False)
+            if use_bitsandbytes_4bit:
                 orig_qkv_offsets = {
                     "q": (0, self.num_heads * self.head_size),
                     "k": (self.num_heads * self.head_size,
@@ -871,7 +873,7 @@ def weight_loader(self,
                     ((self.num_heads + 2 * self.num_kv_heads) * self.head_size,
                      0)
                 }
-                shard_size, shard_offset = adjust_bitsandbytes_shard(
+                shard_size, shard_offset = adjust_bitsandbytes_4bit_shard(
                     param, orig_qkv_offsets, loaded_shard_id)
 
             if is_gguf_weight: