[Model] New model support for Motif-1-Tiny (#23414)

Signed-off-by: ca1207 <ca1207zzz@gmail.com>
Signed-off-by: TaehyunKim <73943231+ca1207@users.noreply.github.com>
Co-authored-by: WyldeCat <skan1543@gmail.com>
Co-authored-by: Jee Jee Li <pandaleefree@gmail.com>

benchmarks/kernels/benchmark_polynorm.py

@@ -0,0 +1,155 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import itertools
+
+import torch
+
+from vllm import _custom_ops as vllm_ops
+from vllm.triton_utils import triton
+
+
+def polynorm_naive(
+    x: torch.Tensor,
+    weight: torch.Tensor,
+    bias: torch.Tensor,
+    eps: float = 1e-6,
+):
+    orig_shape = x.shape
+    x = x.view(-1, x.shape[-1])
+
+    def norm(x, eps: float):
+        return x / torch.sqrt(x.pow(2).mean(-1, keepdim=True) + eps)
+
+    x = x.float()
+    return (
+        (
+            weight[0] * norm(x**3, eps)
+            + weight[1] * norm(x**2, eps)
+            + weight[2] * norm(x, eps)
+            + bias
+        )
+        .to(weight.dtype)
+        .view(orig_shape)
+    )
+
+
+def polynorm_vllm(
+    x: torch.Tensor,
+    weight: torch.Tensor,
+    bias: torch.Tensor,
+    eps: float = 1e-6,
+):
+    orig_shape = x.shape
+    x = x.view(-1, x.shape[-1])
+
+    out = torch.empty_like(x)
+    vllm_ops.poly_norm(out, x, weight, bias, eps)
+    output = out
+
+    output = output.view(orig_shape)
+    return output
+
+
+def calculate_diff(batch_size, seq_len, hidden_dim):
+    dtype = torch.bfloat16
+    x = torch.randn(batch_size, seq_len, hidden_dim, dtype=dtype, device="cuda")
+    weight = torch.ones(3, dtype=dtype, device="cuda")
+    bias = torch.ones(1, dtype=dtype, device="cuda")
+
+    output_naive = polynorm_naive(x, weight, bias)
+    output_vllm = polynorm_vllm(x, weight, bias)
+
+    if torch.allclose(output_naive, output_vllm, atol=1e-2, rtol=1e-2):
+        print("✅ All implementations match")
+    else:
+        print("❌ Implementations differ")
+
+
+batch_size_range = [2**i for i in range(0, 7, 2)]
+seq_length_range = [2**i for i in range(6, 11, 1)]
+dim_range = [2048, 4096]
+configs = list(itertools.product(dim_range, batch_size_range, seq_length_range))
+
+
+def get_benchmark():
+    @triton.testing.perf_report(
+        triton.testing.Benchmark(
+            x_names=["dim", "batch_size", "seq_len"],
+            x_vals=[list(_) for _ in configs],
+            line_arg="provider",
+            line_vals=["naive", "vllm"],
+            line_names=["Naive", "vLLM"],
+            styles=[("blue", "-"), ("red", "-")],
+            ylabel="us",
+            plot_name="polynorm-perf",
+            args={},
+        )
+    )
+    def benchmark(dim, batch_size, seq_len, provider):
+        dtype = torch.bfloat16
+        hidden_dim = dim * 4
+
+        x = torch.randn(batch_size, seq_len, hidden_dim, dtype=dtype, device="cuda")
+        weight = torch.ones(3, dtype=dtype, device="cuda")
+        bias = torch.ones(1, dtype=dtype, device="cuda")
+
+        quantiles = [0.5, 0.2, 0.8]
+
+        if provider == "naive":
+            ms, min_ms, max_ms = triton.testing.do_bench(
+                lambda: polynorm_naive(x, weight, bias),
+                quantiles=quantiles,
+            )
+        else:
+            ms, min_ms, max_ms = triton.testing.do_bench(
+                lambda: polynorm_vllm(x, weight, bias),
+                quantiles=quantiles,
+            )
+
+        return 1000 * ms, 1000 * max_ms, 1000 * min_ms
+
+    return benchmark
+
+
+if __name__ == "__main__":
+    import argparse
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--batch-size",
+        type=int,
+        default=4,
+        help="Batch size",
+    )
+    parser.add_argument(
+        "--seq-len",
+        type=int,
+        default=128,
+        help="Sequence length",
+    )
+    parser.add_argument(
+        "--hidden-dim",
+        type=int,
+        default=8192,
+        help="Intermediate size of MLP",
+    )
+    parser.add_argument(
+        "--save-path",
+        type=str,
+        default="./configs/polnorm/",
+        help="Path to save polnorm benchmark results",
+    )
+
+    args = parser.parse_args()
+
+    # Run correctness test
+    calculate_diff(
+        batch_size=args.batch_size,
+        seq_len=args.seq_len,
+        hidden_dim=args.hidden_dim,
+    )
+
+    benchmark = get_benchmark()
+    # Run performance benchmark
+    benchmark.run(print_data=True, save_path=args.save_path)

csrc/layernorm_kernels.cu

@@ -140,6 +140,211 @@ fused_add_rms_norm_kernel(
   }
 }
 
+/* Function specialization in the case of FP16/BF16 tensors.
+   Additional optimizations we can make in this case are
+   packed and vectorized operations, which help with the
+   memory latency bottleneck.
+
+   _f16VecPN struct extends _f16Vec to add operations specifically required for
+   polynomial normalization (poly norm).
+   The original _f16Vec does not include the sum-of-powers computation or
+   in-place polynomial normalization logic. */
+template <typename scalar_t, int width>
+struct alignas(16) _f16VecPN : _f16Vec<scalar_t, width> {
+  using Base = _f16Vec<scalar_t, width>;
+  using Converter = typename Base::Converter;
+  using T1 = typename Base::T1;
+  using T2 = typename Base::T2;
+  using Base::data;
+
+  __device__ auto sum_pows() const {
+    float s2 = 0.0f, s4 = 0.0f, s6 = 0.0f;
+
+#pragma unroll
+    for (int i = 0; i < width; i += 2) {
+      float2 z = Converter::convert(T2{data[i], data[i + 1]});
+      float x2 = z.x * z.x;
+      float x4 = x2 * x2;
+      float x6 = x4 * x2;
+
+      float y2 = z.y * z.y;
+      float y4 = y2 * y2;
+      float y6 = y4 * y2;
+
+      s2 += x2 + y2;
+      s4 += x4 + y4;
+      s6 += x6 + y6;
+    }
+    return std::make_tuple(s2, s4, s6);
+  }
+
+  __device__ void poly_norm_inplace(const float w2_inv_std,
+                                    const float w1_inv_std2,
+                                    const float w0_inv_std3, const float bias) {
+#pragma unroll
+    for (int i = 0; i < width; i += 2) {
+      float2 z = Converter::convert(T2{data[i], data[i + 1]});
+
+      float x2 = z.x * z.x;
+      float x3 = x2 * z.x;
+      z.x = w2_inv_std * z.x + w1_inv_std2 * x2 + w0_inv_std3 * x3 + bias;
+
+      float y2 = z.y * z.y;
+      float y3 = y2 * z.y;
+      z.y = w2_inv_std * z.y + w1_inv_std2 * y2 + w0_inv_std3 * y3 + bias;
+
+      auto out = Converter::convert(z);
+      data[i] = out.x;
+      data[i + 1] = out.y;
+    }
+  }
+};
+
+template <typename scalar_t, int width>
+__global__ std::enable_if_t<(width > 0) && _typeConvert<scalar_t>::exists>
+poly_norm_kernel(scalar_t* __restrict__ out,           // [..., hidden_size]
+                 const scalar_t* __restrict__ input,   // [..., hidden_size]
+                 const scalar_t* __restrict__ weight,  // [3]
+                 const scalar_t* __restrict__ bias,    // [1]
+                 const float epsilon, const int hidden_size) {
+  // Sanity checks on our vector struct and type-punned pointer arithmetic
+  static_assert(std::is_pod_v<_f16VecPN<scalar_t, width>>);
+  static_assert(sizeof(_f16VecPN<scalar_t, width>) == sizeof(scalar_t) * width);
+
+  /* These and the argument pointers are all declared `restrict` as they are
+     not aliased in practice. Argument pointers should not be dereferenced
+     in this kernel as that would be undefined behavior */
+  auto* __restrict__ input_v =
+      reinterpret_cast<const _f16VecPN<scalar_t, width>*>(input);
+  const int vec_hidden_size = hidden_size / width;
+  float variance = 0.0f;
+  float variance2 = 0.0f;
+  float variance3 = 0.0f;
+
+  for (int idx = threadIdx.x; idx < vec_hidden_size; idx += blockDim.x) {
+    int id = blockIdx.x * vec_hidden_size + idx;
+    _f16VecPN<scalar_t, width> temp = input_v[id];
+    auto [x2, x4, x6] = temp.sum_pows();
+
+    variance += x2;
+    variance2 += x4;
+    variance3 += x6;
+  }
+
+  float3 thread_variances = make_float3(variance, variance2, variance3);
+
+  struct SumOp {
+    __device__ float3 operator()(const float3& a, const float3& b) const {
+      return make_float3(a.x + b.x, a.y + b.y, a.z + b.z);
+    }
+  };
+
+  using BlockReduce = cub::BlockReduce<float3, 1024>;
+  __shared__ typename BlockReduce::TempStorage reduceStore;
+  float3 block_variances =
+      BlockReduce(reduceStore).Reduce(thread_variances, SumOp{}, blockDim.x);
+
+  variance = block_variances.x;
+  variance2 = block_variances.y;
+  variance3 = block_variances.z;
+
+  __shared__ float s_w2_inv_std;
+  __shared__ float s_w1_inv_std2;
+  __shared__ float s_w0_inv_std3;
+  __shared__ float s_bias;
+
+  if (threadIdx.x == 0) {
+    float w0 = (float)weight[0];
+    float w1 = (float)weight[1];
+    float w2 = (float)weight[2];
+    s_bias = (float)bias[0];
+
+    s_w2_inv_std = w2 * rsqrtf(variance / hidden_size + epsilon);
+    s_w1_inv_std2 = w1 * rsqrtf(variance2 / hidden_size + epsilon);
+    s_w0_inv_std3 = w0 * rsqrtf(variance3 / hidden_size + epsilon);
+  }
+  __syncthreads();
+
+  auto* __restrict__ out_v = reinterpret_cast<_f16VecPN<scalar_t, width>*>(out);
+
+  for (int idx = threadIdx.x; idx < vec_hidden_size; idx += blockDim.x) {
+    int id = blockIdx.x * vec_hidden_size + idx;
+    _f16VecPN<scalar_t, width> temp = input_v[id];
+    temp.poly_norm_inplace(s_w2_inv_std, s_w1_inv_std2, s_w0_inv_std3, s_bias);
+    out_v[id] = temp;
+  }
+}
+
+/* Generic poly_norm_kernel
+   The width field is not used here but necessary for other specializations.
+ */
+template <typename scalar_t, int width>
+__global__ std::enable_if_t<(width == 0) || !_typeConvert<scalar_t>::exists>
+poly_norm_kernel(scalar_t* __restrict__ out,           // [..., hidden_size]
+                 const scalar_t* __restrict__ input,   // [..., hidden_size]
+                 const scalar_t* __restrict__ weight,  // [3]
+                 const scalar_t* __restrict__ bias,    // [1]
+                 const float epsilon, const int hidden_size) {
+  float variance = 0.0f;
+  float variance2 = 0.0f;
+  float variance3 = 0.0f;
+
+  for (int idx = threadIdx.x; idx < hidden_size; idx += blockDim.x) {
+    float x = (float)input[blockIdx.x * hidden_size + idx];
+    float x2 = x * x;
+    float x4 = x2 * x2;
+    float x6 = x4 * x2;
+
+    variance += x2;
+    variance2 += x4;
+    variance3 += x6;
+  }
+
+  float3 thread_variances = make_float3(variance, variance2, variance3);
+
+  struct SumOp {
+    __device__ float3 operator()(const float3& a, const float3& b) const {
+      return make_float3(a.x + b.x, a.y + b.y, a.z + b.z);
+    }
+  };
+
+  using BlockReduce = cub::BlockReduce<float3, 1024>;
+  __shared__ typename BlockReduce::TempStorage reduceStore;
+  float3 block_variances =
+      BlockReduce(reduceStore).Reduce(thread_variances, SumOp{}, blockDim.x);
+
+  variance = block_variances.x;
+  variance2 = block_variances.y;
+  variance3 = block_variances.z;
+
+  __shared__ float s_w2_inv_std;
+  __shared__ float s_w1_inv_std2;
+  __shared__ float s_w0_inv_std3;
+  __shared__ float s_bias;
+
+  if (threadIdx.x == 0) {
+    float w0 = (float)weight[0];
+    float w1 = (float)weight[1];
+    float w2 = (float)weight[2];
+    s_bias = (float)bias[0];
+
+    s_w2_inv_std = w2 * rsqrtf(variance / hidden_size + epsilon);
+    s_w1_inv_std2 = w1 * rsqrtf(variance2 / hidden_size + epsilon);
+    s_w0_inv_std3 = w0 * rsqrtf(variance3 / hidden_size + epsilon);
+  }
+  __syncthreads();
+
+  for (int idx = threadIdx.x; idx < hidden_size; idx += blockDim.x) {
+    float x = (float)input[blockIdx.x * hidden_size + idx];
+    float x2 = x * x;
+    float x3 = x2 * x;
+
+    out[blockIdx.x * hidden_size + idx] =
+        (scalar_t)(x * s_w2_inv_std + x2 * s_w1_inv_std2 + x3 * s_w0_inv_std3 +
+                   s_bias);
+  }
+}
+
 }  // namespace vllm
 
 void rms_norm(torch::Tensor& out,     // [..., hidden_size]
@@ -219,3 +424,49 @@ void fused_add_rms_norm(torch::Tensor& input,     // [..., hidden_size]
     LAUNCH_FUSED_ADD_RMS_NORM(0);
   }
 }
+
+#define LAUNCH_FUSED_POLY_NORM(width)                                         \
+  VLLM_DISPATCH_FLOATING_TYPES(input.scalar_type(), "poly_norm_kernel", [&] { \
+    vllm::poly_norm_kernel<scalar_t, width><<<grid, block, 0, stream>>>(      \
+        out.data_ptr<scalar_t>(), input.data_ptr<scalar_t>(),                 \
+        weight.data_ptr<scalar_t>(), bias.data_ptr<scalar_t>(), epsilon,      \
+        hidden_size);                                                         \
+  });
+
+void poly_norm(torch::Tensor& out,     // [..., hidden_size]
+               torch::Tensor& input,   // [..., hidden_size]
+               torch::Tensor& weight,  // [3]
+               torch::Tensor& bias,    // [1]
+               double epsilon) {
+  TORCH_CHECK(out.is_contiguous());
+  TORCH_CHECK(input.is_contiguous());
+  TORCH_CHECK(out.data_ptr() != input.data_ptr());
+
+  int hidden_size = input.size(-1);
+  int num_tokens = input.numel() / hidden_size;
+
+  dim3 grid(num_tokens);
+  /* This kernel is memory-latency bound in many scenarios.
+     When num_tokens is large, a smaller block size allows
+     for increased block occupancy on CUs and better latency
+     hiding on global mem ops. */
+  const int max_block_size = (num_tokens < 256) ? 1024 : 256;
+  dim3 block(std::min(hidden_size, max_block_size));
+  const at::cuda::OptionalCUDAGuard device_guard(device_of(input));
+  const cudaStream_t stream = at::cuda::getCurrentCUDAStream();
+  /*If the tensor types are FP16/BF16, try to use the optimized kernel
+    with packed + vectorized ops.
+    Max optimization is achieved with a width-8 vector of FP16/BF16s
+    since we can load at most 128 bits at once in a global memory op.
+    However, this requires each tensor's data to be aligned to 16
+    bytes.
+   */
+  auto inp_ptr = reinterpret_cast<std::uintptr_t>(input.data_ptr());
+  auto out_ptr = reinterpret_cast<std::uintptr_t>(out.data_ptr());
+  bool ptrs_are_aligned = inp_ptr % 16 == 0 && out_ptr % 16 == 0;
+  if (ptrs_are_aligned && hidden_size % 8 == 0) {
+    LAUNCH_FUSED_POLY_NORM(8);
+  } else {
+    LAUNCH_FUSED_POLY_NORM(0);
+  }
+}

csrc/ops.h

@@ -92,6 +92,9 @@ void rms_norm(torch::Tensor& out, torch::Tensor& input, torch::Tensor& weight,
 void fused_add_rms_norm(torch::Tensor& input, torch::Tensor& residual,
                         torch::Tensor& weight, double epsilon);
 
+void poly_norm(torch::Tensor& out, torch::Tensor& input, torch::Tensor& weight,
+               torch::Tensor& bias, double epsilon);
+
 void apply_repetition_penalties_(torch::Tensor& logits,
                                  const torch::Tensor& prompt_mask,
                                  const torch::Tensor& output_mask,
@@ -353,4 +356,4 @@ void qr_open_handles(fptr_t _fa, const std::vector<torch::Tensor>& handles);
 void qr_all_reduce(fptr_t _fa, torch::Tensor& inp, torch::Tensor& out,
                    int64_t quant_level, bool cast_bf2half = false);
 int64_t qr_max_size();
-#endif
+#endif

csrc/torch_bindings.cpp

@@ -168,6 +168,12 @@ TORCH_LIBRARY_EXPAND(TORCH_EXTENSION_NAME, ops) {
       "float epsilon) -> ()");
   ops.impl("fused_add_rms_norm", torch::kCUDA, &fused_add_rms_norm);
 
+  // Polynomial Normalization.
+  ops.def(
+      "poly_norm(Tensor! out, Tensor input, Tensor weight, Tensor bias, float "
+      "epsilon) -> ()");
+  ops.impl("poly_norm", torch::kCUDA, &poly_norm);
+
   // Apply repetition penalties to logits in-place
   ops.def(
       "apply_repetition_penalties_(Tensor! logits, Tensor prompt_mask, "

docs/models/supported_models.md

@@ -383,6 +383,7 @@ th {
 | `MiniCPM3ForCausalLM` | MiniCPM3 | `openbmb/MiniCPM3-4B`, etc. | ✅︎ | ✅︎ | ✅︎ |
 | `MistralForCausalLM` | Mistral, Mistral-Instruct | `mistralai/Mistral-7B-v0.1`, `mistralai/Mistral-7B-Instruct-v0.1`, etc. | ✅︎ | ✅︎ | ✅︎ |
 | `MixtralForCausalLM` | Mixtral-8x7B, Mixtral-8x7B-Instruct | `mistralai/Mixtral-8x7B-v0.1`, `mistralai/Mixtral-8x7B-Instruct-v0.1`, `mistral-community/Mixtral-8x22B-v0.1`, etc. | ✅︎ | ✅︎ | ✅︎ |
+| `MotifForCausalLM` | Motif-1-Tiny | `Motif-Technologies/Motif-2.6B`, `Motif-Technologies/Motif-2.6b-v1.1-LC`, etc. | ✅︎ | ✅︎ | |
 | `MPTForCausalLM` | MPT, MPT-Instruct, MPT-Chat, MPT-StoryWriter | `mosaicml/mpt-7b`, `mosaicml/mpt-7b-storywriter`, `mosaicml/mpt-30b`, etc. | | ✅︎ | ✅︎ |
 | `NemotronForCausalLM` | Nemotron-3, Nemotron-4, Minitron | `nvidia/Minitron-8B-Base`, `mgoin/Nemotron-4-340B-Base-hf-FP8`, etc. | ✅︎ | ✅︎ | ✅︎ |
 | `NemotronHForCausalLM` | Nemotron-H | `nvidia/Nemotron-H-8B-Base-8K`, `nvidia/Nemotron-H-47B-Base-8K`, `nvidia/Nemotron-H-56B-Base-8K`, etc. | ✅︎ | ✅︎ | ✅︎ |

tests/kernels/core/test_layernorm.py

@@ -6,7 +6,7 @@ import torch
 
 from tests.kernels.quant_utils import FP8_DTYPE
 from tests.kernels.utils import opcheck
-from vllm.model_executor.layers.layernorm import RMSNorm
+from vllm.model_executor.layers.layernorm import PolyNorm, RMSNorm
 from vllm.platforms import current_platform
 
 DTYPES = [torch.half, torch.bfloat16, torch.float]
@@ -70,6 +70,37 @@ def test_rms_norm(
                 (out, x, layer.weight.data, layer.variance_epsilon))
 
 
+@pytest.mark.parametrize("num_tokens", NUM_TOKENS)
+@pytest.mark.parametrize("hidden_size", HIDDEN_SIZES)
+@pytest.mark.parametrize("dtype", DTYPES)
+@pytest.mark.parametrize("seed", SEEDS)
+@pytest.mark.parametrize("device", CUDA_DEVICES)
+@torch.inference_mode()
+def test_poly_norm(
+    num_tokens: int,
+    hidden_size: int,
+    dtype: torch.dtype,
+    seed: int,
+    device: str,
+) -> None:
+    current_platform.seed_everything(seed)
+    torch.set_default_device(device)
+    layer = PolyNorm().to(dtype=dtype)
+    layer.weight.data.normal_(mean=1.0, std=0.1)
+    layer.bias.data.normal_(mean=1.0, std=0.1)
+    scale = 1 / (2 * hidden_size)
+    x = torch.randn(num_tokens, hidden_size, dtype=dtype)
+    x *= scale
+
+    ref_out = layer.forward_native(x)
+    out = layer(x)
+    torch.testing.assert_close(out, ref_out, atol=1e-2, rtol=1e-2)
+
+    opcheck(
+        torch.ops._C.poly_norm,
+        (out, x, layer.weight.data, layer.bias.data, layer.variance_epsilon))
+
+
 @pytest.mark.parametrize("num_tokens", NUM_TOKENS)
 @pytest.mark.parametrize("hidden_size", HIDDEN_SIZES)
 @pytest.mark.parametrize("add_residual", ADD_RESIDUAL)

tests/models/registry.py

@@ -291,6 +291,9 @@ _TEXT_GENERATION_EXAMPLE_MODELS = {
     "MistralForCausalLM": _HfExamplesInfo("mistralai/Mistral-7B-Instruct-v0.1"),
     "MixtralForCausalLM": _HfExamplesInfo("mistralai/Mixtral-8x7B-Instruct-v0.1",  # noqa: E501
                                           {"tiny": "TitanML/tiny-mixtral"}),  # noqa: E501
+    "MotifForCausalLM": _HfExamplesInfo("Motif-Technologies/Motif-2.6B",
+                                        trust_remote_code=True,
+                                        v0_only=True),
     "MptForCausalLM": _HfExamplesInfo("mpt", is_available_online=False),
     "MPTForCausalLM": _HfExamplesInfo("mosaicml/mpt-7b"),
     "NemotronForCausalLM": _HfExamplesInfo("nvidia/Minitron-8B-Base"),

tests/models/test_initialization.py

@@ -63,8 +63,9 @@ def can_initialize(model_arch: str, monkeypatch: pytest.MonkeyPatch,
                        _initialize_kv_caches_v1), monkeypatch.context() as m):
         if model_info.v0_only:
             m.setenv("VLLM_USE_V1", "0")
-        if model_arch == "Phi4FlashForCausalLM":
-            # Phi4FlashForCausalLM only supports DIFFERENTIAL_FLASH_ATTN backend
+        if model_arch in ("Phi4FlashForCausalLM", "MotifForCausalLM"):
+            # Phi4FlashForCausalLM and MotifForCausalLM
+            # only supports DIFFERENTIAL_FLASH_ATTN backend
             m.setenv("VLLM_ATTENTION_BACKEND", "DIFFERENTIAL_FLASH_ATTN")
         if model_arch == "GptOssForCausalLM":
             # FIXME: A hack to bypass FA3 assertion because our CI's L4 GPU

vllm/_custom_ops.py

@@ -280,6 +280,13 @@ def fused_add_rms_norm(input: torch.Tensor, residual: torch.Tensor,
     torch.ops._C.fused_add_rms_norm(input, residual, weight, epsilon)
 
 
+def poly_norm(out: torch.Tensor, input: torch.Tensor, weight: torch.Tensor,
+              bias: torch.Tensor, epsilon: float) -> None:
+    # TODO: Remove this contiguous call when the kernel is updated to support non-contiguous input
+    input_contiguous = input.contiguous()
+    torch.ops._C.poly_norm(out, input_contiguous, weight, bias, epsilon)
+
+
 def apply_repetition_penalties_torch(
         logits: torch.Tensor, prompt_mask: torch.Tensor,
         output_mask: torch.Tensor, repetition_penalties: torch.Tensor) -> None:
@@ -710,6 +717,7 @@ def cutlass_sparse_scaled_mm_supported(cuda_device_capability: int) -> bool:
 def cutlass_group_gemm_supported(cuda_device_capability: int) -> bool:
     return torch.ops._C.cutlass_group_gemm_supported(cuda_device_capability)
 
+
 def cutlass_sparse_compress(a: torch.Tensor) \
     -> tuple[torch.Tensor, torch.Tensor]:
     """

vllm/attention/backends/differential_flash_attn.py

@@ -734,6 +734,7 @@ class DifferentialFlashAttentionImpl(AttentionImpl):
                     window_size=self.sliding_window,
                     alibi_slopes=self.alibi_slopes,
                     softcap=self.logits_soft_cap,
+                    fa_version=self.vllm_flash_attn_version,
                 )
                 assert prefill_output.shape == output[:
                                                       num_prefill_tokens].shape
@@ -755,6 +756,7 @@ class DifferentialFlashAttentionImpl(AttentionImpl):
                     window_size=self.sliding_window,
                     alibi_slopes=self.alibi_slopes,
                     softcap=self.logits_soft_cap,
+                    fa_version=self.vllm_flash_attn_version,
                 ).squeeze(1)
             except Exception as e:
                 logger.error("Error in PagedAttention.forward_decode: %s",
@@ -787,6 +789,7 @@ class DifferentialFlashAttentionImpl(AttentionImpl):
             window_size=self.sliding_window,
             alibi_slopes=self.alibi_slopes,
             softcap=self.logits_soft_cap,
+            fa_version=self.vllm_flash_attn_version,
         ).squeeze(1)
         return output
 

vllm/model_executor/layers/layernorm.py

@@ -43,6 +43,20 @@ def fused_add_rms_norm(
     return x, residual
 
 
+def poly_norm(x: torch.Tensor, weight: torch.Tensor, bias: torch.Tensor,
+              variance_epsilon: float) -> torch.Tensor:
+    from vllm import _custom_ops as ops
+    out = torch.empty_like(x)
+    ops.poly_norm(
+        out,
+        x,
+        weight,
+        bias,
+        variance_epsilon,
+    )
+    return out
+
+
 def rocm_aiter_rms_norm_impl(x: torch.Tensor, weight: torch.Tensor,
                              variance_epsilon: float) -> torch.Tensor:
     import aiter as rocm_aiter
@@ -320,3 +334,48 @@ class GemmaRMSNorm(CustomOp):
                 self.forward_static)
             self._is_compiled = True
         return self.forward_native(x, residual)
+
+
+@CustomOp.register("poly_norm")
+class PolyNorm(CustomOp):
+    """Polynomial normalization.
+
+    Computes x -> w_0 * RMSNorm(x^3) + w_1 * RMSNorm(x^2) + w_2 * RMSNorm(x) + b
+    where w_n is the learned weight and b is the bias.
+    Refer to https://arxiv.org/html/2411.03884v1
+    """
+
+    def __init__(
+        self,
+        eps: float = 1e-6,
+    ) -> None:
+        super().__init__()
+        self.weight = torch.nn.Parameter(torch.ones(3) / 3)
+        self.bias = torch.nn.Parameter(torch.zeros(1))
+        self.variance_epsilon = eps
+
+    def _norm(self, x):
+        return x / torch.sqrt(
+            x.pow(2).mean(-1, keepdim=True) + self.variance_epsilon)
+
+    def forward_native(
+        self,
+        x: torch.Tensor,
+    ) -> torch.Tensor:
+        """PyTorch-native implementation equivalent to forward().
+
+        Refer to https://github.com/BryceZhuo/PolyCom?tab=readme-ov-file/README.md
+        """
+
+        orig_dtype = x.dtype
+        x_float = x.to(torch.float32)
+        output = (self.weight[0] * self._norm(x_float**3) +
+                  self.weight[1] * self._norm(x_float**2) +
+                  self.weight[2] * self._norm(x_float) + self.bias)
+        return output.to(orig_dtype)
+
+    def forward_cuda(
+        self,
+        x: torch.Tensor,
+    ) -> torch.Tensor:
+        return poly_norm(x, self.weight, self.bias, self.variance_epsilon)

vllm/model_executor/models/motif.py

@@ -0,0 +1,345 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+# Adapted from
+# https://huggingface.co/Motif-Technologies/Motif-2.6B/blob/main/modeling_motif.py
+# Copyright (c) Alibaba Cloud.
+# LICENSE: https://huggingface.co/Motif-Technologies/Motif-2.6B/blob/main/LICENSE
+"""Inference-only Motif model compatible with HuggingFace weights."""
+import math
+from typing import Any, Optional
+
+import torch
+from torch import nn
+from transformers import PretrainedConfig
+
+from vllm.attention import Attention, AttentionType
+from vllm.attention.selector import _Backend
+from vllm.config import CacheConfig, VllmConfig
+from vllm.distributed import get_tensor_model_parallel_world_size
+from vllm.model_executor.layers.layernorm import PolyNorm, RMSNorm
+from vllm.model_executor.layers.linear import (MergedColumnParallelLinear,
+                                               QKVParallelLinear,
+                                               RowParallelLinear)
+from vllm.model_executor.layers.quantization import QuantizationConfig
+from vllm.model_executor.layers.rotary_embedding import get_rope
+from vllm.model_executor.models.llama import LlamaForCausalLM
+
+from .adapters import as_seq_cls_model
+from .interfaces import SupportsV0Only
+from .utils import extract_layer_index
+
+
+class MotifMLP(nn.Module):
+    """MLP for the language component of the Motif model, which contains a
+    MergedColumnParallelLinear merging 2 outputs via PolyNorm activation."""
+
+    def __init__(
+        self,
+        hidden_size: int,
+        intermediate_size: int,
+        hidden_act: str = "poly_norm",
+        quant_config: Optional[QuantizationConfig] = None,
+        bias: bool = False,
+        prefix: str = "",
+        reduce_results: bool = True,
+    ):
+        super().__init__()
+        self.gate_up_proj = MergedColumnParallelLinear(
+            input_size=hidden_size,
+            output_sizes=[intermediate_size] * 2,
+            bias=bias,
+            quant_config=quant_config,
+            prefix=f"{prefix}.gate_up_proj",
+        )
+        self.down_proj = RowParallelLinear(
+            input_size=intermediate_size,
+            output_size=hidden_size,
+            bias=bias,
+            quant_config=quant_config,
+            reduce_results=reduce_results,
+            prefix=f"{prefix}.down_proj",
+        )
+        if hidden_act != "poly_norm":
+            raise NotImplementedError(f"Unsupported activation: {hidden_act}. "
+                                      "Only poly_norm is supported for now.")
+        self.act_fn = PolyNorm()
+        self.intermediate_size = intermediate_size
+        tp_size = get_tensor_model_parallel_world_size()
+        if hidden_act == "poly_norm" and tp_size > 1:
+            raise NotImplementedError(
+                "Tensor parallelism for poly_norm is not supported yet. "
+                "Support will be added in the future.")
+
+    def forward(self, x):
+        x, _ = self.gate_up_proj(x)
+        x = self.act_fn(
+            x[..., :self.intermediate_size]) * x[..., self.intermediate_size:]
+        x, _ = self.down_proj(x)
+        return x
+
+
+class MotifAttention(nn.Module):
+
+    def __init__(
+        self,
+        config: PretrainedConfig,
+        hidden_size: int,
+        num_heads: int,
+        num_kv_heads: int,
+        rope_theta: float = 10000,
+        rope_scaling: Optional[dict[str, Any]] = None,
+        max_position_embeddings: int = 8192,
+        quant_config: Optional[QuantizationConfig] = None,
+        bias: bool = False,
+        bias_o_proj: bool = False,
+        cache_config: Optional[CacheConfig] = None,
+        prefix: str = "",
+        attn_type: str = AttentionType.DECODER,
+    ) -> None:
+        super().__init__()
+        layer_idx = extract_layer_index(prefix)
+        self.hidden_size = hidden_size
+        tp_size = get_tensor_model_parallel_world_size()
+        self.total_num_heads = num_heads
+        assert self.total_num_heads % tp_size == 0
+        self.num_heads = self.total_num_heads // tp_size
+        self.total_num_kv_heads = num_kv_heads
+        if self.total_num_kv_heads >= tp_size:
+            # Number of KV heads is greater than TP size, so we partition
+            # the KV heads across multiple tensor parallel GPUs.
+            assert self.total_num_kv_heads % tp_size == 0
+        else:
+            # Number of KV heads is less than TP size, so we replicate
+            # the KV heads across multiple tensor parallel GPUs.
+            assert tp_size % self.total_num_kv_heads == 0
+        self.num_kv_heads = max(1, self.total_num_kv_heads // tp_size)
+        # MistralConfig has an optional head_dim introduced by Mistral-Nemo
+        head_dim = getattr(config, "head_dim", None)
+        if head_dim is None:
+            head_dim = self.hidden_size // self.total_num_heads
+        self.head_dim = head_dim
+        # Phi models introduced a partial_rotary_factor parameter in the config
+        self.partial_rotary_factor = getattr(config, "partial_rotary_factor",
+                                             1)
+        self.q_size = self.num_heads * self.head_dim
+        self.kv_size = self.num_kv_heads * self.head_dim
+        self.scaling = self.head_dim**-0.5
+        self.rope_theta = rope_theta
+        self.max_position_embeddings = max_position_embeddings
+
+        assert self.num_heads % 2 == 0, 'num_heads should be even'
+        assert self.num_kv_heads % 2 == 0, 'num_heads should be even'
+
+        self.qkv_proj = QKVParallelLinear(
+            hidden_size=hidden_size,
+            head_size=self.head_dim,
+            total_num_heads=self.total_num_heads,
+            total_num_kv_heads=self.total_num_kv_heads,
+            bias=bias,
+            quant_config=quant_config,
+            prefix=f"{prefix}.qkv_proj",
+        )
+
+        self.o_proj = RowParallelLinear(
+            input_size=self.total_num_heads * self.head_dim,
+            output_size=hidden_size,
+            bias=bias_o_proj,
+            quant_config=quant_config,
+            prefix=f"{prefix}.o_proj",
+        )
+
+        self._init_rotary_emb(config,
+                              rope_scaling=rope_scaling,
+                              quant_config=quant_config)
+        sliding_window = None
+
+        self.lambda_init = self.lambda_init_fn(layer_idx)
+        self.lambda_q1 = nn.Parameter(
+            torch.zeros(self.head_dim, dtype=torch.float32).normal_(mean=0,
+                                                                    std=0.1))
+        self.lambda_k1 = nn.Parameter(
+            torch.zeros(self.head_dim, dtype=torch.float32).normal_(mean=0,
+                                                                    std=0.1))
+        self.lambda_q2 = nn.Parameter(
+            torch.zeros(self.head_dim, dtype=torch.float32).normal_(mean=0,
+                                                                    std=0.1))
+        self.lambda_k2 = nn.Parameter(
+            torch.zeros(self.head_dim, dtype=torch.float32).normal_(mean=0,
+                                                                    std=0.1))
+        self.subln = RMSNorm(2 * self.head_dim, eps=config.attn_rms_norm_eps)
+
+        params = {
+            'differential_flash_attention_config': {
+                'lambda_init': self.lambda_init,
+                'lambda_q1': self.lambda_q1,
+                'lambda_k1': self.lambda_k1,
+                'lambda_q2': self.lambda_q2,
+                'lambda_k2': self.lambda_k2,
+                "subln": self.subln,
+            }
+        }
+
+        diff_attn_err_msg = (
+            'Set VLLM_ATTENTION_BACKEND="DIFFERENTIAL_FLASH_ATTN" '
+            'to enable Differential Flash Attention.')
+        try:
+            self.attn = Attention(
+                self.num_heads,
+                self.head_dim,
+                self.scaling,
+                num_kv_heads=self.num_kv_heads,
+                cache_config=cache_config,
+                quant_config=quant_config,
+                per_layer_sliding_window=sliding_window,
+                attn_type=attn_type,
+                prefix=f"{prefix}.attn",
+                **params,
+            )
+        except TypeError as e:
+            raise ValueError(diff_attn_err_msg) from e
+        assert (self.attn.backend == _Backend.DIFFERENTIAL_FLASH_ATTN
+                ), diff_attn_err_msg
+
+    def lambda_init_fn(self, depth):
+        return 0.8 - 0.6 * math.exp(-0.3 * (depth - 1))
+
+    def forward(
+        self,
+        positions: torch.Tensor,
+        hidden_states: torch.Tensor,
+    ) -> torch.Tensor:
+        qkv, _ = self.qkv_proj(hidden_states)
+        q, k, v = qkv.split([self.q_size, self.kv_size, self.kv_size], dim=-1)
+        q, k = self.rotary_emb(positions, q, k)
+        attn_output = self.attn(q, k, v)
+        output, _ = self.o_proj(attn_output)
+        return output
+
+    def _init_rotary_emb(self, config: PretrainedConfig,
+                         rope_scaling: Optional[dict[str, Any]],
+                         quant_config: Optional[QuantizationConfig]) -> None:
+        is_neox_style = True
+        is_gguf = quant_config and quant_config.get_name() == "gguf"
+        if is_gguf and config.model_type == "llama":
+            is_neox_style = False
+
+        self.rotary_emb = get_rope(
+            self.head_dim,
+            rotary_dim=self.head_dim,
+            max_position=self.max_position_embeddings,
+            base=self.rope_theta,
+            rope_scaling=rope_scaling,
+            is_neox_style=is_neox_style,
+            partial_rotary_factor=self.partial_rotary_factor,
+        )
+
+
+class MotifDecoderLayer(nn.Module):
+
+    def __init__(
+        self,
+        config: PretrainedConfig,
+        cache_config: Optional[CacheConfig] = None,
+        quant_config: Optional[QuantizationConfig] = None,
+        prefix: str = "",
+    ) -> None:
+        super().__init__()
+        self.hidden_size = config.hidden_size
+        rope_theta = getattr(config, "rope_theta", 10000)
+        rope_scaling = getattr(config, "rope_scaling", None)
+        if rope_scaling is not None and getattr(
+                config, "original_max_position_embeddings", None):
+            rope_scaling["original_max_position_embeddings"] = (
+                config.original_max_position_embeddings)
+        max_position_embeddings = getattr(config, "max_position_embeddings",
+                                          8192)
+        attention_bias = getattr(config, "attention_bias", False) or getattr(
+            config, "use_bias", False)
+        bias_o_proj = attention_bias
+        if hasattr(config, 'qkv_bias'):
+            attention_bias = config.qkv_bias
+
+        # By default, Motif uses causal attention as it is a decoder-only model.
+        # You can override the HF config with `is_causal=False` to enable
+        # bidirectional attention, which is used in some embedding models
+        # (e.g. parasail-ai/GritLM-7B-vllm)
+        if getattr(config, "is_causal", True):
+            attn_type = AttentionType.DECODER
+        else:
+            attn_type = AttentionType.ENCODER_ONLY
+
+        self.self_attn = MotifAttention(
+            config=config,
+            hidden_size=self.hidden_size,
+            num_heads=config.num_attention_heads,
+            num_kv_heads=getattr(config, "num_key_value_heads",
+                                 config.num_attention_heads),
+            rope_theta=rope_theta,
+            rope_scaling=rope_scaling,
+            max_position_embeddings=max_position_embeddings,
+            quant_config=quant_config,
+            bias=attention_bias,
+            bias_o_proj=bias_o_proj,
+            cache_config=cache_config,
+            prefix=f"{prefix}.self_attn",
+            attn_type=attn_type,
+        )
+        self.mlp = MotifMLP(
+            hidden_size=self.hidden_size,
+            intermediate_size=config.intermediate_size,
+            hidden_act=config.hidden_act,
+            quant_config=quant_config,
+            bias=getattr(config, "use_bias", False),
+            prefix=f"{prefix}.mlp",
+        )
+        self.input_layernorm = RMSNorm(config.hidden_size,
+                                       eps=config.rms_norm_eps)
+        self.post_attention_layernorm = RMSNorm(config.hidden_size,
+                                                eps=config.rms_norm_eps)
+
+    def forward(
+        self,
+        positions: torch.Tensor,
+        hidden_states: torch.Tensor,
+        residual: Optional[torch.Tensor],
+    ) -> tuple[torch.Tensor, torch.Tensor]:
+        # Self Attention
+        if residual is None:
+            residual = hidden_states
+            hidden_states = self.input_layernorm(hidden_states)
+        else:
+            hidden_states, residual = self.input_layernorm(
+                hidden_states, residual)
+        hidden_states = self.self_attn(positions=positions,
+                                       hidden_states=hidden_states)
+
+        # Fully Connected
+        hidden_states, residual = self.post_attention_layernorm(
+            hidden_states, residual)
+        hidden_states = self.mlp(hidden_states)
+        return hidden_states, residual
+
+
+# Motif model uses differential attention
+# Only supported in v0 (no chunked prefill support)
+class MotifForCausalLM(LlamaForCausalLM, SupportsV0Only):
+
+    def __init__(self,
+                 *,
+                 vllm_config: VllmConfig,
+                 prefix: str = "",
+                 layer_type: type[nn.Module] = MotifDecoderLayer):
+
+        # Prefix caching and chunked prefill is not supported for this model.
+        assert not vllm_config.cache_config.enable_prefix_caching, \
+            "Motif currently does not support prefix caching"
+        assert not vllm_config.scheduler_config.chunked_prefill_enabled, \
+            "Motif currently does not support chunked prefill"
+
+        super().__init__(vllm_config=vllm_config,
+                         prefix=prefix,
+                         layer_type=layer_type)
+
+
+MotifForSequenceClassification = as_seq_cls_model(MotifForCausalLM)

vllm/model_executor/models/registry.py

@@ -110,6 +110,7 @@ _TEXT_GENERATION_MODELS = {
     "MiniCPM3ForCausalLM": ("minicpm3", "MiniCPM3ForCausalLM"),
     "MistralForCausalLM": ("llama", "LlamaForCausalLM"),
     "MixtralForCausalLM": ("mixtral", "MixtralForCausalLM"),
+    "MotifForCausalLM": ("motif", "MotifForCausalLM"),
     # transformers's mpt class has lower case
     "MptForCausalLM": ("mpt", "MPTForCausalLM"),
     "MPTForCausalLM": ("mpt", "MPTForCausalLM"),