fix xgrammar dependency conflict

benchmarks/attention_benchmarks/benchmark.py

@@ -59,7 +59,9 @@ def run_mla_benchmark(config: BenchmarkConfig, **kwargs) -> BenchmarkResult:
     """Run MLA benchmark with appropriate backend."""
     from mla_runner import run_mla_benchmark as run_mla
 
-    return run_mla(config.backend, config, **kwargs)
+    return run_mla(
+        config.backend, config, prefill_backend=config.prefill_backend, **kwargs
+    )
 
 
 def run_benchmark(config: BenchmarkConfig, **kwargs) -> BenchmarkResult:
@@ -440,14 +442,21 @@ def main():
     # Backend selection
     parser.add_argument(
         "--backends",
+        "--decode-backends",
         nargs="+",
-        help="Backends to benchmark (flash, triton, flashinfer, cutlass_mla, "
+        help="Decode backends to benchmark (flash, triton, flashinfer, cutlass_mla, "
         "flashinfer_mla, flashattn_mla, flashmla)",
     )
     parser.add_argument(
         "--backend",
         help="Single backend (alternative to --backends)",
     )
+    parser.add_argument(
+        "--prefill-backends",
+        nargs="+",
+        help="Prefill backends to compare (fa2, fa3, fa4). "
+        "Uses the first decode backend for impl construction.",
+    )
 
     # Batch specifications
     parser.add_argument(
@@ -502,7 +511,7 @@ def main():
 
         # Override args with YAML values, but CLI args take precedence
         # Check if CLI provided backends (they would be non-None and not default)
-        cli_backends_provided = args.backends is not None or args.backend is not None
+        cli_backends_provided = args.backend is not None or args.backends is not None
 
         # Backend(s) - only use YAML if CLI didn't specify
         if not cli_backends_provided:
@@ -512,6 +521,12 @@ def main():
             elif "backends" in yaml_config:
                 args.backends = yaml_config["backends"]
                 args.backend = None
+            elif "decode_backends" in yaml_config:
+                args.backends = yaml_config["decode_backends"]
+                args.backend = None
+
+        # Prefill backends (e.g., ["fa3", "fa4"])
+        args.prefill_backends = yaml_config.get("prefill_backends", None)
 
         # Check for special modes
         if "mode" in yaml_config:
@@ -613,7 +628,10 @@ def main():
 
     # Determine backends
     backends = args.backends or ([args.backend] if args.backend else ["flash"])
+    prefill_backends = getattr(args, "prefill_backends", None)
     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()
 
@@ -850,37 +868,93 @@ def main():
 
     else:
         # Normal mode: compare backends
-        total = len(backends) * len(args.batch_specs)
+        decode_results = []
+        prefill_results = []
 
-        with tqdm(total=total, desc="Benchmarking") as pbar:
-            for spec in args.batch_specs:
-                for backend in backends:
-                    config = BenchmarkConfig(
-                        backend=backend,
-                        batch_spec=spec,
-                        num_layers=args.num_layers,
-                        head_dim=args.head_dim,
-                        num_q_heads=args.num_q_heads,
-                        num_kv_heads=args.num_kv_heads,
-                        block_size=args.block_size,
-                        device=args.device,
-                        repeats=args.repeats,
-                        warmup_iters=args.warmup_iters,
-                        profile_memory=args.profile_memory,
-                    )
+        # Run decode backend comparison
+        if not prefill_backends:
+            # No prefill backends specified: compare decode backends as before
+            total = len(backends) * len(args.batch_specs)
 
-                    result = run_benchmark(config)
-                    all_results.append(result)
+            with tqdm(total=total, desc="Benchmarking") as pbar:
+                for spec in args.batch_specs:
+                    for backend in backends:
+                        config = BenchmarkConfig(
+                            backend=backend,
+                            batch_spec=spec,
+                            num_layers=args.num_layers,
+                            head_dim=args.head_dim,
+                            num_q_heads=args.num_q_heads,
+                            num_kv_heads=args.num_kv_heads,
+                            block_size=args.block_size,
+                            device=args.device,
+                            repeats=args.repeats,
+                            warmup_iters=args.warmup_iters,
+                            profile_memory=args.profile_memory,
+                        )
 
-                    if not result.success:
-                        console.print(f"[red]Error {backend} {spec}: {result.error}[/]")
+                        result = run_benchmark(config)
+                        decode_results.append(result)
 
-                    pbar.update(1)
+                        if not result.success:
+                            console.print(
+                                f"[red]Error {backend} {spec}: {result.error}[/]"
+                            )
 
-        # Display results
-        console.print("\n[bold green]Results:[/]")
-        formatter = ResultsFormatter(console)
-        formatter.print_table(all_results, backends)
+                        pbar.update(1)
+
+            console.print("\n[bold green]Results:[/]")
+            formatter = ResultsFormatter(console)
+            formatter.print_table(decode_results, backends)
+
+        # Run prefill backend comparison
+        if prefill_backends:
+            # Use first decode backend for impl construction
+            decode_backend = backends[0]
+            total = len(prefill_backends) * len(args.batch_specs)
+
+            console.print(
+                f"[yellow]Prefill comparison mode: "
+                f"using {decode_backend} for decode impl[/]"
+            )
+
+            with tqdm(total=total, desc="Prefill benchmarking") as pbar:
+                for spec in args.batch_specs:
+                    for pb in prefill_backends:
+                        config = BenchmarkConfig(
+                            backend=decode_backend,
+                            batch_spec=spec,
+                            num_layers=args.num_layers,
+                            head_dim=args.head_dim,
+                            num_q_heads=args.num_q_heads,
+                            num_kv_heads=args.num_kv_heads,
+                            block_size=args.block_size,
+                            device=args.device,
+                            repeats=args.repeats,
+                            warmup_iters=args.warmup_iters,
+                            profile_memory=args.profile_memory,
+                            prefill_backend=pb,
+                        )
+
+                        result = run_benchmark(config)
+
+                        # Label result with prefill backend name for display
+                        labeled_config = replace(result.config, backend=pb)
+                        result = replace(result, config=labeled_config)
+                        prefill_results.append(result)
+
+                        if not result.success:
+                            console.print(f"[red]Error {pb} {spec}: {result.error}[/]")
+
+                        pbar.update(1)
+
+            console.print("\n[bold green]Prefill Backend Results:[/]")
+            formatter = ResultsFormatter(console)
+            formatter.print_table(
+                prefill_results, prefill_backends, compare_to_fastest=True
+            )
+
+        all_results = decode_results + prefill_results
 
     # Save results
     if all_results:

benchmarks/attention_benchmarks/common.py

@@ -77,6 +77,7 @@ def __init__(self, num_heads: int, qk_nope_head_dim: int, v_head_dim: int):
         self.qk_nope_head_dim = qk_nope_head_dim
         self.v_head_dim = v_head_dim
         self.out_dim = qk_nope_head_dim + v_head_dim
+        self.weight = torch.empty(0, dtype=torch.bfloat16)
 
     def __call__(self, x: torch.Tensor) -> tuple[torch.Tensor]:
         """
@@ -213,6 +214,7 @@ class BenchmarkConfig:
     use_cuda_graphs: bool = False
 
     # MLA-specific
+    prefill_backend: str | None = None
     kv_lora_rank: int | None = None
     qk_nope_head_dim: int | None = None
     qk_rope_head_dim: int | None = None

benchmarks/attention_benchmarks/configs/mla_prefill.yaml

@@ -1,4 +1,19 @@
-# MLA prefill-only benchmark configuration for sparse backends
+# MLA prefill backend comparison
+#
+# Compares all available MLA prefill backends:
+#   FA backends:  fa2, fa3, fa4 (FlashAttention versions)
+#   Non-FA:       flashinfer, cudnn, trtllm (Blackwell-only, require flashinfer)
+#
+# Uses cutlass_mla as the decode backend for impl construction
+# (only the prefill path is exercised).
+#
+# Backends that aren't available on the current platform will report errors
+# in the results table (e.g., fa3 on Blackwell, cudnn without artifactory).
+#
+# Usage:
+#   python benchmark.py --config configs/mla_prefill.yaml
+
+description: "MLA prefill backend comparison"
 
 model:
   name: "deepseek-v3"
@@ -12,20 +27,25 @@ model:
   v_head_dim: 128
   block_size: 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"
+# model:
+#   name: "deepseek-v2-lite"
+#   num_layers: 27
+#   num_q_heads: 16
+#   num_kv_heads: 1
+#   head_dim: 576
+#   kv_lora_rank: 512
+#   qk_nope_head_dim: 128
+#   qk_rope_head_dim: 64
+#   v_head_dim: 128
+#   block_size: 128
 
 batch_specs:
   # Pure prefill
-  - "1q512"
-  - "1q1k"
-  - "1q2k"
-  - "1q4k"
-  - "1q8k"
+  - "q512"
+  - "q1k"
+  - "q2k"
+  - "q4k"
+  - "q8k"
 
   # Batched pure prefill
   - "2q512"
@@ -44,19 +64,63 @@ batch_specs:
   - "8q4k"
   - "8q8k"
 
-  # Extend
-  - "1q512s4k"
-  - "1q512s8k"
-  - "1q1ks8k"
-  - "1q2ks8k"
-  - "1q2ks16k"
-  - "1q4ks16k"
+  # Chunked prefill / extend
+  # Short context
+  - "q128s1k"
+  - "q256s2k"
+  - "q512s4k"
+  - "q1ks4k"
+  - "q2ks8k"
+  - "2q128s1k"
+  - "2q256s2k"
+  - "2q512s4k"
+  - "2q1ks4k"
+  - "2q2ks8k"
+  - "4q128s1k"
+  - "4q256s2k"
+  - "4q512s4k"
+  - "4q1ks4k"
+  - "4q2ks8k"
+  - "8q128s1k"
+  - "8q256s2k"
+  - "8q512s4k"
+  - "8q1ks4k"
+
+  # Medium context
+  - "q128s16k"
+  - "q512s16k"
+  - "q1ks16k"
+  - "q2ks16k"
+  - "2q128s16k"
+  - "2q512s16k"
+  - "2q1ks16k"
+  - "2q2ks16k"
+  - "4q128s16k"
+  - "4q512s16k"
+  - "4q1ks16k"
+  - "4q2ks16k"
+
+  # Long context
+  - "q128s64k"
+  - "q512s64k"
+  - "q1ks64k"
+  - "q2ks64k"
+  - "2q128s64k"
+  - "2q512s64k"
+  - "2q1ks64k"
+  - "2q2ks64k"
+
+decode_backends:
+  - CUTLASS_MLA
 
-backends:
-  - FLASHMLA_SPARSE
-  - FLASHINFER_MLA_SPARSE
+prefill_backends:
+  - fa2
+  - fa3
+  - fa4
+  - flashinfer
+  - cudnn
+  - trtllm
 
 device: "cuda:0"
-repeats: 10
-warmup_iters: 3
-profile_memory: true
+repeats: 20
+warmup_iters: 5