[Benchmark] Improvements to attention benchmark script (#37115)

Signed-off-by: wzhao18 <wzhao18.sz@gmail.com>

benchmarks/attention_benchmarks/benchmark.py

@@ -47,6 +47,8 @@ from common import (
     is_mla_backend,
 )
 
+from vllm.v1.worker.workspace import init_workspace_manager
+
 
 def run_standard_attention_benchmark(config: BenchmarkConfig) -> BenchmarkResult:
     """Run standard attention benchmark (Flash/Triton/FlashInfer)."""
@@ -462,7 +464,7 @@ def main():
     parser.add_argument(
         "--batch-specs",
         nargs="+",
-        default=["q2k", "8q1s1k"],
+        default=None,
         help="Batch specifications using extended grammar",
     )
 
@@ -478,6 +480,21 @@ def main():
     parser.add_argument("--repeats", type=int, default=1, help="Repetitions")
     parser.add_argument("--warmup-iters", type=int, default=3, help="Warmup iterations")
     parser.add_argument("--profile-memory", action="store_true", help="Profile memory")
+    parser.add_argument(
+        "--kv-cache-dtype",
+        default="auto",
+        choices=["auto", "fp8"],
+        help="KV cache dtype: auto or fp8",
+    )
+    parser.add_argument(
+        "--cuda-graphs",
+        action=argparse.BooleanOptionalAction,
+        default=True,
+        help=(
+            "Launch kernels with CUDA graphs to eliminate CPU overhead"
+            "in measurements (default: True)"
+        ),
+    )
 
     # Parameter sweep (use YAML config for advanced sweeps)
     parser.add_argument(
@@ -536,21 +553,24 @@ def main():
 
         # Batch specs and sizes
         # Support both explicit batch_specs and generated batch_spec_ranges
-        if "batch_spec_ranges" in yaml_config:
-            # Generate batch specs from ranges
-            generated_specs = generate_batch_specs_from_ranges(
-                yaml_config["batch_spec_ranges"]
-            )
-            # Combine with any explicit batch_specs
-            if "batch_specs" in yaml_config:
-                args.batch_specs = yaml_config["batch_specs"] + generated_specs
-            else:
-                args.batch_specs = generated_specs
-            console.print(
-                f"[dim]Generated {len(generated_specs)} batch specs from ranges[/]"
-            )
-        elif "batch_specs" in yaml_config:
-            args.batch_specs = yaml_config["batch_specs"]
+        # CLI --batch-specs takes precedence over YAML when provided.
+        cli_batch_specs_provided = args.batch_specs is not None
+        if not cli_batch_specs_provided:
+            if "batch_spec_ranges" in yaml_config:
+                # Generate batch specs from ranges
+                generated_specs = generate_batch_specs_from_ranges(
+                    yaml_config["batch_spec_ranges"]
+                )
+                # Combine with any explicit batch_specs
+                if "batch_specs" in yaml_config:
+                    args.batch_specs = yaml_config["batch_specs"] + generated_specs
+                else:
+                    args.batch_specs = generated_specs
+                console.print(
+                    f"[dim]Generated {len(generated_specs)} batch specs from ranges[/]"
+                )
+            elif "batch_specs" in yaml_config:
+                args.batch_specs = yaml_config["batch_specs"]
 
         if "batch_sizes" in yaml_config:
             args.batch_sizes = yaml_config["batch_sizes"]
@@ -575,6 +595,10 @@ def main():
             args.warmup_iters = yaml_config["warmup_iters"]
         if "profile_memory" in yaml_config:
             args.profile_memory = yaml_config["profile_memory"]
+        if "kv_cache_dtype" in yaml_config:
+            args.kv_cache_dtype = yaml_config["kv_cache_dtype"]
+        if "cuda_graphs" in yaml_config:
+            args.cuda_graphs = yaml_config["cuda_graphs"]
 
         # Parameter sweep configuration
         if "parameter_sweep" in yaml_config:
@@ -629,12 +653,18 @@ def main():
     # Determine backends
     backends = args.backends or ([args.backend] if args.backend else ["flash"])
     prefill_backends = getattr(args, "prefill_backends", None)
+    if not args.batch_specs:
+        args.batch_specs = ["q2k", "8q1s1k"]
     console.print(f"Backends: {', '.join(backends)}")
     if prefill_backends:
         console.print(f"Prefill backends: {', '.join(prefill_backends)}")
     console.print(f"Batch specs: {', '.join(args.batch_specs)}")
+    console.print(f"KV cache dtype: {args.kv_cache_dtype}")
+    console.print(f"CUDA graphs: {args.cuda_graphs}")
     console.print()
 
+    init_workspace_manager(args.device)
+
     # Run benchmarks
     all_results = []
 
@@ -687,6 +717,8 @@ def main():
                         repeats=args.repeats,
                         warmup_iters=args.warmup_iters,
                         profile_memory=args.profile_memory,
+                        kv_cache_dtype=args.kv_cache_dtype,
+                        use_cuda_graphs=args.cuda_graphs,
                     )
 
                     # Add decode pipeline config
@@ -839,6 +871,8 @@ def main():
             "repeats": args.repeats,
             "warmup_iters": args.warmup_iters,
             "profile_memory": args.profile_memory,
+            "kv_cache_dtype": args.kv_cache_dtype,
+            "use_cuda_graphs": args.cuda_graphs,
         }
         all_results = run_model_parameter_sweep(
             backends,
@@ -861,6 +895,8 @@ def main():
             "repeats": args.repeats,
             "warmup_iters": args.warmup_iters,
             "profile_memory": args.profile_memory,
+            "kv_cache_dtype": args.kv_cache_dtype,
+            "use_cuda_graphs": args.cuda_graphs,
         }
         all_results = run_parameter_sweep(
             backends, args.batch_specs, base_config_args, args.parameter_sweep, console
@@ -891,6 +927,8 @@ def main():
                             repeats=args.repeats,
                             warmup_iters=args.warmup_iters,
                             profile_memory=args.profile_memory,
+                            kv_cache_dtype=args.kv_cache_dtype,
+                            use_cuda_graphs=args.cuda_graphs,
                         )
 
                         result = run_benchmark(config)

benchmarks/attention_benchmarks/common.py

@@ -213,6 +213,9 @@ class BenchmarkConfig:
     profile_memory: bool = False
     use_cuda_graphs: bool = False
 
+    # "auto" or "fp8"
+    kv_cache_dtype: str = "auto"
+
     # MLA-specific
     prefill_backend: str | None = None
     kv_lora_rank: int | None = None
@@ -369,6 +372,7 @@ class ResultsFormatter:
                     "backend",
                     "batch_spec",
                     "num_layers",
+                    "kv_cache_dtype",
                     "mean_time",
                     "std_time",
                     "throughput",
@@ -382,6 +386,7 @@ class ResultsFormatter:
                         "backend": r.config.backend,
                         "batch_spec": r.config.batch_spec,
                         "num_layers": r.config.num_layers,
+                        "kv_cache_dtype": r.config.kv_cache_dtype,
                         "mean_time": r.mean_time,
                         "std_time": r.std_time,
                         "throughput": r.throughput_tokens_per_sec or 0,

benchmarks/attention_benchmarks/configs/mla_mixed_batch.yaml

@@ -30,9 +30,9 @@ batch_specs:
   - "2q16k_32q1s4k"         # 2 very large prefill + 32 decode
 
   # Context extension + decode
-  - "2q1kkv2k_16q1s1k"       # 2 extend + 16 decode
-  - "4q2kkv4k_32q1s2k"       # 4 extend + 32 decode
-  - "2q1kkv8k_32q1s2k"       # 2 large extend + 32 decode
+  - "2q1ks2k_16q1s1k"       # 2 extend + 16 decode
+  - "4q2ks4k_32q1s2k"       # 4 extend + 32 decode
+  - "2q1ks8k_32q1s2k"       # 2 large extend + 32 decode
 
   # Explicitly chunked prefill
   - "q8k"           # 8k prefill with chunking hint

benchmarks/attention_benchmarks/configs/mla_sparse_decode.yaml

+# MLA decode-only benchmark configuration
+
+model:
+  name: "deepseek-v3"
+  num_layers: 60
+  num_q_heads: 128  # Base value, can be swept for TP simulation
+  num_kv_heads: 1  # MLA uses single latent KV
+  head_dim: 576
+  kv_lora_rank: 512
+  qk_nope_head_dim: 128
+  qk_rope_head_dim: 64
+  v_head_dim: 128
+  block_size: 128  # CUTLASS MLA and FlashAttn MLA use 128
+
+# Model parameter sweep: simulate tensor parallelism by varying num_q_heads
+# TP=1: 128 heads, TP=2: 64 heads, TP=4: 32 heads, TP=8: 16 heads
+model_parameter_sweep:
+  param_name: "num_q_heads"
+  values: [128, 64, 32, 16]
+  label_format: "{backend}_{value}h"
+
+batch_specs:
+  # Small batches, varying sequence lengths
+  - "16q1s512"     # 16 requests, 512 KV cache
+  - "16q1s1k"      # 16 requests, 1k KV cache
+  - "16q1s2k"      # 16 requests, 2k KV cache
+  - "16q1s4k"      # 16 requests, 4k KV cache
+
+  # Medium batches
+  - "32q1s1k"      # 32 requests, 1k KV cache
+  - "32q1s2k"      # 32 requests, 2k KV cache
+  - "32q1s4k"      # 32 requests, 4k KV cache
+  - "32q1s8k"      # 32 requests, 8k KV cache
+
+  # Large batches
+  - "64q1s1k"      # 64 requests, 1k KV cache
+  - "64q1s2k"      # 64 requests, 2k KV cache
+  - "64q1s4k"      # 64 requests, 4k KV cache
+  - "64q1s8k"      # 64 requests, 8k KV cache
+
+  # Very large batches
+  - "128q1s1k"     # 128 requests, 1k KV cache
+  - "128q1s2k"     # 128 requests, 2k KV cache
+  - "128q1s4k"     # 128 requests, 4k KV cache
+  - "128q1s8k"     # 128 requests, 8k KV cache
+
+  # Long context
+  - "32q1s16k"     # 32 requests, 16k KV cache
+  - "32q1s32k"     # 32 requests, 32k KV cache
+
+backends:
+  - FLASHMLA_SPARSE
+  - FLASHINFER_MLA_SPARSE
+
+device: "cuda:0"
+repeats: 100
+warmup_iters: 10
+profile_memory: true

benchmarks/attention_benchmarks/mla_runner.py

@@ -60,9 +60,11 @@ def create_minimal_vllm_config(
     model_name: str = "deepseek-v3",
     block_size: int = 128,
     max_num_seqs: int = 256,
+    max_num_batched_tokens: int = 8192,
     mla_dims: dict | None = None,
     index_topk: int | None = None,
     prefill_backend: str | None = None,
+    kv_cache_dtype: str = "auto",
 ) -> VllmConfig:
     """
     Create minimal VllmConfig for MLA benchmarks.
@@ -149,13 +151,13 @@ def create_minimal_vllm_config(
     cache_config = CacheConfig(
         block_size=block_size,
         gpu_memory_utilization=0.9,
-        cache_dtype="auto",
+        cache_dtype=kv_cache_dtype,
         enable_prefix_caching=False,
     )
 
     scheduler_config = SchedulerConfig(
         max_num_seqs=max_num_seqs,
-        max_num_batched_tokens=8192,
+        max_num_batched_tokens=max(max_num_batched_tokens, max_num_seqs),
         max_model_len=32768,
         is_encoder_decoder=False,
         enable_chunked_prefill=True,
@@ -535,6 +537,7 @@ def _create_backend_impl(
     device: torch.device,
     max_num_tokens: int = 8192,
     index_topk: int | None = None,
+    kv_cache_dtype: str = "auto",
 ):
     """
     Create backend implementation instance.
@@ -583,7 +586,7 @@ def _create_backend_impl(
         "num_kv_heads": mla_dims["num_kv_heads"],
         "alibi_slopes": None,
         "sliding_window": None,
-        "kv_cache_dtype": "auto",
+        "kv_cache_dtype": kv_cache_dtype,
         "logits_soft_cap": None,
         "attn_type": "decoder",
         "kv_sharing_target_layer_name": None,
@@ -701,6 +704,7 @@ def _run_single_benchmark(
     mla_dims: dict,
     device: torch.device,
     indexer=None,
+    kv_cache_dtype: str | None = None,
 ) -> BenchmarkResult:
     """
     Run a single benchmark iteration.
@@ -734,49 +738,124 @@ def _run_single_benchmark(
     )
 
     # Create KV cache
-    kv_cache = torch.zeros(
-        num_blocks,
-        block_size,
-        mla_dims["kv_lora_rank"] + mla_dims["qk_rope_head_dim"],
-        device=device,
-        dtype=torch.bfloat16,
-    )
+    if kv_cache_dtype is None:
+        kv_cache_dtype = getattr(config, "kv_cache_dtype", "auto")
+    head_size = mla_dims["kv_lora_rank"] + mla_dims["qk_rope_head_dim"]
+    if kv_cache_dtype == "fp8_ds_mla":
+        # FlashMLA sparse custom format: 656 bytes per token, stored as uint8.
+        # Layout: kv_lora_rank fp8 bytes + 4 float32 tile scales
+        #         + 2*rope_dim bf16 bytes
+        # = 512 + 16 + 128 = 656 bytes for DeepSeek dims.
+        kv_cache = torch.zeros(
+            num_blocks,
+            block_size,
+            656,
+            device=device,
+            dtype=torch.uint8,
+        )
+    elif kv_cache_dtype == "fp8":
+        from vllm.platforms import current_platform
 
-    # Create input tensors for both decode and prefill modes
-    decode_inputs, prefill_inputs = _create_input_tensors(
-        total_q,
-        mla_dims,
-        backend_cfg["query_format"],
-        device,
-        torch.bfloat16,
-    )
+        kv_cache = torch.zeros(
+            num_blocks,
+            block_size,
+            head_size,
+            device=device,
+            dtype=torch.uint8,
+        ).view(current_platform.fp8_dtype())
+    else:
+        kv_cache = torch.zeros(
+            num_blocks,
+            block_size,
+            head_size,
+            device=device,
+            dtype=torch.bfloat16,
+        )
 
     # Fill indexer with random indices for sparse backends
     is_sparse = backend_cfg.get("is_sparse", False)
     if is_sparse and indexer is not None:
         indexer.fill_random_indices(total_q, max_kv_len)
 
-    # Determine which forward method to use based on metadata
-    if metadata.decode is not None:
-        forward_fn = lambda: impl.forward_mqa(decode_inputs, kv_cache, metadata, layer)
-    elif metadata.prefill is not None:
-        forward_fn = lambda: impl.forward_mha(
-            prefill_inputs["q"],
-            prefill_inputs["k_c_normed"],
-            prefill_inputs["k_pe"],
-            kv_cache,
-            metadata,
-            prefill_inputs["k_scale"],
-            prefill_inputs["output"],
-        )
-    else:
+    # Determine which forward methods to use based on metadata.
+    # Sparse MLA backends always use forward_mqa
+    has_decode = is_sparse or getattr(metadata, "decode", None) is not None
+    has_prefill = not is_sparse and getattr(metadata, "prefill", None) is not None
+    if not has_decode and not has_prefill:
         raise RuntimeError("Metadata has neither decode nor prefill metadata")
 
+    num_decode = (
+        metadata.num_decode_tokens
+        if (has_decode and has_prefill)
+        else total_q
+        if has_decode
+        else 0
+    )
+    num_prefill = total_q - num_decode
+
+    # Some backends requires fp8 queries when using fp8 KV cache.
+    is_fp8_kvcache = kv_cache_dtype.startswith("fp8")
+    quantize_query = is_fp8_kvcache and getattr(
+        impl, "supports_quant_query_input", False
+    )
+
+    # quantize_query forces concat format
+    query_fmt = "concat" if quantize_query else backend_cfg["query_format"]
+
+    # Create decode query tensors
+    if has_decode:
+        decode_inputs, _ = _create_input_tensors(
+            num_decode, mla_dims, query_fmt, device, torch.bfloat16
+        )
+        # Cast decode query to fp8 if the backend supports it
+        if quantize_query:
+            from vllm.platforms import current_platform
+
+            if isinstance(decode_inputs, tuple):
+                decode_inputs = torch.cat(list(decode_inputs), dim=-1)
+            decode_inputs = decode_inputs.to(current_platform.fp8_dtype())
+
+    # Create prefill input tensors
+    if has_prefill:
+        _, prefill_inputs = _create_input_tensors(
+            num_prefill, mla_dims, query_fmt, device, torch.bfloat16
+        )
+
+    # Build forward function
+    def forward_fn():
+        results = []
+        if has_decode:
+            results.append(impl.forward_mqa(decode_inputs, kv_cache, metadata, layer))
+        if has_prefill:
+            results.append(
+                impl.forward_mha(
+                    prefill_inputs["q"],
+                    prefill_inputs["k_c_normed"],
+                    prefill_inputs["k_pe"],
+                    kv_cache,
+                    metadata,
+                    prefill_inputs["k_scale"],
+                    prefill_inputs["output"],
+                )
+            )
+        return results[0] if len(results) == 1 else tuple(results)
+
     # Warmup
     for _ in range(config.warmup_iters):
         forward_fn()
     torch.accelerator.synchronize()
 
+    # Optionally capture a CUDA graph after warmup.
+    # Graph replay eliminates CPU launch overhead so timings reflect pure
+    # kernel time.
+    if config.use_cuda_graphs:
+        graph = torch.cuda.CUDAGraph()
+        with torch.cuda.graph(graph):
+            forward_fn()
+        benchmark_fn = graph.replay
+    else:
+        benchmark_fn = forward_fn
+
     # Benchmark
     times = []
     for _ in range(config.repeats):
@@ -785,7 +864,7 @@ def _run_single_benchmark(
 
         start.record()
         for _ in range(config.num_layers):
-            forward_fn()
+            benchmark_fn()
         end.record()
 
         torch.accelerator.synchronize()
@@ -852,13 +931,30 @@ def _run_mla_benchmark_batched(
     # Determine if this is a sparse backend
     is_sparse = backend_cfg.get("is_sparse", False)
 
+    # Extract kv_cache_dtype from the first config
+    kv_cache_dtype = getattr(first_config, "kv_cache_dtype", "auto")
+
+    # FlashMLA sparse only supports "fp8_ds_mla" internally (not generic "fp8").
+    # Remap here so the user can pass --kv-cache-dtype fp8 regardless of backend.
+    if backend.upper() == "FLASHMLA_SPARSE" and kv_cache_dtype == "fp8":
+        kv_cache_dtype = "fp8_ds_mla"
+
+    # Compute max total_q across all configs so the metadata builder buffer
+    # and scheduler config are large enough for all batch specs.
+    max_total_q = max(
+        sum(r.q_len for r in parse_batch_spec(cfg.batch_spec))
+        for cfg, *_ in configs_with_params
+    )
+
     # Create and set vLLM config for MLA (reused across all benchmarks)
     vllm_config = create_minimal_vllm_config(
         model_name="deepseek-v3",  # Used only for model path
         block_size=block_size,
+        max_num_batched_tokens=max_total_q,
         mla_dims=mla_dims,  # Use custom dims from config or default
         index_topk=index_topk if is_sparse else None,
         prefill_backend=prefill_backend,
+        kv_cache_dtype=kv_cache_dtype,
     )
 
     results = []
@@ -883,7 +979,9 @@ def _run_mla_benchmark_batched(
             mla_dims,
             vllm_config,
             device,
+            max_num_tokens=max_total_q,
             index_topk=index_topk if is_sparse else None,
+            kv_cache_dtype=kv_cache_dtype,
         )
 
         # Verify the actual prefill backend matches what was requested
@@ -942,6 +1040,7 @@ def _run_mla_benchmark_batched(
                     mla_dims,
                     device,
                     indexer=indexer,
+                    kv_cache_dtype=kv_cache_dtype,
                 )
                 results.append(result)
 

benchmarks/attention_benchmarks/runner.py

@@ -140,7 +140,7 @@ def _create_vllm_config(
 
     cache_config = CacheConfig(
         block_size=config.block_size,
-        cache_dtype="auto",
+        cache_dtype=config.kv_cache_dtype,
     )
     cache_config.num_gpu_blocks = max_num_blocks
     cache_config.num_cpu_blocks = 0
@@ -215,7 +215,7 @@ def _create_backend_impl(
         num_kv_heads=config.num_kv_heads,
         alibi_slopes=None,
         sliding_window=None,
-        kv_cache_dtype="auto",
+        kv_cache_dtype=config.kv_cache_dtype,
     )
 
     kv_cache_spec = FullAttentionSpec(
@@ -288,12 +288,22 @@ def _create_input_tensors(
     total_q: int,
     device: torch.device,
     dtype: torch.dtype,
+    quantize_query: bool = False,
 ) -> tuple:
-    """Create Q, K, V input tensors for all layers."""
+    """Create Q, K, V input tensors for all layers.
+
+    When quantize_query is True, queries are cast to fp8 to match backends
+    that require query/key/value dtype consistency.
+    """
+    q_dtype = dtype
+    if quantize_query:
+        from vllm.platforms import current_platform
+
+        q_dtype = current_platform.fp8_dtype()
     q_list = [
         torch.randn(
             total_q, config.num_q_heads, config.head_dim, device=device, dtype=dtype
-        )
+        ).to(q_dtype)
         for _ in range(config.num_layers)
     ]
     k_list = [
@@ -344,10 +354,17 @@ def _create_kv_cache(
     # Compute inverse permutation to get back to logical view
     inv_order = [stride_order.index(i) for i in range(len(stride_order))]
 
+    # Use fp8 dtype for cache when requested.
+    cache_dtype = dtype
+    if config.kv_cache_dtype == "fp8":
+        from vllm.platforms import current_platform
+
+        cache_dtype = current_platform.fp8_dtype()
+
     cache_list = []
     for _ in range(config.num_layers):
         # Allocate in physical layout order (contiguous in memory)
-        cache = torch.zeros(*physical_shape, device=device, dtype=dtype)
+        cache = torch.zeros(*physical_shape, device=device, dtype=cache_dtype)
         # Permute to logical view
         cache = cache.permute(*inv_order)
         cache_list.append(cache)
@@ -392,6 +409,37 @@ def _run_single_benchmark(
             )
     torch.accelerator.synchronize()
 
+    # Optionally capture a CUDA graph after warmup.
+    # Graph replay eliminates CPU launch overhead so timings reflect pure
+    # kernel time.
+    if config.use_cuda_graphs:
+        graph = torch.cuda.CUDAGraph()
+        with torch.cuda.graph(graph):
+            for i in range(config.num_layers):
+                impl.forward(
+                    layer,
+                    q_list[i],
+                    k_list[i],
+                    v_list[i],
+                    cache_list[i],
+                    attn_metadata,
+                    output=out,
+                )
+        benchmark_fn = graph.replay
+    else:
+
+        def benchmark_fn():
+            for i in range(config.num_layers):
+                impl.forward(
+                    layer,
+                    q_list[i],
+                    k_list[i],
+                    v_list[i],
+                    cache_list[i],
+                    attn_metadata,
+                    output=out,
+                )
+
     # Benchmark
     times = []
     for _ in range(config.repeats):
@@ -399,16 +447,7 @@ def _run_single_benchmark(
         end = torch.cuda.Event(enable_timing=True)
 
         start.record()
-        for i in range(config.num_layers):
-            impl.forward(
-                layer,
-                q_list[i],
-                k_list[i],
-                v_list[i],
-                cache_list[i],
-                attn_metadata,
-                output=out,
-            )
+        benchmark_fn()
         end.record()
 
         torch.accelerator.synchronize()
@@ -502,8 +541,12 @@ def run_attention_benchmark(config: BenchmarkConfig) -> BenchmarkResult:
                 common_attn_metadata=common_metadata,
             )
 
+            # Only quantize queries when the impl supports it
+            quantize_query = config.kv_cache_dtype.startswith("fp8") and getattr(
+                impl, "supports_quant_query_input", False
+            )
             q_list, k_list, v_list = _create_input_tensors(
-                config, total_q, device, dtype
+                config, total_q, device, dtype, quantize_query=quantize_query
             )
 
             cache_list = _create_kv_cache(