[NPU]LoRA: Adding Torch Native backend (#14132)

This commit is contained in:
Vladimir Serov
2025-12-07 21:16:07 +03:00
committed by GitHub
parent c8683ae305
commit f124539a01
8 changed files with 979 additions and 16 deletions

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@@ -1,5 +1,3 @@
from typing import Optional
import torch
from sglang.srt.lora.backend.base_backend import BaseLoRABackend
@@ -204,16 +202,33 @@ class AscendLoRABackend(BaseLoRABackend):
return output_tensor
def init_cuda_graph_batch_info(
self, cuda_graph_batch_info: LoRABatchInfo, max_bs_in_cuda_graph: int
self,
max_bs_in_cuda_graph: int,
num_tokens_per_bs: int,
):
# Initialize seg_lens and seg_indptr for CUDA graph as they remain constant
# across batches.
cuda_graph_batch_info.seg_lens[:max_bs_in_cuda_graph].fill_(1)
torch.cumsum(
cuda_graph_batch_info.seg_lens[:max_bs_in_cuda_graph],
dim=0,
out=cuda_graph_batch_info.seg_indptr[1 : max_bs_in_cuda_graph + 1],
)
with torch.device("npu"):
self.npu_graph_batch_info = LoRABatchInfo(
bs=max_bs_in_cuda_graph,
use_cuda_graph=True,
num_segments=None,
seg_lens=torch.full(
(max_bs_in_cuda_graph,), num_tokens_per_bs, dtype=torch.int32
),
seg_indptr=torch.empty(max_bs_in_cuda_graph + 1, dtype=torch.int32),
max_len=num_tokens_per_bs,
weight_indices=torch.zeros(max_bs_in_cuda_graph, dtype=torch.int32),
lora_ranks=torch.zeros(self.max_loras_per_batch, dtype=torch.int32),
scalings=torch.zeros(self.max_loras_per_batch, dtype=torch.float),
permutation=None,
)
# Initialize seg_indptr for NPU graph as they remain constant
# across batches.
torch.cumsum(
self.npu_graph_batch_info.seg_lens[:max_bs_in_cuda_graph],
dim=0,
out=self.npu_graph_batch_info.seg_indptr[1 : max_bs_in_cuda_graph + 1],
)
def prepare_lora_batch(
self,
@@ -221,7 +236,7 @@ class AscendLoRABackend(BaseLoRABackend):
weight_indices: list[int],
lora_ranks: list[int],
scalings: list[float],
batch_info: Optional[LoRABatchInfo] = None,
use_cuda_graph: bool,
):
# Use pinned memory to avoid synchronizations during host-to-device transfer
weight_indices_tensor = torch.tensor(
@@ -236,10 +251,11 @@ class AscendLoRABackend(BaseLoRABackend):
bs = forward_batch.batch_size
if batch_info is not None:
if use_cuda_graph:
assert (
batch_info.use_cuda_graph
), "batch_info.use_cuda_graph must be True when batch_info is provided"
self.npu_graph_batch_info is not None
), "NPU Graph batch info is not initialized."
batch_info = self.npu_graph_batch_info
batch_info.bs = forward_batch.batch_size
batch_info.num_segments = forward_batch.batch_size
else:

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@@ -36,6 +36,13 @@ def create_ascend_backend():
return AscendLoRABackend
@register_lora_backend("torch_native")
def create_torch_native_backend():
from sglang.srt.lora.backend.torch_backend import TorchNativeLoRABackend
return TorchNativeLoRABackend
@register_lora_backend("flashinfer")
def create_flashinfer_backend():
raise ValueError(

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@@ -0,0 +1,297 @@
import torch
from sglang.srt.lora.backend.base_backend import BaseLoRABackend
from sglang.srt.lora.torch_ops import sgmv_expand, sgmv_expand_slice, sgmv_shrink
from sglang.srt.lora.utils import LoRABatchInfo
from sglang.srt.model_executor.forward_batch_info import ForwardBatch
class TorchNativeLoRABackend(BaseLoRABackend):
name = "torch_native"
def __init__(
self,
max_loras_per_batch: int,
device: torch.device,
**kwargs,
):
super().__init__(max_loras_per_batch, device)
def run_lora_a_sgemm(
self, x: torch.Tensor, weights: torch.Tensor, *args, **kwargs
) -> torch.Tensor:
total_seq_len, _ = x.shape
_, weight_out_dim, _ = weights.shape
output_tensor = torch.zeros(
(total_seq_len, weight_out_dim), dtype=x.dtype, device=x.device
)
sgmv_shrink(
x,
weights,
output_tensor,
self.batch_info.seg_lens,
self.batch_info.weight_indices,
1.0,
)
scaling = torch.repeat_interleave(
self.batch_info.scalings[self.batch_info.weight_indices],
self.batch_info.seg_lens,
output_size=total_seq_len,
).unsqueeze(-1)
output_tensor = output_tensor * scaling
return output_tensor
def run_lora_b_sgemm(
self,
x: torch.Tensor,
weights: torch.Tensor,
base_output: torch.Tensor = None,
*args,
**kwargs,
) -> torch.Tensor:
total_seq_len, _ = x.shape
_, weight_out_dim, _ = weights.shape
if base_output is None:
output_tensor = torch.zeros(
(total_seq_len, weight_out_dim), device=x.device, dtype=x.dtype
)
else:
output_tensor = base_output
sgmv_expand(
x,
weights,
output_tensor,
self.batch_info.seg_lens,
self.batch_info.weight_indices,
True,
)
return output_tensor
def run_qkv_lora(
self,
x: torch.Tensor,
qkv_lora_a: torch.Tensor,
qkv_lora_b: torch.Tensor,
output_offset: torch.Tensor,
output_offset_cpu: torch.Tensor,
max_qkv_out_dim: int,
base_output: torch.Tensor = None,
*args,
**kwargs,
) -> torch.Tensor:
num_slices = 3
assert isinstance(qkv_lora_b, torch.Tensor)
total_seq_len, _ = x.shape
_, weight_intermediate_dim, _ = qkv_lora_a.shape
_, weight_out_dim, _ = qkv_lora_b.shape
max_rank = weight_intermediate_dim // num_slices
if base_output is None:
output_tensor = torch.zeros(
(total_seq_len, weight_out_dim), device=x.device, dtype=x.dtype
)
else:
output_tensor = base_output
lora_a_output = torch.zeros(
total_seq_len, weight_intermediate_dim, dtype=x.dtype, device=x.device
)
sgmv_shrink(
x,
qkv_lora_a,
lora_a_output,
self.batch_info.seg_lens,
self.batch_info.weight_indices,
1.0,
)
scaling = torch.repeat_interleave(
self.batch_info.scalings[self.batch_info.weight_indices],
self.batch_info.seg_lens,
output_size=total_seq_len,
).unsqueeze(-1)
lora_a_output = lora_a_output * scaling
for slice_id in range(num_slices):
slice_offset = output_offset_cpu[slice_id]
slice_offset_next = output_offset_cpu[slice_id + 1]
slice_size = slice_offset_next - slice_offset
sgmv_expand_slice(
lora_a_output[:, (max_rank * slice_id) : (max_rank * (slice_id + 1))],
qkv_lora_b[:, slice_offset:slice_offset_next],
output_tensor,
self.batch_info.seg_lens,
self.batch_info.weight_indices,
slice_offset,
slice_size,
True,
)
return output_tensor
def run_gate_up_lora(
self,
x: torch.Tensor,
gate_up_lora_a: torch.Tensor,
gate_up_lora_b: torch.Tensor,
base_output: torch.Tensor = None,
*args,
**kwargs,
) -> torch.Tensor:
num_slices = 2
assert isinstance(gate_up_lora_b, torch.Tensor)
total_seq_len, _ = x.shape
_, weight_intermediate_dim, _ = gate_up_lora_a.shape
_, weight_out_dim, _ = gate_up_lora_b.shape
slice_size = weight_out_dim // num_slices
max_rank = weight_intermediate_dim // num_slices
if base_output is None:
output_tensor = torch.zeros(
(total_seq_len, weight_out_dim), device=x.device, dtype=x.dtype
)
else:
output_tensor = base_output
lora_a_output = torch.zeros(
total_seq_len, weight_intermediate_dim, dtype=x.dtype, device=x.device
)
sgmv_shrink(
x,
gate_up_lora_a,
lora_a_output,
self.batch_info.seg_lens,
self.batch_info.weight_indices,
1.0,
)
scaling = torch.repeat_interleave(
self.batch_info.scalings[self.batch_info.weight_indices],
self.batch_info.seg_lens,
output_size=total_seq_len,
).unsqueeze(-1)
lora_a_output = lora_a_output * scaling
slice_offset = 0
for slice_id in range(num_slices):
sgmv_expand_slice(
lora_a_output[:, (max_rank * slice_id) : (max_rank * (slice_id + 1))],
gate_up_lora_b[:, slice_offset : slice_offset + slice_size],
output_tensor,
self.batch_info.seg_lens,
self.batch_info.weight_indices,
slice_offset,
slice_size,
True,
)
slice_offset += slice_size
return output_tensor
def init_cuda_graph_batch_info(
self,
max_bs_in_cuda_graph: int,
num_tokens_per_bs: int,
):
with torch.device("cuda"):
self.cuda_graph_batch_info = LoRABatchInfo(
bs=max_bs_in_cuda_graph,
use_cuda_graph=True,
num_segments=None,
seg_lens=torch.full(
(max_bs_in_cuda_graph,), num_tokens_per_bs, dtype=torch.int32
),
seg_indptr=torch.empty(max_bs_in_cuda_graph + 1, dtype=torch.int32),
max_len=num_tokens_per_bs,
weight_indices=torch.zeros(max_bs_in_cuda_graph, dtype=torch.int32),
lora_ranks=torch.zeros(self.max_loras_per_batch, dtype=torch.int32),
scalings=torch.zeros(self.max_loras_per_batch, dtype=torch.float),
permutation=None,
)
# Initialize seg_indptr for CUDA graph as they remain constant
# across batches.
torch.cumsum(
self.cuda_graph_batch_info.seg_lens[:max_bs_in_cuda_graph],
dim=0,
out=self.cuda_graph_batch_info.seg_indptr[1 : max_bs_in_cuda_graph + 1],
)
def prepare_lora_batch(
self,
forward_batch: ForwardBatch,
weight_indices: list[int],
lora_ranks: list[int],
scalings: list[float],
use_cuda_graph: bool,
):
# Use pinned memory to avoid synchronizations during host-to-device transfer
weight_indices_tensor = torch.tensor(
weight_indices, dtype=torch.int32, pin_memory=True, device="cpu"
)
lora_ranks_tensor = torch.tensor(
lora_ranks, dtype=torch.int32, pin_memory=True, device="cpu"
)
scalings_tensor = torch.tensor(
scalings, dtype=torch.float, pin_memory=True, device="cpu"
)
bs = forward_batch.batch_size
if use_cuda_graph:
assert (
self.cuda_graph_batch_info is not None
), "CUDA Graph batch info is not initialized."
batch_info = self.cuda_graph_batch_info
batch_info.bs = forward_batch.batch_size
batch_info.num_segments = forward_batch.batch_size
else:
max_len = (
# Calculate max_len from the CPU copy to avoid D2H transfer.
max(forward_batch.extend_seq_lens_cpu)
if forward_batch.forward_mode.is_extend()
else 1
)
seg_lens = (
forward_batch.extend_seq_lens
if forward_batch.forward_mode.is_extend()
else torch.ones(bs, dtype=torch.int32, device=self.device)
)
seg_indptr = torch.zeros((bs + 1,), dtype=torch.int32, device=self.device)
seg_indptr[1:] = torch.cumsum(seg_lens, dim=0)
batch_info = LoRABatchInfo(
bs=forward_batch.batch_size,
num_segments=forward_batch.batch_size,
max_len=max_len,
use_cuda_graph=False,
seg_lens=seg_lens,
seg_indptr=seg_indptr,
weight_indices=torch.empty(
(bs,), dtype=torch.int32, device=self.device
),
lora_ranks=torch.empty(
(self.max_loras_per_batch,), dtype=torch.int32, device=self.device
),
scalings=torch.empty(
(self.max_loras_per_batch,), dtype=torch.float, device=self.device
),
permutation=None,
)
# Copy to device asynchronously
batch_info.lora_ranks[: self.max_loras_per_batch].copy_(
lora_ranks_tensor, non_blocking=True
)
batch_info.scalings[: self.max_loras_per_batch].copy_(
scalings_tensor, non_blocking=True
)
batch_info.weight_indices[:bs].copy_(weight_indices_tensor, non_blocking=True)
self.batch_info = batch_info

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@@ -0,0 +1,7 @@
from .lora_ops import sgmv_expand, sgmv_expand_slice, sgmv_shrink
__all__ = [
"sgmv_expand",
"sgmv_expand_slice",
"sgmv_shrink",
]

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@@ -0,0 +1,125 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import torch
def sgmv_expand(
inputs: torch.Tensor,
lora_b_weights: torch.Tensor,
output_tensor: torch.Tensor,
seq_len_tensor: torch.Tensor,
lora_indices_tensor: torch.Tensor,
add_inputs: bool = False,
):
total_seq_len, _ = inputs.shape
exploded_indices = torch.repeat_interleave(
lora_indices_tensor, seq_len_tensor, output_size=total_seq_len
)
bgmv_expand(inputs, lora_b_weights, output_tensor, exploded_indices, add_inputs)
def bgmv_expand(
inputs: torch.Tensor,
lora_b_weights: torch.Tensor,
output_tensor: torch.Tensor,
lora_indices_tensor: torch.Tensor,
add_inputs: bool = True,
):
selected_loras = lora_b_weights[lora_indices_tensor].to(dtype=output_tensor.dtype)
if len(selected_loras.shape) == 4:
selected_loras = selected_loras.squeeze(dim=1)
inputs = inputs.to(dtype=output_tensor.dtype)
outputs = torch.einsum("bi, boi -> bo", inputs, selected_loras)
limit = output_tensor.shape[0]
if outputs.shape[0] == 1 and output_tensor.shape[0] != 1:
limit = 1
# LoRA adapter and model may add different amounts of padding to output
common_len = min(outputs.shape[1], output_tensor.shape[1])
if add_inputs:
output_tensor[:, :common_len] += outputs[:limit, :common_len]
else:
output_tensor[:, :common_len] = outputs[:limit, :common_len]
def sgmv_shrink(
inputs: torch.Tensor,
lora_a_weights: torch.Tensor,
output_tensor: torch.Tensor,
seq_len_tensor: torch.Tensor,
lora_indices_tensor: torch.Tensor,
scaling: float,
):
total_seq_len, _ = inputs.shape
exploded_indices = torch.repeat_interleave(
lora_indices_tensor, seq_len_tensor, output_size=total_seq_len
)
bgmv_shrink(inputs, lora_a_weights, output_tensor, exploded_indices, scaling)
def bgmv_shrink(
inputs: torch.Tensor,
lora_a_weights: torch.Tensor,
output_tensor: torch.Tensor,
lora_indices_tensor: torch.Tensor,
scaling: float = 1.0,
):
selected_loras = lora_a_weights[lora_indices_tensor].to(dtype=output_tensor.dtype)
if len(selected_loras.shape) == 4:
selected_loras = selected_loras.squeeze(dim=1)
inputs = inputs.to(dtype=output_tensor.dtype)
outputs = torch.einsum("bi, boi -> bo", inputs, selected_loras)
output_tensor[:, : outputs.shape[1]] = scaling * outputs[:]
def sgmv_expand_slice(
inputs: torch.Tensor,
lora_b_weights: torch.Tensor,
output_tensor: torch.Tensor,
seq_len_tensor: torch.Tensor,
lora_indices_tensor: torch.Tensor,
slice_offset: int,
slice_size: int,
add_inputs: bool = False,
):
total_seq_len, _ = inputs.shape
exploded_indices = torch.repeat_interleave(
lora_indices_tensor, seq_len_tensor, output_size=total_seq_len
)
bgmv_expand_slice(
inputs,
lora_b_weights,
output_tensor,
exploded_indices,
slice_offset,
slice_size,
add_inputs,
)
def bgmv_expand_slice(
inputs: torch.Tensor,
lora_b_weights: torch.Tensor,
output_tensor: torch.Tensor,
lora_indices_tensor: torch.Tensor,
slice_offset: int,
slice_size: int,
add_inputs: bool = True,
):
selected_loras = lora_b_weights[lora_indices_tensor].to(dtype=output_tensor.dtype)
inputs = inputs.to(dtype=output_tensor.dtype)
if len(selected_loras.shape) == 4:
selected_loras = selected_loras.squeeze(dim=1)
outputs = torch.einsum("bi, boi -> bo", inputs, selected_loras)
if add_inputs:
output_tensor[:, slice_offset : slice_offset + slice_size] += outputs[:]
else:
output_tensor[:, slice_offset : slice_offset + slice_size] = outputs[:]

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@@ -131,7 +131,7 @@ ATTENTION_BACKEND_CHOICES = [
"intel_xpu",
]
LORA_BACKEND_CHOICES = ["triton", "csgmv", "ascend"]
LORA_BACKEND_CHOICES = ["triton", "csgmv", "ascend", "torch_native"]
DISAGG_TRANSFER_BACKEND_CHOICES = ["mooncake", "nixl", "ascend", "fake"]