Add mamba kernel (#10234)

sgl-kernel/CMakeLists.txt

@@ -303,6 +303,7 @@ set(SOURCES
     "csrc/moe/cutlass_moe/w4a8/w4a8_moe_data.cu"
     "csrc/moe/cutlass_moe/w4a8/w4a8_grouped_mm_c3x.cu"
     "csrc/moe/marlin_moe_wna16/ops.cu"
+    "csrc/mamba/causal_conv1d.cu"
     "csrc/moe/moe_align_kernel.cu"
     "csrc/moe/moe_fused_gate.cu"
     "csrc/moe/moe_topk_softmax_kernels.cu"

sgl-kernel/csrc/common_extension.cc

@@ -438,6 +438,31 @@ TORCH_LIBRARY_FRAGMENT(sgl_kernel, m) {
   m.impl("copy_to_gpu_no_ce", torch::kCUDA, &copy_to_gpu_no_ce);
   m.def("concat_mla_k(Tensor! k, Tensor k_nope, Tensor k_rope) -> ()");
   m.impl("concat_mla_k", torch::kCUDA, &concat_mla_k);
+
+  /*
+   * From csrc/mamba
+   */
+  m.def(
+      "causal_conv1d_update(Tensor! x,"
+      "Tensor! conv_state,"
+      "Tensor! weight,"
+      "Tensor? bias_,"
+      "bool silu_activation,"
+      "Tensor? cache_seqlens_,"
+      "Tensor? conv_state_indices,"
+      "int pad_slot_id) -> ()");
+  m.impl("causal_conv1d_update", torch::kCUDA, &causal_conv1d_update);
+
+  m.def(
+      "causal_conv1d_fwd(Tensor! x, Tensor! weight,"
+      "Tensor? bias_,"
+      "Tensor!? conv_states,"
+      "Tensor? query_start_loc,"
+      "Tensor? cache_indices,"
+      "Tensor? has_initial_state,"
+      "bool silu_activation,"
+      "int pad_slot_id) -> ()");
+  m.impl("causal_conv1d_fwd", torch::kCUDA, &causal_conv1d_fwd);
 }
 
 REGISTER_EXTENSION(common_ops)

sgl-kernel/csrc/mamba/causal_conv1d.h

+/******************************************************************************
+ * Copyright (c) 2024, Tri Dao.
+ ******************************************************************************/
+// clang-format off
+// adapted from https://github.com/Dao-AILab/causal-conv1d/blob/main/csrc/causal_conv1d.h
+#pragma once
+
+#include <cuda_bf16.h>
+#include <cuda_fp16.h>
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+struct ConvParamsBase {
+    using index_t = uint32_t;
+
+    int batch, dim, seqlen, width;
+    int64_t pad_slot_id;
+    bool silu_activation;
+
+    index_t x_batch_stride;
+    index_t x_c_stride;
+    index_t x_l_stride;
+    index_t weight_c_stride;
+    index_t weight_width_stride;
+    index_t out_batch_stride;
+    index_t out_c_stride;
+    index_t out_l_stride;
+
+    int conv_state_len;
+    index_t conv_state_batch_stride;
+    index_t conv_state_c_stride;
+    index_t conv_state_l_stride;
+
+    // Common data pointers.
+    void *__restrict__ x_ptr;
+    void *__restrict__ weight_ptr;
+    void *__restrict__ bias_ptr;
+    void *__restrict__ out_ptr;
+
+    void *__restrict__ conv_state_ptr;
+    void *__restrict__ query_start_loc_ptr;
+    void *__restrict__ has_initial_state_ptr;
+    void *__restrict__ cache_indices_ptr;
+    int32_t *__restrict__ cache_seqlens;
+
+    // For the continuous batching case. Makes it so that the mamba state for
+    // the current batch doesn't need to be a contiguous tensor.
+    int32_t *__restrict__ conv_state_indices_ptr;
+
+    void *__restrict__ seq_idx_ptr;
+
+    // No __restrict__ since initial_states could be the same as final_states.
+    void * initial_states_ptr;
+    index_t initial_states_batch_stride;
+    index_t initial_states_l_stride;
+    index_t initial_states_c_stride;
+
+    void * final_states_ptr;
+    index_t final_states_batch_stride;
+    index_t final_states_l_stride;
+    index_t final_states_c_stride;
+
+    void *  conv_states_ptr;
+    index_t conv_states_batch_stride;
+    index_t conv_states_l_stride;
+    index_t conv_states_c_stride;
+};
+
+
+#ifndef USE_ROCM
+    #include <cuda_bf16.h>
+
+    template<typename T>
+    __device__ inline T shuffle_xor(T val, int offset) {
+        return __shfl_xor_sync(uint32_t(-1), val, offset);
+    }
+
+    constexpr size_t custom_max(std::initializer_list<size_t> ilist)
+    {
+        return std::max(ilist);
+    }
+
+    template<typename T>
+    constexpr T constexpr_min(T a, T b) {
+        return std::min(a, b);
+    }
+
+#else
+    #include <hip/hip_bf16.h>
+
+    template<typename T>
+    __device__ inline T shuffle_xor(T val, int offset) {
+        return __shfl_xor(val, offset);
+    }
+    constexpr size_t custom_max(std::initializer_list<size_t> ilist)
+    {
+        return *std::max_element(ilist.begin(), ilist.end());
+    }
+
+    template<typename T>
+    constexpr T constexpr_min(T a, T b) {
+        return a < b ? a : b;
+    }
+#endif
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<int BYTES> struct BytesToType {};
+
+template<> struct BytesToType<16> {
+    using Type = uint4;
+    static_assert(sizeof(Type) == 16);
+};
+
+template<> struct BytesToType<8> {
+    using Type = uint64_t;
+    static_assert(sizeof(Type) == 8);
+};
+
+template<> struct BytesToType<4> {
+    using Type = uint32_t;
+    static_assert(sizeof(Type) == 4);
+};
+
+template<> struct BytesToType<2> {
+    using Type = uint16_t;
+    static_assert(sizeof(Type) == 2);
+};
+
+template<> struct BytesToType<1> {
+    using Type = uint8_t;
+    static_assert(sizeof(Type) == 1);
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+template<typename T>
+struct SumOp {
+__device__ inline T operator()(T const & x, T const & y) { return x + y; }
+};
+
+template<int THREADS>
+struct Allreduce {
+    static_assert(THREADS == 32 || THREADS == 16 || THREADS == 8 || THREADS == 4);
+    template<typename T, typename Operator>
+    static __device__ inline T run(T x, Operator &op) {
+        constexpr int OFFSET = THREADS / 2;
+        x = op(x, __shfl_xor_sync(uint32_t(-1), x, OFFSET));
+        return Allreduce<OFFSET>::run(x, op);
+    }
+};
+
+template<>
+struct Allreduce<2> {
+template<typename T, typename Operator>
+static __device__ inline T run(T x, Operator &op) {
+    x = op(x, __shfl_xor_sync(uint32_t(-1), x, 1));
+    return x;
+}
+};

sgl-kernel/include/sgl_kernel_ops.h

@@ -724,3 +724,27 @@ void store_kv_cache(at::Tensor k_cache, at::Tensor v_cache, at::Tensor out_loc,
 
 void copy_to_gpu_no_ce(const at::Tensor& input, at::Tensor& output);
 void concat_mla_k(torch::Tensor k, torch::Tensor k_nope, torch::Tensor k_rope);
+
+/*
+ * From csrc/mamba
+ */
+void causal_conv1d_update(
+    const at::Tensor& x,
+    const at::Tensor& conv_state,
+    const at::Tensor& weight,
+    const std::optional<at::Tensor>& bias_,
+    bool silu_activation,
+    const std::optional<at::Tensor>& cache_seqlens_,
+    const std::optional<at::Tensor>& conv_state_indices_,
+    int64_t pad_slot_id);
+
+void causal_conv1d_fwd(
+    const at::Tensor& x,
+    const at::Tensor& weight,
+    const std::optional<at::Tensor>& bias_,
+    const std::optional<at::Tensor>& conv_states,
+    const std::optional<at::Tensor>& query_start_loc,
+    const std::optional<at::Tensor>& cache_indices,
+    const std::optional<at::Tensor>& has_initial_state,
+    bool silu_activation,
+    int64_t pad_slot_id);

sgl-kernel/python/sgl_kernel/__init__.py

@@ -34,6 +34,7 @@ from sgl_kernel.elementwise import (
     rmsnorm,
     silu_and_mul,
 )
+from sgl_kernel.mamba import causal_conv1d_fwd, causal_conv1d_update
 
 if torch.version.hip is not None:
     from sgl_kernel.elementwise import gelu_quick

sgl-kernel/python/sgl_kernel/mamba.py

+from typing import Optional
+
+import torch
+
+
+# mamba
+def causal_conv1d_fwd(
+    x: torch.Tensor,
+    weight: torch.Tensor,
+    bias_: Optional[torch.Tensor],
+    conv_states: Optional[torch.Tensor],
+    query_start_loc: Optional[torch.Tensor],
+    cache_indices: Optional[torch.Tensor],
+    has_initial_state: Optional[torch.Tensor],
+    silu_activation: bool,
+    pad_slot_id: int,
+):
+    torch.ops.sgl_kernel.causal_conv1d_fwd(
+        x,
+        weight,
+        bias_,
+        conv_states,
+        query_start_loc,
+        cache_indices,
+        has_initial_state,
+        silu_activation,
+        pad_slot_id,
+    )
+
+
+def causal_conv1d_update(
+    x: torch.Tensor,
+    conv_state: torch.Tensor,
+    weight: torch.Tensor,
+    bias_: Optional[torch.Tensor],
+    silu_activation: bool,
+    cache_seqlens: Optional[torch.Tensor],
+    conv_state_indices: Optional[torch.Tensor],
+    pad_slot_id: int,
+):
+    torch.ops.sgl_kernel.causal_conv1d_update(
+        x,
+        conv_state,
+        weight,
+        bias_,
+        silu_activation,
+        cache_seqlens,
+        conv_state_indices,
+        pad_slot_id,
+    )

sgl-kernel/tests/test_causal_conv1d.py

+# Adapted from https://github.com/vllm-project/vllm/blob/main/tests/kernels/mamba/test_causal_conv1d.py
+from typing import Optional
+
+import torch
+from sgl_kernel import causal_conv1d_fwd
+from sgl_kernel import causal_conv1d_update as causal_conv1d_update_kernel
+
+PAD_SLOT_ID = -1
+
+
+def causal_conv1d_fn(
+    x: torch.Tensor,
+    weight: torch.Tensor,
+    bias: Optional[torch.Tensor] = None,
+    query_start_loc: Optional[torch.Tensor] = None,
+    cache_indices: Optional[torch.Tensor] = None,
+    has_initial_state: Optional[torch.Tensor] = None,
+    conv_states: Optional[torch.Tensor] = None,
+    activation: Optional[str] = "silu",
+    pad_slot_id: int = PAD_SLOT_ID,
+):
+    """
+    x: (batch, dim, seqlen) or (dim,cu_seq_len) for varlen
+        sequences are concatenated from left to right for varlen
+    weight: (dim, width)
+    bias: (dim,)
+    query_start_loc: (batch + 1) int32
+        The cumulative sequence lengths of the sequences in
+        the batch, used to index into sequence. prepended by 0.
+        for example: query_start_loc = torch.Tensor([0,10,16,17]),
+        x.shape=(dim,17)
+    cache_indices: (batch)  int32
+        indicates the corresponding state index,
+        like so: conv_state = conv_states[cache_indices[batch_id]]
+    has_initial_state: (batch) bool
+        indicates whether should the kernel take the current state as initial
+        state for the calculations
+    conv_states: (...,dim,width - 1) itype
+        updated inplace if provided
+    activation: either None or "silu" or "swish"
+    pad_slot_id: int
+            if cache_indices is passed, lets the kernel identify padded
+            entries that will not be processed,
+            for example: cache_indices = [pad_slot_id, 1, 20, pad_slot_id]
+            in this case, the kernel will not process entries at
+            indices 0 and 3
+    out: (batch, dim, seqlen)
+    """
+    if activation not in [None, "silu", "swish"]:
+        raise NotImplementedError("activation must be None, silu, or swish")
+    if x.stride(-1) != 1:
+        x = x.contiguous()
+    bias = bias.contiguous() if bias is not None else None
+
+    causal_conv1d_fwd(
+        x,
+        weight,
+        bias,
+        conv_states,
+        query_start_loc,
+        cache_indices,
+        has_initial_state,
+        activation in ["silu", "swish"],
+        pad_slot_id,
+    )
+    return x
+
+
+def causal_conv1d_update(
+    x: torch.Tensor,
+    conv_state: torch.Tensor,
+    weight: torch.Tensor,
+    bias: Optional[torch.Tensor] = None,
+    activation: Optional[str] = None,
+    cache_seqlens: Optional[torch.Tensor] = None,
+    conv_state_indices: Optional[torch.Tensor] = None,
+    pad_slot_id: int = PAD_SLOT_ID,
+):
+    """
+    x: (batch, dim) or (batch, dim, seqlen)
+    conv_state: (batch, dim, state_len), where state_len >= width - 1
+    weight: (dim, width)
+    bias: (dim,)
+    cache_seqlens: (batch,), dtype int32.
+        If not None, the conv_state is treated as a circular buffer.
+        The conv_state will be updated by copying x to the conv_state
+        starting at the index
+        @cache_seqlens % state_len.
+    conv_state_indices: (batch,), dtype int32
+        If not None, the conv_state is a larger tensor along the batch dim,
+        and we are selecting the batch coords specified by conv_state_indices.
+        Useful for a continuous batching scenario.
+    pad_slot_id: int
+            if cache_indices is passed, lets the kernel identify padded
+            entries that will not be processed,
+            for example: cache_indices = [pad_slot_id, 1 ,20 ,pad_slot_id]
+            in this case, the kernel will not process entries at
+            indices 0 and 3
+    out: (batch, dim) or (batch, dim, seqlen)
+    """
+    if activation not in [None, "silu", "swish"]:
+        raise NotImplementedError(
+            f"activation must be None, silu, or swish, actual: {activation}"
+        )
+    activation_val = activation in ["silu", "swish"]
+    unsqueeze = x.dim() == 2
+    if unsqueeze:
+        x = x.unsqueeze(-1)
+    causal_conv1d_update_kernel(
+        x,
+        conv_state,
+        weight,
+        bias,
+        activation_val,
+        cache_seqlens,
+        conv_state_indices,
+        pad_slot_id,
+    )
+    if unsqueeze:
+        x = x.squeeze(-1)
+    return x
+
+
+# SPDX-License-Identifier: Apache-2.0
+
+from typing import Optional
+
+import pytest
+import torch
+import torch.nn.functional as F
+
+
+def causal_conv1d_ref(
+    x: torch.Tensor,
+    weight: torch.Tensor,
+    bias: Optional[torch.Tensor] = None,
+    initial_states: Optional[torch.Tensor] = None,
+    return_final_states: bool = False,
+    final_states_out: Optional[torch.Tensor] = None,
+    activation: Optional[str] = "silu",
+):
+    """
+    x: (batch, dim, seqlen)
+    weight: (dim, width)
+    bias: (dim,)
+    initial_states: (batch, dim, width - 1)
+    final_states_out: (batch, dim, width - 1)
+
+    out: (batch, dim, seqlen)
+    """
+    if activation not in [None, "silu", "swish"]:
+        raise NotImplementedError("activation must be None, silu, or swish")
+    dtype_in = x.dtype
+    x = x.to(weight.dtype)
+    seqlen = x.shape[-1]
+    dim, width = weight.shape
+    if initial_states is None:
+        out = F.conv1d(x, weight.unsqueeze(1), bias, padding=width - 1, groups=dim)
+    else:
+        x = torch.cat([initial_states, x], dim=-1)
+        out = F.conv1d(x, weight.unsqueeze(1), bias, padding=0, groups=dim)
+    out = out[..., :seqlen]
+    if return_final_states:
+        final_states = F.pad(x, (width - 1 - x.shape[-1], 0)).to(
+            dtype_in
+        )  # (batch, dim, width - 1)
+        if final_states_out is not None:
+            final_states_out.copy_(final_states)
+        else:
+            final_states_out = final_states
+    out = (out if activation is None else F.silu(out)).to(dtype=dtype_in)
+    return (out, None) if not return_final_states else (out, final_states_out)
+
+
+def causal_conv1d_update_ref(
+    x, conv_state, weight, bias=None, activation=None, cache_seqlens=None
+):
+    """
+    x: (batch, dim) or (batch, dim, seqlen)
+    conv_state: (batch, dim, state_len), where state_len >= width - 1
+    weight: (dim, width)
+    bias: (dim,)
+    cache_seqlens: (batch,), dtype int32.
+        If not None, the conv_state is treated as a circular buffer.
+        The conv_state will be updated by copying x to the
+        conv_state starting at the index
+        @cache_seqlens % state_len before performing the convolution.
+
+    out: (batch, dim) or (batch, dim, seqlen)
+    """
+    if activation not in [None, "silu", "swish"]:
+        raise NotImplementedError("activation must be None, silu, or swish")
+    dtype_in = x.dtype
+    unsqueeze = x.dim() == 2
+    if unsqueeze:
+        x = x.unsqueeze(-1)
+    batch, dim, seqlen = x.shape
+    width = weight.shape[1]
+    state_len = conv_state.shape[-1]
+    assert conv_state.shape == (batch, dim, state_len)
+    assert weight.shape == (dim, width)
+    if cache_seqlens is None:
+        x_new = torch.cat([conv_state, x], dim=-1).to(
+            weight.dtype
+        )  # (batch, dim, state_len + seqlen)
+        conv_state.copy_(x_new[:, :, -state_len:])
+    else:
+        width_idx = torch.arange(
+            -(width - 1), 0, dtype=torch.long, device=x.device
+        ).unsqueeze(0) + cache_seqlens.unsqueeze(1)
+        width_idx = (
+            torch.remainder(width_idx, state_len).unsqueeze(1).expand(-1, dim, -1)
+        )
+        x_new = torch.cat([conv_state.gather(2, width_idx), x], dim=-1).to(weight.dtype)
+        copy_idx = torch.arange(seqlen, dtype=torch.long, device=x.device).unsqueeze(
+            0
+        ) + cache_seqlens.unsqueeze(1)
+        copy_idx = torch.remainder(copy_idx, state_len).unsqueeze(1).expand(-1, dim, -1)
+        conv_state.scatter_(2, copy_idx, x)
+    out = F.conv1d(x_new, weight.unsqueeze(1), bias, padding=0, groups=dim)[
+        :, :, -seqlen:
+    ]
+    if unsqueeze:
+        out = out.squeeze(-1)
+    return (out if activation is None else F.silu(out)).to(dtype=dtype_in)
+
+
+@pytest.mark.parametrize("itype", [torch.bfloat16, torch.float])
+@pytest.mark.parametrize("silu_activation", [True])
+@pytest.mark.parametrize("has_bias", [True])
+@pytest.mark.parametrize("has_initial_state", [True, False])
+@pytest.mark.parametrize("width", [4])
+@pytest.mark.parametrize(
+    "seqlen", [1, 8, 16, 32, 64, 128, 256, 512, 784, 1024, 1025, 2048, 4096]
+)
+@pytest.mark.parametrize("dim", [64])
+@pytest.mark.parametrize("batch", [1])
+def test_causal_conv1d(
+    batch, dim, seqlen, width, has_bias, silu_activation, has_initial_state, itype
+):
+    device = "cuda"
+    rtol, atol = (3e-4, 1e-3) if itype == torch.float32 else (3e-3, 5e-3)
+    if itype == torch.bfloat16:
+        rtol, atol = 1e-2, 5e-2
+    x = torch.randn(batch, dim, seqlen, device=device, dtype=itype).contiguous()
+
+    weight = torch.randn(dim, width, device=device, dtype=itype)
+    bias = torch.randn(dim, device=device, dtype=itype) if has_bias else None
+    if has_initial_state:
+        initial_states = torch.randn(batch, dim, width - 1, device=device, dtype=itype)
+        has_initial_state_tensor = torch.ones(batch, dtype=torch.bool, device=x.device)
+    else:
+        initial_states = None
+        has_initial_state_tensor = None
+    x_ref = x.clone()
+    weight_ref = weight.clone()
+    bias_ref = bias.clone() if bias is not None else None
+    initial_states_ref = initial_states.clone() if initial_states is not None else None
+    activation = None if not silu_activation else "silu"
+    out = causal_conv1d_fn(
+        x,
+        weight,
+        bias,
+        activation=activation,
+        conv_states=initial_states,
+        has_initial_state=has_initial_state_tensor,
+    )
+    out_ref, final_states_ref = causal_conv1d_ref(
+        x_ref,
+        weight_ref,
+        bias_ref,
+        initial_states=initial_states_ref,
+        return_final_states=True,
+        activation=activation,
+    )
+    if has_initial_state:
+        assert initial_states is not None and final_states_ref is not None
+        assert torch.allclose(initial_states, final_states_ref, rtol=rtol, atol=atol)
+    assert torch.allclose(out, out_ref, rtol=rtol, atol=atol)
+
+
+@pytest.mark.parametrize("itype", [torch.bfloat16])
+@pytest.mark.parametrize("silu_activation", [False, True])
+@pytest.mark.parametrize("has_bias", [False, True])
+@pytest.mark.parametrize("seqlen", [1])
+@pytest.mark.parametrize("width", [4])
+@pytest.mark.parametrize("dim", [2048, 2048 + 16, 4096])
+def test_causal_conv1d_update(dim, width, seqlen, has_bias, silu_activation, itype):
+    device = "cuda"
+    rtol, atol = (3e-4, 1e-3) if itype == torch.float32 else (3e-3, 5e-3)
+    if itype == torch.bfloat16:
+        rtol, atol = 1e-2, 5e-2
+
+    batch = 2
+    x = torch.randn(batch, dim, seqlen, device=device, dtype=itype)
+    x_ref = x.clone()
+    conv_state = torch.randn(batch, dim, width - 1, device=device, dtype=itype)
+
+    weight = torch.randn(dim, width, device=device, dtype=itype)
+    bias = torch.randn(dim, device=device, dtype=itype) if has_bias else None
+    conv_state_ref = conv_state.detach().clone()
+    activation = None if not silu_activation else "silu"
+    out = causal_conv1d_update(x, conv_state, weight, bias, activation=activation)
+    out_ref = causal_conv1d_update_ref(
+        x_ref, conv_state_ref, weight, bias, activation=activation
+    )
+
+    assert torch.equal(conv_state, conv_state_ref)
+    assert torch.allclose(out, out_ref, rtol=rtol, atol=atol)
+
+
+@pytest.mark.parametrize("itype", [torch.float32, torch.float16, torch.bfloat16])
+@pytest.mark.parametrize("silu_activation", [False, True])
+@pytest.mark.parametrize("has_bias", [False, True])
+@pytest.mark.parametrize("seqlen", [1, 4, 5])
+@pytest.mark.parametrize("width", [2, 3, 4])
+@pytest.mark.parametrize("dim", [2048, 2048 + 16, 4096])
+# tests correctness in case subset of the sequences are padded
+@pytest.mark.parametrize("with_padding", [True, False])
+def test_causal_conv1d_update_with_batch_gather(
+    with_padding, dim, width, seqlen, has_bias, silu_activation, itype
+):
+    device = "cuda"
+    rtol, atol = (3e-4, 1e-3) if itype == torch.float32 else (3e-3, 5e-3)
+    if itype == torch.bfloat16:
+        rtol, atol = 1e-2, 5e-2
+
+    batch_size = 3
+    padding = 5 if with_padding else 0
+    padded_batch_size = batch_size + padding
+    total_entries = 10 * batch_size
+
+    x = torch.randn(padded_batch_size, dim, 1, device=device, dtype=itype)
+    x_ref = x.clone()
+
+    conv_state_indices = torch.randperm(total_entries)[:batch_size].to(
+        dtype=torch.int32, device=device
+    )
+    unused_states_bool = torch.ones(total_entries, dtype=torch.bool, device=device)
+    unused_states_bool[conv_state_indices] = False
+    padded_state_indices = torch.concat(
+        [
+            conv_state_indices,
+            torch.as_tensor([PAD_SLOT_ID] * padding, dtype=torch.int32, device=device),
+        ],
+        dim=0,
+    )
+    conv_state = torch.randn(total_entries, dim, width - 1, device=device, dtype=itype)
+    conv_state_for_padding_test = conv_state.clone()
+
+    weight = torch.randn(dim, width, device=device, dtype=itype)
+    bias = torch.randn(dim, device=device, dtype=itype) if has_bias else None
+    conv_state_ref = conv_state[conv_state_indices, :].detach().clone()
+    activation = None if not silu_activation else "silu"
+    out = causal_conv1d_update(
+        x,
+        conv_state,
+        weight,
+        bias,
+        activation=activation,
+        conv_state_indices=padded_state_indices,
+        pad_slot_id=PAD_SLOT_ID,
+    )
+    out_ref = causal_conv1d_update_ref(
+        x_ref[:batch_size], conv_state_ref, weight, bias, activation=activation
+    )
+
+    assert torch.equal(conv_state[conv_state_indices, :], conv_state_ref)
+    assert torch.allclose(out[:batch_size], out_ref, rtol=rtol, atol=atol)
+    assert torch.equal(
+        conv_state[unused_states_bool], conv_state_for_padding_test[unused_states_bool]
+    )
+
+
+@pytest.mark.parametrize("itype", [torch.bfloat16])
+@pytest.mark.parametrize("silu_activation", [True])
+@pytest.mark.parametrize("has_bias", [True])
+@pytest.mark.parametrize("width", [4])
+@pytest.mark.parametrize(
+    "seqlen", [8, 16, 32, 64, 128, 256, 512, 784, 1024, 2048, 2049, 4096]
+)
+@pytest.mark.parametrize("dim", [64, 4096])
+# tests correctness in case subset of the sequences are padded
+@pytest.mark.parametrize("with_padding", [True, False])
+def test_causal_conv1d_varlen(
+    with_padding, dim, seqlen, width, has_bias, silu_activation, itype
+):
+    device = "cuda"
+    torch.cuda.empty_cache()
+    rtol, atol = (3e-4, 1e-3) if itype == torch.float32 else (3e-3, 5e-3)
+    if itype == torch.bfloat16:
+        rtol, atol = 1e-2, 5e-2
+
+    seqlens = []
+    batch_size = 4
+    if seqlen < 10:
+        batch_size = 1
+    padding = 3 if with_padding else 0
+    padded_batch_size = batch_size + padding
+    nsplits = padded_batch_size - 1
+
+    eos_pos = torch.randperm(seqlen - 1)[:nsplits].sort().values
+    seqlens.append(
+        torch.diff(
+            torch.cat([torch.tensor([-1]), eos_pos, torch.tensor([seqlen - 1])])
+        ).tolist()
+    )
+    assert sum(seqlens[-1]) == seqlen
+    assert all(s > 0 for s in seqlens[-1])
+
+    total_entries = batch_size * 10
+    cumsum = torch.cumsum(torch.tensor(seqlens[0]), dim=0).to(torch.int32)
+    cumsum = torch.concat([torch.tensor([0], dtype=torch.int32), cumsum], dim=0)
+    x = torch.randn(1, 4096 + dim + 64, seqlen, device=device, dtype=itype)[
+        :, 4096 : 4096 + dim, :
+    ]
+    weight = torch.randn(dim, width, device=device, dtype=itype)
+    bias = torch.randn(dim, device=device, dtype=itype) if has_bias else None
+    x_ref = x.clone()
+    weight_ref = weight.clone()
+    bias_ref = bias.clone() if bias is not None else None
+    activation = None if not silu_activation else "silu"
+    final_states = torch.randn(
+        total_entries, dim, width - 1, device=x.device, dtype=x.dtype
+    )
+    final_states_ref = final_states.clone()
+    has_initial_states = torch.randint(
+        0, 2, (cumsum.shape[0] - 1,), dtype=torch.bool, device=x.device
+    )
+    state_indices = torch.randperm(total_entries, dtype=torch.int32, device=x.device)[
+        :batch_size
+    ]
+    padded_state_indices = torch.concat(
+        [
+            state_indices,
+            torch.as_tensor([PAD_SLOT_ID] * padding, dtype=torch.int32, device=device),
+        ],
+        dim=-1,
+    )
+
+    out = causal_conv1d_fn(
+        x.squeeze(0),
+        weight,
+        bias,
+        cumsum.cuda(),
+        padded_state_indices,
+        has_initial_states,
+        final_states,
+        activation,
+        PAD_SLOT_ID,
+    )
+    out_ref = []
+    out_ref_b = []
+
+    splits = [torch.split(var, seqlens[0], dim=-1) for var in (x_ref)]
+    for i in range(len(seqlens[0])):
+        x_s = [v[i].unsqueeze(0) for v in splits][0]
+        if padded_state_indices[i] == PAD_SLOT_ID:
+            continue
+        out_ref_b.append(
+            causal_conv1d_ref(
+                x_s,
+                weight_ref,
+                bias_ref,
+                activation=activation,
+                return_final_states=True,
+                final_states_out=final_states_ref[padded_state_indices[i]].unsqueeze(0),
+                initial_states=(
+                    final_states_ref[padded_state_indices[i]].unsqueeze(0)
+                    if has_initial_states[i]
+                    else None
+                ),
+            )
+        )
+    out_ref.append(torch.cat([t[0] for t in out_ref_b], dim=2))
+    out_ref_tensor = torch.cat(out_ref, dim=0)
+
+    unpadded_out = out[:, : out_ref_tensor.shape[-1]]
+    assert torch.allclose(unpadded_out, out_ref_tensor, rtol=rtol, atol=atol)
+    assert torch.allclose(
+        final_states[state_indices],
+        final_states_ref[state_indices],
+        rtol=rtol,
+        atol=atol,
+    )
+
+
+if __name__ == "__main__":
+    pytest.main([__file__])