Add vLLM v0.18.1 source tree with KV transfer abort fix

third_party/vllm/ now tracked in git for direct patch management.
Based on vLLM v0.18.1 release with one patch applied:

  vllm/v1/core/sched/scheduler.py:
    Replace fatal assert with graceful skip when KV transfer callback
    arrives for an already-aborted request during PD disaggregated serving.

Future vLLM modifications should be made directly in third_party/vllm/
and committed normally. The patches/ directory is kept as documentation
of what changed from upstream.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

third_party/vllm/benchmarks/kernels/benchmark_rope.py

@@ -0,0 +1,108 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import itertools
+
+import torch
+
+from vllm.benchmarks.lib.utils import default_vllm_config
+from vllm.model_executor.layers.rotary_embedding import get_rope
+from vllm.triton_utils import triton
+from vllm.utils.argparse_utils import FlexibleArgumentParser
+
+batch_size_range = [2**i for i in range(0, 8, 2)]
+seq_len_range = [2**i for i in range(6, 10, 1)]
+num_heads_range = [32, 48]
+configs = list(itertools.product(batch_size_range, seq_len_range, num_heads_range))
+
+
+def get_benchmark(head_size, rotary_dim, is_neox_style, device):
+    @triton.testing.perf_report(
+        triton.testing.Benchmark(
+            x_names=["batch_size", "seq_len", "num_heads"],
+            x_vals=[list(_) for _ in configs],
+            line_arg="provider",
+            line_vals=["torch", "flashinfer", "vllm"],
+            line_names=["PyTorch", "FlashInfer", "vLLM"],
+            styles=[("blue", "-"), ("green", "-"), ("red", "-")],
+            ylabel="us",
+            plot_name=f"rope-perf{'-neox-style' if is_neox_style else ''}",
+            args={},
+        )
+    )
+    @default_vllm_config()
+    def benchmark(batch_size, seq_len, num_heads, provider):
+        dtype = torch.bfloat16
+        max_position = 8192
+        rope_parameters = {"partial_rotary_factor": rotary_dim / head_size}
+        rope = get_rope(head_size, max_position, is_neox_style, rope_parameters)
+        rope = rope.to(dtype=dtype, device=device)
+        cos_sin_cache = rope.cos_sin_cache.to(dtype=torch.float, device=device)
+
+        positions = torch.randint(0, max_position, (batch_size, seq_len), device=device)
+        query = torch.randn(
+            (batch_size, seq_len, num_heads * head_size), dtype=dtype, device=device
+        )
+        key = torch.randn_like(query)
+
+        quantiles = [0.5, 0.2, 0.8]
+
+        if provider == "torch":
+            ms, min_ms, max_ms = triton.testing.do_bench(
+                lambda: rope.forward_native(positions, query.clone(), key.clone()),
+                quantiles=quantiles,
+            )
+        elif provider == "flashinfer":
+            ms, min_ms, max_ms = triton.testing.do_bench(
+                lambda: torch.ops.vllm.flashinfer_rotary_embedding(
+                    positions,
+                    query.clone(),
+                    key.clone(),
+                    head_size,
+                    cos_sin_cache,
+                    is_neox_style,
+                ),
+                quantiles=quantiles,
+            )
+        else:
+            ms, min_ms, max_ms = triton.testing.do_bench(
+                lambda: rope.forward_cuda(positions, query.clone(), key.clone()),
+                quantiles=quantiles,
+            )
+
+        return 1000 * ms, 1000 * max_ms, 1000 * min_ms
+
+    return benchmark
+
+
+if __name__ == "__main__":
+    parser = FlexibleArgumentParser(
+        description="Benchmark the rotary embedding kernels."
+    )
+    parser.add_argument("--is-neox-style", type=bool, default=True)
+    parser.add_argument("--batch-size", type=int, default=16)
+    parser.add_argument("--seq-len", type=int, default=512)
+    parser.add_argument("--num-heads", type=int, default=8)
+    parser.add_argument(
+        "--head-size",
+        type=int,
+        choices=[64, 80, 96, 112, 120, 128, 192, 256],
+        default=128,
+    )
+    parser.add_argument("--rotary-dim", type=int, choices=[16, 32], default=32)
+    parser.add_argument(
+        "--dtype", type=str, choices=["bfloat16", "float"], default="float"
+    )
+    parser.add_argument("--seed", type=int, default=0)
+    parser.add_argument(
+        "--device", type=str, choices=["cuda:0", "cuda:1"], default="cuda:0"
+    )
+    parser.add_argument("--save-path", type=str, default="./configs/rope/")
+    args = parser.parse_args()
+
+    # Get the benchmark function
+    benchmark = get_benchmark(
+        args.head_size, args.rotary_dim, args.is_neox_style, args.device
+    )
+    # Run performance benchmark
+    benchmark.run(print_data=True, save_path=args.save_path)