Feature/silu block quant fusion v1 (#32996)

Signed-off-by: Monishver Chandrasekaran <monishverchandrasekaran@gmail.com>

benchmarks/fused_kernels/silu_mul_block_quant_benchmark.py

@@ -0,0 +1,211 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from collections.abc import Callable, Iterable
+from dataclasses import dataclass
+from itertools import product
+
+import torch
+import torch.nn.functional as F
+import torch.utils.benchmark as TBenchmark
+from torch.utils.benchmark import Measurement as TMeasurement
+from tqdm import tqdm
+
+import vllm._custom_ops as ops
+from vllm.model_executor.layers.quantization.utils.fp8_utils import (
+    per_token_group_quant_fp8,
+)
+
+
+@dataclass
+class bench_params_t:
+    num_tokens: int
+    hidden_size: int
+    dtype: torch.dtype
+    group_size: int  # Changed from list[int] to int
+
+    def description(self):
+        return (
+            f"N {self.num_tokens} "
+            f"x D {self.hidden_size} "
+            f"x DT {self.dtype} "
+            f"x GS {self.group_size}"
+        )
+
+
+def get_bench_params() -> list[bench_params_t]:
+    """Test configurations covering common model sizes."""
+    NUM_TOKENS = [16, 128, 512, 2048]
+    HIDDEN_SIZES = [1024, 2048, 4096, 5120, 14336]  # Common FFN sizes
+    DTYPES = [torch.float16, torch.bfloat16]
+    GROUP_SIZES = [64, 128]  # Changed from [[1, 64], [1, 128]]
+
+    combinations = product(NUM_TOKENS, HIDDEN_SIZES, DTYPES, GROUP_SIZES)
+    bench_params = list(
+        map(lambda x: bench_params_t(x[0], x[1], x[2], x[3]), combinations)
+    )
+    return bench_params
+
+
+# Reference implementations
+def unfused_fp8_impl(
+    x: torch.Tensor,
+    quant_dtype: torch.dtype,
+    group_size: int,  # Changed from list[int]
+):
+    """Unfused: SiLU+Mul then per-tensor quantize."""
+    hidden = x.shape[-1] // 2
+    gate, up = x.split(hidden, dim=-1)
+
+    # SiLU(gate) * up
+    silu_out = F.silu(gate) * up
+
+    # Per-tensor quantize (no group_size used here)
+    silu_out, _ = ops.scaled_fp8_quant(silu_out)
+
+
+def unfused_groupwise_fp8_impl(
+    x: torch.Tensor,
+    quant_dtype: torch.dtype,
+    group_size: int,  # Changed from list[int]
+):
+    """Unfused: SiLU+Mul then group-wise quantize."""
+    hidden = x.shape[-1] // 2
+    gate, up = x.split(hidden, dim=-1)
+
+    # SiLU(gate) * up
+    silu_out = F.silu(gate) * up
+
+    # Group quantize - use group_size directly
+    silu_out, _ = per_token_group_quant_fp8(
+        silu_out, group_size=group_size, use_ue8m0=False
+    )
+
+
+def fused_impl(
+    x: torch.Tensor,
+    quant_dtype: torch.dtype,
+    group_size: int,
+):
+    """Fused: SiLU+Mul+Block Quantization in single kernel."""
+    out, _ = ops.silu_and_mul_per_block_quant(
+        x,
+        group_size=group_size,
+        quant_dtype=quant_dtype,
+        is_scale_transposed=False,
+    )
+
+
+# Bench functions
+def bench_fn(
+    x: torch.Tensor,
+    quant_dtype: torch.dtype,
+    group_size: int,
+    label: str,
+    sub_label: str,
+    fn: Callable,
+    description: str,
+) -> TMeasurement:
+    min_run_time = 1
+
+    globals = {
+        "x": x,
+        "quant_dtype": quant_dtype,
+        "group_size": group_size,
+        "fn": fn,
+    }
+    return TBenchmark.Timer(
+        stmt="fn(x, quant_dtype, group_size)",
+        globals=globals,
+        label=label,
+        sub_label=sub_label,
+        description=description,
+    ).blocked_autorange(min_run_time=min_run_time)
+
+
+def bench(params: bench_params_t, label: str, sub_label: str) -> Iterable[TMeasurement]:
+    """Run benchmarks for all implementations."""
+    # Make inputs: [num_tokens, hidden_size * 2] for [gate || up]
+    scale = 1 / params.hidden_size
+    x = (
+        torch.randn(
+            params.num_tokens,
+            params.hidden_size * 2,
+            dtype=params.dtype,
+            device="cuda",
+        )
+        * scale
+    )
+
+    timers = []
+
+    # Unfused per-tensor FP8
+    timers.append(
+        bench_fn(
+            x,
+            torch.float8_e4m3fn,
+            params.group_size,
+            label,
+            sub_label,
+            unfused_fp8_impl,
+            "unfused_fp8_impl",
+        )
+    )
+
+    # Unfused group-wise FP8
+    timers.append(
+        bench_fn(
+            x,
+            torch.float8_e4m3fn,
+            params.group_size,
+            label,
+            sub_label,
+            unfused_groupwise_fp8_impl,
+            "unfused_groupwise_fp8_impl",
+        )
+    )
+
+    # Fused group-wise FP8
+    timers.append(
+        bench_fn(
+            x,
+            torch.float8_e4m3fn,
+            params.group_size,
+            label,
+            sub_label,
+            fused_impl,
+            "fused_groupwise_fp8_impl",
+        )
+    )
+
+    return timers
+
+
+def print_timers(timers: Iterable[TMeasurement]):
+    compare = TBenchmark.Compare(timers)
+    compare.print()
+
+
+def main():
+    torch.set_default_device("cuda")
+    bench_params = get_bench_params()
+
+    print(f"Running {len(bench_params)} benchmark configurations...")
+    print(
+        f"This will take approximately {len(bench_params) * 3} seconds (1s per variant)"
+    )
+    print()
+
+    timers = []
+    for bp in tqdm(bench_params):
+        result_timers = bench(bp, "silu-mul-block-quant", bp.description())
+        timers.extend(result_timers)
+
+    print("\n" + "=" * 80)
+    print("FINAL COMPARISON - ALL RESULTS")
+    print("=" * 80)
+    print_timers(timers)
+
+
+if __name__ == "__main__":
+    main()