[Diffusion] Restruct and clean Diffusion rotary embedding (#19064)

This commit is contained in:
Xiaoyu Zhang
2026-02-21 21:41:47 +08:00
committed by GitHub
parent d8d0208c63
commit 66497ab0aa
6 changed files with 862 additions and 1029 deletions

File diff suppressed because it is too large Load Diff

View File

@@ -0,0 +1,48 @@
# Copied and adapted from: https://github.com/hao-ai-lab/FastVideo
# SPDX-License-Identifier: Apache-2.0
# Adapted from vllm: https://github.com/vllm-project/vllm/blob/v0.7.3/vllm/model_executor/layers/rotary_embedding.py
# Adapted from
# https://github.com/huggingface/transformers/blob/v4.33.2/src/transformers/models/llama/modeling_llama.py
# Copyright 2023 The vLLM team.
# Copyright 2022 EleutherAI and the HuggingFace Inc. team. All rights reserved.
#
# This code is based on EleutherAI's GPT-NeoX library and the GPT-NeoX
# and OPT implementations in this library. It has been modified from its
# original forms to accommodate minor architectural differences compared
# to GPT-NeoX and OPT used by the Meta AI team that trained the model.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Rotary Positional Embeddings — unified public API (drop-in replacement)."""
from ._base import RotaryEmbedding
from ._factory import get_rope, get_rotary_pos_embed
from ._mrope import NDRotaryEmbedding
from ._utils import (
_apply_rotary_emb,
apply_flashinfer_rope_qk_inplace,
)
__all__ = [
# _utils
"_apply_rotary_emb",
"apply_flashinfer_rope_qk_inplace",
# _base
"RotaryEmbedding",
# _mrope
"NDRotaryEmbedding",
# _factory
"get_rope",
"get_rotary_pos_embed",
]

View File

@@ -0,0 +1,130 @@
"""RotaryEmbedding base class and LinearScalingRotaryEmbedding variant."""
import torch
from sglang.multimodal_gen.runtime.layers.custom_op import CustomOp
from ._utils import _apply_rotary_emb
@CustomOp.register("rotary_embedding")
class RotaryEmbedding(CustomOp):
"""Original rotary positional embedding."""
def __init__(
self,
head_size: int,
rotary_dim: int,
max_position_embeddings: int,
base: int | float,
is_neox_style: bool,
dtype: torch.dtype,
) -> None:
super().__init__()
self.head_size = head_size
self.rotary_dim = rotary_dim
self.max_position_embeddings = max_position_embeddings
self.base = base
self.is_neox_style = is_neox_style
self.dtype = dtype
cache = self._compute_cos_sin_cache()
cache = cache.to(dtype)
self.cos_sin_cache: torch.Tensor
self.register_buffer("cos_sin_cache", cache, persistent=False)
def _compute_inv_freq(self, base: int | float) -> torch.Tensor:
"""Compute the inverse frequency."""
# NOTE(woosuk): To exactly match the HF implementation, we need to
# use CPU to compute the cache and then move it to GPU. However, we
# create the cache on GPU for faster initialization. This may cause
# a slight numerical difference between the HF implementation and ours.
inv_freq = 1.0 / (
base
** (
torch.arange(0, self.rotary_dim, 2, dtype=torch.float) / self.rotary_dim
)
)
return inv_freq
def _compute_cos_sin_cache(self) -> torch.Tensor:
"""Compute the cos and sin cache."""
inv_freq = self._compute_inv_freq(self.base)
t = torch.arange(self.max_position_embeddings, dtype=torch.float)
freqs = torch.einsum("i,j -> ij", t, inv_freq)
cos = freqs.cos()
sin = freqs.sin()
cache = torch.cat((cos, sin), dim=-1)
return cache
def forward_cuda(self, *args, **kwargs):
return self.forward_native(*args, **kwargs)
def forward_native(
self,
positions: torch.Tensor,
query: torch.Tensor,
key: torch.Tensor,
offsets: torch.Tensor | None = None,
) -> tuple[torch.Tensor, torch.Tensor]:
"""A PyTorch-native implementation of forward()."""
if offsets is not None:
positions = positions + offsets
positions = positions.flatten()
num_tokens = positions.shape[0]
cos_sin = self.cos_sin_cache.index_select(0, positions)
cos, sin = cos_sin.chunk(2, dim=-1)
query_shape = query.shape
query = query.view(num_tokens, -1, self.head_size)
query_rot = query[..., : self.rotary_dim]
query_pass = query[..., self.rotary_dim :]
query_rot = _apply_rotary_emb(query_rot, cos, sin, self.is_neox_style)
query = torch.cat((query_rot, query_pass), dim=-1).reshape(query_shape)
key_shape = key.shape
key = key.view(num_tokens, -1, self.head_size)
key_rot = key[..., : self.rotary_dim]
key_pass = key[..., self.rotary_dim :]
key_rot = _apply_rotary_emb(key_rot, cos, sin, self.is_neox_style)
key = torch.cat((key_rot, key_pass), dim=-1).reshape(key_shape)
return query, key
def extra_repr(self) -> str:
s = f"head_size={self.head_size}, rotary_dim={self.rotary_dim}"
s += f", max_position_embeddings={self.max_position_embeddings}"
s += f", base={self.base}, is_neox_style={self.is_neox_style}"
return s
class LinearScalingRotaryEmbedding(RotaryEmbedding):
def __init__(
self,
head_size: int,
rotary_dim: int,
max_position_embeddings: int,
base: int | float,
is_neox_style: bool,
dtype: torch.dtype,
scaling_factor: float,
) -> None:
self.scaling_factor = float(scaling_factor)
super().__init__(
head_size=head_size,
rotary_dim=rotary_dim,
max_position_embeddings=max_position_embeddings,
base=base,
is_neox_style=is_neox_style,
dtype=dtype,
)
def _compute_cos_sin_cache(self) -> torch.Tensor:
inv_freq = self._compute_inv_freq(self.base)
t = torch.arange(self.max_position_embeddings, dtype=torch.float)
t = t / self.scaling_factor
freqs = torch.einsum("i,j -> ij", t, inv_freq)
cos = freqs.cos()
sin = freqs.sin()
cache = torch.cat((cos, sin), dim=-1)
return cache

View File

@@ -0,0 +1,171 @@
"""get_rope / get_rotary_pos_embed factory functions and module-level caches."""
from collections import OrderedDict
from typing import Any
import torch
from ._base import LinearScalingRotaryEmbedding, RotaryEmbedding
from ._mrope import NDRotaryEmbedding, _to_tuple
_ROPE_DICT: dict[tuple, RotaryEmbedding] = {}
_ND_ROPE_CACHE: "OrderedDict[tuple, NDRotaryEmbedding]" = OrderedDict()
_ROPE_3D_CACHE: "OrderedDict[tuple, tuple[torch.Tensor, torch.Tensor]]" = OrderedDict()
def get_rope(
head_size: int,
rotary_dim: int,
max_position: int,
base: int | float,
is_neox_style: bool = True,
rope_scaling: dict[str, Any] | None = None,
dtype: torch.dtype | None = None,
partial_rotary_factor: float = 1.0,
) -> RotaryEmbedding:
if dtype is None:
dtype = torch.get_default_dtype()
if rope_scaling is not None:
# Transforms every value that is a list into a tuple for caching calls
rope_scaling_tuple = {
k: tuple(v) if isinstance(v, list) else v for k, v in rope_scaling.items()
}
rope_scaling_args = tuple(rope_scaling_tuple.items())
else:
rope_scaling_args = None
if partial_rotary_factor < 1.0:
rotary_dim = int(rotary_dim * partial_rotary_factor)
max_position_embeddings = max_position
rope_type = None
if rope_scaling is not None:
rope_type = rope_scaling.get("rope_type", rope_scaling.get("type", None))
if rope_type in (None, "default"):
rope_scaling = None
elif rope_type == "linear":
factor = float(rope_scaling.get("factor", 1.0))
original_max = rope_scaling.get("original_max_position_embeddings", None)
if original_max is not None:
max_position_embeddings = max(
max_position_embeddings, int(float(original_max) * factor)
)
key = (
head_size,
rotary_dim,
max_position_embeddings,
base,
is_neox_style,
rope_scaling_args,
dtype,
)
if key in _ROPE_DICT:
return _ROPE_DICT[key]
if rope_scaling is None:
rotary_emb = RotaryEmbedding(
head_size, rotary_dim, max_position_embeddings, base, is_neox_style, dtype
)
else:
if rope_type == "linear":
factor = float(rope_scaling.get("factor", 1.0))
rotary_emb = LinearScalingRotaryEmbedding(
head_size=head_size,
rotary_dim=rotary_dim,
max_position_embeddings=max_position_embeddings,
base=base,
is_neox_style=is_neox_style,
dtype=dtype,
scaling_factor=factor,
)
else:
raise ValueError(f"Unknown RoPE scaling {rope_scaling}")
_ROPE_DICT[key] = rotary_emb
return rotary_emb
def get_rotary_pos_embed(
rope_sizes,
hidden_size,
heads_num,
rope_dim_list,
rope_theta,
theta_rescale_factor=1.0,
interpolation_factor=1.0,
shard_dim: int = 0,
dtype: torch.dtype = torch.float32,
start_frame: int = 0,
device: torch.device | str | None = None,
) -> tuple[torch.Tensor, torch.Tensor]:
"""
Generate rotary positional embeddings for the given sizes.
Args:
rope_sizes: Tuple of dimensions (t, h, w)
hidden_size: Hidden dimension size
heads_num: Number of attention heads
rope_dim_list: List of dimensions for each axis, or None
rope_theta: Base for frequency calculations
theta_rescale_factor: Rescale factor for theta. Defaults to 1.0
interpolation_factor: Factor to scale positions. Defaults to 1.0
shard_dim: Which dimension to shard for sequence parallelism. Defaults to 0.
Returns:
Tuple of (cos, sin) tensors for rotary embeddings
"""
target_ndim = 3
head_dim = hidden_size // heads_num
if rope_dim_list is None:
rope_dim_list = [head_dim // target_ndim for _ in range(target_ndim)]
assert (
sum(rope_dim_list) == head_dim
), "sum(rope_dim_list) should equal to head_dim of attention layer"
# Get SP info - now handled within NDRotaryEmbedding
# sp_group = get_sp_group()
# sp_rank = sp_group.rank_in_group
# sp_world_size = sp_group.world_size
# Simple LRU cache keyed by parameters
global _ND_ROPE_CACHE
key = (
tuple(rope_dim_list),
float(rope_theta),
(
tuple(theta_rescale_factor)
if isinstance(theta_rescale_factor, list)
else float(theta_rescale_factor)
),
(
tuple(interpolation_factor)
if isinstance(interpolation_factor, list)
else float(interpolation_factor)
),
dtype,
)
cache_hit = key in _ND_ROPE_CACHE
if cache_hit:
rope_emb = _ND_ROPE_CACHE.pop(key)
_ND_ROPE_CACHE[key] = rope_emb # move to end (most-recent)
else:
rope_emb = NDRotaryEmbedding(
rope_dim_list=rope_dim_list,
rope_theta=rope_theta,
theta_rescale_factor=theta_rescale_factor,
interpolation_factor=interpolation_factor,
dtype=dtype,
)
_ND_ROPE_CACHE[key] = rope_emb
if len(_ND_ROPE_CACHE) > 16:
# pop least-recently-used
_ND_ROPE_CACHE.pop(next(iter(_ND_ROPE_CACHE)))
freqs_cos, freqs_sin = rope_emb.forward_from_grid(
grid_size=_to_tuple(rope_sizes, dim=3),
shard_dim=shard_dim,
start_frame=start_frame,
device=device,
)
return freqs_cos, freqs_sin

View File

@@ -0,0 +1,392 @@
"""MRotaryEmbedding, YaRNScalingMRotaryEmbedding, NDRotaryEmbedding, OneDRotaryEmbedding."""
import functools
import torch
from sglang.multimodal_gen.runtime.distributed.parallel_state import get_sp_group
def _to_tuple(x: int | tuple[int, ...], dim: int = 2) -> tuple[int, ...]:
if isinstance(x, int):
return (x,) * dim
elif len(x) == dim:
return x
else:
raise ValueError(f"Expected length {dim} or int, but got {x}")
def get_1d_rotary_pos_embed(
dim: int,
pos: torch.FloatTensor | int,
theta: float = 10000.0,
theta_rescale_factor: float = 1.0,
interpolation_factor: float = 1.0,
dtype: torch.dtype = torch.float32,
device: torch.device | str | None = None,
) -> tuple[torch.Tensor, torch.Tensor]:
"""
Precompute the frequency tensor for complex exponential (cis) with given dimensions.
(Note: `cis` means `cos + i * sin`, where i is the imaginary unit.)
This function calculates a frequency tensor with complex exponential using the given dimension 'dim'
and the end index 'end'. The 'theta' parameter scales the frequencies.
Args:
dim (int): Dimension of the frequency tensor.
pos (int or torch.FloatTensor): Position indices for the frequency tensor. [S] or scalar
theta (float, optional): Scaling factor for frequency computation. Defaults to 10000.0.
theta_rescale_factor (float, optional): Rescale factor for theta. Defaults to 1.0.
interpolation_factor (float, optional): Factor to scale positions. Defaults to 1.0.
Returns:
freqs_cos, freqs_sin: Precomputed frequency tensor with real and imaginary parts separately. [S, D]
"""
if isinstance(pos, int):
pos = torch.arange(pos, dtype=dtype, device=device)
elif (
isinstance(pos, torch.Tensor)
and device is not None
and pos.device != torch.device(device)
):
# Ensure positions are on the requested device to avoid implicit CPU ops.
pos = pos.to(device)
# proposed by reddit user bloc97, to rescale rotary embeddings to longer sequence length without fine-tuning
# has some connection to NTK literature
if theta_rescale_factor != 1.0:
theta *= theta_rescale_factor ** (dim / (dim - 2))
freqs = 1.0 / (
theta
** (torch.arange(0, dim, 2, device=device)[: (dim // 2)].to(dtype) / dim).to(
device=device
)
) # [D/2]
freqs = torch.outer(pos * interpolation_factor, freqs) # [S, D/2]
freqs_cos = freqs.cos() # [S, D/2]
freqs_sin = freqs.sin() # [S, D/2]
return freqs_cos, freqs_sin
class OneDRotaryEmbedding(torch.nn.Module):
"""1D rotary positional embedding with caching."""
def __init__(
self,
dim: int,
theta: float = 10000.0,
theta_rescale_factor: float = 1.0,
interpolation_factor: float = 1.0,
dtype: torch.dtype = torch.float32,
use_real: bool = False,
repeat_interleave_real: bool = False,
):
super().__init__()
assert dim % 2 == 0
self.dim = dim
self.theta = theta
self.theta_rescale_factor = theta_rescale_factor
self.interpolation_factor = interpolation_factor
# dtype of freqs
self.dtype = dtype
self.use_real = use_real
self.repeat_interleave_real = repeat_interleave_real
def build_freqs(self, device):
freqs = 1.0 / (
self.theta
** (
torch.arange(0, self.dim, 2, dtype=self.dtype, device=device)[
: (self.dim // 2)
]
/ self.dim
).to(device=device)
)
return freqs
def build_freqs_outer(self, pos: torch.Tensor, device):
theta = self.theta
# proposed by reddit user bloc97, to rescale rotary embeddings to longer sequence length without fine-tuning
# has some connection to NTK literature
if self.theta_rescale_factor != 1.0:
theta *= self.theta_rescale_factor ** (self.dim / (self.dim - 2))
freqs = self.build_freqs(device)
freqs = torch.outer(pos * self.interpolation_factor, freqs)
freqs_cos = freqs.cos()
freqs_sin = freqs.sin()
if self.use_real and self.repeat_interleave_real:
freqs_cos = freqs_cos.repeat_interleave(2, dim=1)
freqs_sin = freqs_sin.repeat_interleave(2, dim=1)
return freqs_cos.float(), freqs_sin.float()
@functools.lru_cache(maxsize=16)
def forward_from_grid(
self, seq_len: int, start_pos: int, device_str: str
) -> tuple[torch.Tensor, torch.Tensor]:
device = torch.device(device_str)
pos = torch.arange(
start_pos, start_pos + seq_len, dtype=self.dtype, device=device
)
freqs_cos, freqs_sin = self.build_freqs_outer(pos, device)
return freqs_cos, freqs_sin
def forward(self, pos: torch.Tensor) -> tuple[torch.Tensor, torch.Tensor]:
"""
Calculates 1D rotary embeddings for the given positions.
This method converts the input tensor to a hashable representation
and calls a cached helper method to perform the computation.
"""
pos_tuple = tuple(pos.tolist())
device_str = str(pos.device)
return self._forward_cached(pos_tuple, device_str)
@functools.lru_cache(maxsize=16)
def _forward_cached(
self, pos_tuple: tuple, device_str: str
) -> tuple[torch.Tensor, torch.Tensor]:
"""
The core implementation that computes 1D rotary embeddings.
This method is wrapped by an LRU cache.
"""
device = torch.device(device_str)
pos = torch.as_tensor(pos_tuple, dtype=self.dtype, device=device)
freqs_cos, freqs_sin = self.build_freqs_outer(pos, device)
return freqs_cos, freqs_sin
class NDRotaryEmbedding(torch.nn.Module):
"""N-dimensional rotary positional embedding."""
def __init__(
self,
rope_dim_list: list[int],
rope_theta: float,
theta_rescale_factor: float | list[float] = 1.0,
interpolation_factor: float | list[float] = 1.0,
use_real: bool = False,
repeat_interleave_real: bool = False,
dtype: torch.dtype = torch.float32,
):
super().__init__()
self.rope_dim_list = rope_dim_list
self.ndim = len(rope_dim_list)
self.rope_theta = rope_theta
# dtype of freqs
# does not control the output dtype
self.dtype = dtype
if isinstance(theta_rescale_factor, (int, float)):
self.theta_rescale_factor = [theta_rescale_factor] * self.ndim
elif isinstance(theta_rescale_factor, list) and len(theta_rescale_factor) == 1:
self.theta_rescale_factor = [theta_rescale_factor[0]] * self.ndim
else:
self.theta_rescale_factor = theta_rescale_factor
assert (
len(self.theta_rescale_factor) == self.ndim
), "len(theta_rescale_factor) should equal to len(rope_dim_list)"
if isinstance(interpolation_factor, (int, float)):
self.interpolation_factor = [interpolation_factor] * self.ndim
elif isinstance(interpolation_factor, list) and len(interpolation_factor) == 1:
self.interpolation_factor = [interpolation_factor[0]] * self.ndim
else:
self.interpolation_factor = interpolation_factor
assert (
len(self.interpolation_factor) == self.ndim
), "len(interpolation_factor) should equal to len(rope_dim_list)"
self.rope_generators: list[OneDRotaryEmbedding] = torch.nn.ModuleList()
_config_to_gen_idx: dict[tuple, int] = {}
self.dim_idx_to_gen_idx: list[int] = []
for i in range(self.ndim):
dim = self.rope_dim_list[i]
rescale = self.theta_rescale_factor[i]
interp = self.interpolation_factor[i]
config_key = (dim, rescale, interp, use_real, repeat_interleave_real)
if config_key not in _config_to_gen_idx:
generator = OneDRotaryEmbedding(
dim=dim,
theta=self.rope_theta,
theta_rescale_factor=rescale,
interpolation_factor=interp,
dtype=self.dtype,
use_real=use_real,
repeat_interleave_real=repeat_interleave_real,
)
_config_to_gen_idx[config_key] = len(self.rope_generators)
self.rope_generators.append(generator)
gen_idx = _config_to_gen_idx[config_key]
self.dim_idx_to_gen_idx.append(gen_idx)
def forward(self, positions: torch.Tensor) -> tuple[torch.Tensor, torch.Tensor]:
"""
Calculates n-d rotary embeddings for given absolute positions.
Args:
positions (torch.Tensor): A tensor of shape `[num_tokens, ndim]`
containing the integer coordinates for each token.
Returns:
A tuple of (cos, sin) tensors.
"""
# Caching wrapper: convert tensor to a hashable tuple of tuples.
pos_tuple = tuple(map(tuple, positions.tolist()))
device_str = str(positions.device)
return self._forward_cached(pos_tuple, device_str)
@functools.lru_cache(maxsize=16)
def _forward_cached(
self, pos_tuple: tuple[tuple[int, ...], ...], device_str: str
) -> tuple[torch.Tensor, torch.Tensor]:
"""
The core implementation that computes embeddings from a position tensor.
This method is wrapped by an LRU cache.
"""
device = torch.device(device_str)
positions = torch.tensor(pos_tuple, dtype=torch.long, device=device)
return self.forward_uncached(pos=positions)
def forward_uncached(self, pos: torch.Tensor) -> tuple[torch.Tensor, torch.Tensor]:
"""
The core implementation that computes embeddings from a position tensor.
This method is wrapped by an LRU cache.
"""
device = pos.device
# Pre-allocate the final tensors for efficiency.
num_tokens = pos.shape[0]
first_generator = self.rope_generators[0]
if first_generator.use_real and first_generator.repeat_interleave_real:
head_dim = sum(self.rope_dim_list)
else:
head_dim = sum(self.rope_dim_list) // 2
cos = torch.empty((num_tokens, head_dim), device=device, dtype=self.dtype)
sin = torch.empty((num_tokens, head_dim), device=device, dtype=self.dtype)
col_offset = 0
for i in range(self.ndim):
# Extract position coordinates for the current dimension for all tokens.
pos_i = pos[:, i].to(self.dtype)
# Get the appropriate 1D generator.
gen_idx = self.dim_idx_to_gen_idx[i]
generator = self.rope_generators[gen_idx]
# Calculate 1D embeddings.
cos_1d, sin_1d = generator(pos_i)
slice_width = cos_1d.shape[1]
cos[:, col_offset : col_offset + slice_width] = cos_1d
sin[:, col_offset : col_offset + slice_width] = sin_1d
col_offset += slice_width
return cos.float(), sin.float()
def forward_from_grid(
self,
grid_size: tuple[int, ...],
shard_dim: int = 0,
start_frame: int = 0,
device: torch.device | str | None = None,
) -> tuple[torch.Tensor, torch.Tensor]:
"""
Handles sp internally
"""
# Caching wrapper: use grid parameters directly as the key.
# grid_tuple = _to_tuple(grid_size, dim=self.ndim)
device_str = str(device) if device is not None else "cpu"
return self._forward_cached_from_grid(
grid_size, shard_dim, start_frame, device_str
)
@functools.lru_cache(maxsize=16)
def _forward_cached_from_grid(
self,
grid_size: tuple[int, ...],
shard_dim: int,
start_frame: int,
device_str: str,
) -> tuple[torch.Tensor, torch.Tensor]:
"""
Computes embeddings for a structured grid, using a highly efficient
implementation that avoids materializing the full position tensor.
This method is wrapped by an LRU cache.
"""
device = torch.device(device_str)
sp_group = get_sp_group()
sp_rank = sp_group.rank_in_group
sp_world_size = sp_group.world_size
sizes = _to_tuple(grid_size, dim=self.ndim)
starts = (0,) * self.ndim
# Apply sequence parallel sharding to the sizes and compute shard offset
shard_sizes = list(sizes)
shard_offsets = [0] * self.ndim
if sp_world_size > 1:
assert sizes[shard_dim] % sp_world_size == 0, (
f"Dimension {shard_dim} with size {sizes[shard_dim]} is not divisible "
f"by sequence parallel world size {sp_world_size}"
)
shard_size = sizes[shard_dim] // sp_world_size
shard_offsets[shard_dim] = sp_rank * shard_size
shard_sizes[shard_dim] = shard_size
# Pre-allocate outputs on the requested device to avoid CPU ops and extra cats
num_tokens = 1
for s in shard_sizes:
num_tokens *= int(s)
head_dim_half = sum(self.rope_dim_list) // 2
cos = torch.empty((num_tokens, head_dim_half), device=device, dtype=self.dtype)
sin = torch.empty((num_tokens, head_dim_half), device=device, dtype=self.dtype)
# Compute per-axis 1D embeddings once and expand via repeats to [N, d_i/2]
col_offset = 0
for i in range(self.ndim):
dim_i = self.rope_dim_list[i]
dim_i_half = dim_i // 2
size_i = int(shard_sizes[i])
# Starting position for this axis, with optional frame offset for time axis (i==0)
base_offset = starts[i]
if i == 0 and start_frame > 0:
base_offset += start_frame
if sp_world_size > 1 and i == shard_dim:
base_offset += shard_offsets[i]
gen_idx = self.dim_idx_to_gen_idx[i]
generator = self.rope_generators[gen_idx]
cos_1d, sin_1d = generator.forward_from_grid(
size_i, base_offset, device_str
)
# Expand to [num_tokens, dim_i/2] matching flatten order (last dims vary fastest)
repeats_per_entry = 1
for j in range(i + 1, self.ndim):
repeats_per_entry *= int(shard_sizes[j])
tile_count = 1
for j in range(0, i):
tile_count *= int(shard_sizes[j])
cos_expanded = cos_1d.repeat_interleave(repeats_per_entry, dim=0)
sin_expanded = sin_1d.repeat_interleave(repeats_per_entry, dim=0)
if tile_count > 1:
cos_expanded = cos_expanded.repeat(tile_count, 1)
sin_expanded = sin_expanded.repeat(tile_count, 1)
cos[:, col_offset : col_offset + dim_i_half] = cos_expanded
sin[:, col_offset : col_offset + dim_i_half] = sin_expanded
col_offset += dim_i_half
return cos.float(), sin.float()

View File

@@ -0,0 +1,121 @@
"""Primitive RoPE ops: rotate helpers and apply_rotary_emb utilities."""
from typing import Optional, Tuple
import torch
from sglang.jit_kernel.diffusion.triton.rotary import apply_rotary_embedding
def _apply_rotary_emb(
x: torch.Tensor,
cos: torch.Tensor,
sin: torch.Tensor,
is_neox_style: bool,
interleaved: bool = False,
) -> torch.Tensor:
"""
Args:
x: [num_tokens, num_heads, head_size] or [num_tokens, head_size]
cos: [num_tokens, head_size // 2]
sin: [num_tokens, head_size // 2]
is_neox_style: Whether to use the Neox-style or GPT-J-style rotary
positional embeddings.
"""
# cos = cos.unsqueeze(-2).to(x.dtype)
# sin = sin.unsqueeze(-2).to(x.dtype)
if is_neox_style:
cos = cos.unsqueeze(-2)
sin = sin.unsqueeze(-2)
if is_neox_style:
x1, x2 = torch.chunk(x, 2, dim=-1)
else:
x1 = x[..., ::2]
x2 = x[..., 1::2]
o1 = (x1.float() * cos - x2.float() * sin).type_as(x)
o2 = (x2.float() * cos + x1.float() * sin).type_as(x)
return torch.cat((o1, o2), dim=-1)
else:
return apply_rotary_embedding(x, cos, sin, interleaved)
def apply_flashinfer_rope_qk_inplace(
q: torch.Tensor,
k: torch.Tensor,
cos_sin_cache: torch.Tensor,
*,
head_size: Optional[int] = None,
is_neox: bool = False,
positions: Optional[torch.Tensor] = None,
) -> Tuple[torch.Tensor, torch.Tensor]:
if q.dim() != 4 or k.dim() != 4:
raise ValueError(
f"Expected q/k to be 4D [bsz, seqlen, nheads, head_size], "
f"got q:{tuple(q.shape)} k:{tuple(k.shape)}"
)
if q.shape != k.shape:
raise ValueError(
f"q and k must have the same shape, got {q.shape} vs {k.shape}"
)
if not (isinstance(cos_sin_cache, torch.Tensor) and cos_sin_cache.dim() == 2):
raise ValueError("cos_sin_cache must be a 2D torch.Tensor")
bsz, seqlen, nheads, d = q.shape
if head_size is None:
head_size = d
if head_size != d:
raise ValueError(f"head_size mismatch: inferred {d}, but head_size={head_size}")
try:
from flashinfer.rope import apply_rope_with_cos_sin_cache_inplace
except ImportError:
# Triton fallback for AMD/ROCm where FlashInfer is not available
import warnings
warnings.warn(
"FlashInfer not available, using Triton fallback for RoPE",
stacklevel=2,
)
half_size = cos_sin_cache.shape[-1] // 2
if positions is None:
cos = cos_sin_cache[:seqlen, :half_size].to(q.dtype)
sin = cos_sin_cache[:seqlen, half_size:].to(q.dtype)
cos = cos.unsqueeze(0).expand(bsz, -1, -1).reshape(bsz * seqlen, -1)
sin = sin.unsqueeze(0).expand(bsz, -1, -1).reshape(bsz * seqlen, -1)
else:
positions = positions.to(cos_sin_cache.device).view(-1)
cos = cos_sin_cache[positions, :half_size].to(q.dtype)
sin = cos_sin_cache[positions, half_size:].to(q.dtype)
q_flat = q.reshape(bsz * seqlen, nheads, d)
k_flat = k.reshape(bsz * seqlen, nheads, d)
q_rot = apply_rotary_embedding(q_flat, cos, sin, interleaved=not is_neox)
k_rot = apply_rotary_embedding(k_flat, cos, sin, interleaved=not is_neox)
return q_rot.view(bsz, seqlen, nheads, d), k_rot.view(bsz, seqlen, nheads, d)
if positions is None:
pos_1d = torch.arange(seqlen, device=q.device, dtype=torch.long)
positions = pos_1d if bsz == 1 else pos_1d.repeat(bsz)
else:
if not (
isinstance(positions, torch.Tensor)
and positions.dtype == torch.long
and positions.dim() == 1
):
raise ValueError("positions must be a 1D torch.long Tensor")
if positions.numel() != bsz * seqlen:
raise ValueError(
f"positions length must be bsz*seqlen={bsz*seqlen}, got {positions.numel()}"
)
q_flat = q.reshape(bsz * seqlen, nheads * d).contiguous()
k_flat = k.reshape(bsz * seqlen, nheads * d).contiguous()
apply_rope_with_cos_sin_cache_inplace(
positions=positions,
query=q_flat,
key=k_flat,
head_size=d,
cos_sin_cache=cos_sin_cache,
is_neox=is_neox,
)
return q_flat.view(bsz, seqlen, nheads, d), k_flat.view(bsz, seqlen, nheads, d)