sglang_v0.5.2/flashinfer_0.3.1/flashinfer/cudnn/prefill.py

542 lines
20 KiB
Python

from enum import Enum
from typing import Optional
import torch
from ..jit import get_cudnn_fmha_gen_module
try:
import cudnn
CUDNN_AVAILABLE = True
except Exception:
cudnn = None
CUDNN_AVAILABLE = False
# Global cudnn handle. need to make it per device in future
_cudnn_handle = None
def _create_cudnn_handle(stream: torch.cuda.Stream):
global _cudnn_handle
if _cudnn_handle is None:
_cudnn_handle = cudnn.create_handle()
cudnn.set_stream(_cudnn_handle, stream.cuda_stream)
return _cudnn_handle
# Tensor ids
class UIDs(Enum):
RESERVED_INVALID_UID = 0
Q_UID = 1 # Query tensor
K_UID = 2 # Key cache tensor
V_UID = 3 # Value cache tensor
ACTUAL_SEQ_LENS_Q_UID = 100 # Actual sequence lengths for query tensor
ACTUAL_SEQ_LENS_KV_UID = 101 # Actual sequence lengths for key/value tensor
BLOCK_TABLES_UID = 200 # Block tables tensor
BLOCK_TABLES_K_UID = 201 # Block tables tensor for key
BLOCK_TABLES_V_UID = 202 # Block tables tensor for value
RAGGED_Q_UID = 50 # Ragged query tensor
RAGGED_O_UID = 51 # Ragged output tensor
RAGGED_STATS_UID = 52 # Ragged stats tensor
RAGGED_K_UID = 53 # Ragged key tensor
RAGGED_V_UID = 54 # Ragged value tensor
O_UID = 1000 # Output tensor
STATS_UID = 1001 # Stats tensor
def _sdpa_prefill_key_fn(
q: torch.Tensor,
k_cache: torch.Tensor,
v_cache: torch.Tensor,
scale: float,
*,
max_token_seq_q: Optional[int] = None,
max_sequence_kv: Optional[int] = None,
actual_seq_lens_q: Optional[torch.Tensor] = None,
actual_seq_lens_kv: torch.Tensor,
block_tables: Optional[torch.Tensor] = None,
page_size: Optional[int] = None,
bottom_right_causal_mask: Optional[bool] = None,
return_lse: Optional[bool] = False,
batch_offsets_q: Optional[torch.Tensor] = None,
batch_offsets_o: Optional[torch.Tensor] = None,
batch_offsets_k: Optional[torch.Tensor] = None,
batch_offsets_v: Optional[torch.Tensor] = None,
batch_offsets_stats: Optional[torch.Tensor] = None,
out: Optional[torch.Tensor] = None,
lse: Optional[torch.Tensor] = None,
):
graph_b = actual_seq_lens_q.shape[0]
if q.dim() == 3:
h_qo, d_qk = q.shape[1], q.shape[2]
elif q.dim() == 4:
h_qo, d_qk = q.shape[1], q.shape[3]
if v_cache.dim() == 3:
h_kv, d_vo = k_cache.shape[1], k_cache.shape[2]
elif k_cache.dim() == 4:
h_kv, d_vo = k_cache.shape[1], k_cache.shape[3]
if block_tables is not None:
page_size = k_cache.shape[2]
key = (
graph_b,
q.dim(),
k_cache.dim(),
max_token_seq_q,
max_sequence_kv,
h_qo,
d_qk,
h_kv,
d_vo,
block_tables is not None,
return_lse,
bottom_right_causal_mask,
page_size,
)
return key
if CUDNN_AVAILABLE:
@cudnn.jit(heur_modes=[cudnn.heur_mode.A])
@cudnn.graph_cache(key_fn=_sdpa_prefill_key_fn)
def _build_prefill_graph(
q: torch.Tensor,
k_cache: torch.Tensor,
v_cache: torch.Tensor,
scale: float,
*,
max_token_seq_q: Optional[int] = None,
max_sequence_kv: Optional[int] = None,
actual_seq_lens_q: Optional[torch.Tensor] = None,
actual_seq_lens_kv: Optional[torch.Tensor] = None,
block_tables: Optional[torch.Tensor] = None,
bottom_right_causal_mask: Optional[bool] = True,
return_lse: Optional[bool] = False,
batch_offsets_q: Optional[torch.Tensor] = None,
batch_offsets_o: Optional[torch.Tensor] = None,
batch_offsets_k: Optional[torch.Tensor] = None,
batch_offsets_v: Optional[torch.Tensor] = None,
batch_offsets_stats: Optional[torch.Tensor] = None,
out: Optional[torch.Tensor] = None,
lse: Optional[torch.Tensor] = None,
):
handle = _create_cudnn_handle(torch.cuda.current_stream(q.device))
graph_b = actual_seq_lens_q.shape[0]
graph_s_qo = max_token_seq_q
graph_s_kv = max_sequence_kv
with cudnn.graph(handle) as (g, _):
# Create tensors from the input tensors
if q.dim() == 3:
h_qo, d_qk = q.shape[1], q.shape[2]
elif q.dim() == 4:
h_qo, d_qk = q.shape[2], q.shape[3]
else:
raise ValueError(f"Invalid query tensor shape: {q.shape}")
cudnn_q = g.tensor(
name="q",
dim=(graph_b, h_qo, graph_s_qo, d_qk),
stride=(h_qo * d_qk, d_qk, d_qk * h_qo, 1),
data_type=cudnn.data_type.BFLOAT16,
)
if batch_offsets_q is not None:
ragged_q = g.tensor_like(batch_offsets_q)
ragged_q.set_uid(UIDs.RAGGED_Q_UID.value)
cudnn_q.set_ragged_offset(ragged_q)
if v_cache.dim() == 3:
assert block_tables is None, (
"block_tables needs 4 dimensions of kv cache"
)
h_kv, d_vo = v_cache.shape[1], v_cache.shape[2]
elif v_cache.dim() == 4:
h_kv, d_vo = (
v_cache.shape[1],
v_cache.shape[3],
)
else:
raise ValueError(f"Invalid kv cache tensor shape: {k_cache.shape}")
if k_cache.dim() == 3:
cudnn_k_cache = g.tensor(
name="k_cache",
dim=(graph_b, h_kv, graph_s_kv, d_qk),
stride=(h_kv * d_qk * graph_s_kv, d_qk, d_qk * h_kv, 1),
data_type=cudnn.data_type.BFLOAT16,
)
if batch_offsets_k is not None:
ragged_k = g.tensor_like(batch_offsets_k)
ragged_k.set_uid(UIDs.RAGGED_K_UID.value)
cudnn_k_cache.set_ragged_offset(ragged_k)
cudnn_v_cache = g.tensor(
name="v_cache",
dim=(graph_b, h_kv, graph_s_kv, d_vo),
stride=(h_kv * d_vo * graph_s_kv, d_vo, d_vo * h_kv, 1),
data_type=cudnn.data_type.BFLOAT16,
)
if batch_offsets_v is not None:
ragged_v = g.tensor_like(batch_offsets_v)
ragged_v.set_uid(UIDs.RAGGED_V_UID.value)
cudnn_v_cache.set_ragged_offset(ragged_v)
elif k_cache.dim() == 4:
cudnn_k_cache = g.tensor(
name="k_cache",
dim=k_cache.shape,
stride=k_cache.stride(),
data_type=cudnn.data_type.BFLOAT16,
)
cudnn_v_cache = g.tensor(
name="v_cache",
dim=v_cache.shape,
stride=v_cache.stride(),
data_type=cudnn.data_type.BFLOAT16,
)
cudnn_q.set_uid(UIDs.Q_UID.value)
cudnn_k_cache.set_uid(UIDs.K_UID.value)
cudnn_v_cache.set_uid(UIDs.V_UID.value)
if block_tables is not None:
nd_block_tables = block_tables.reshape(
block_tables.shape[0], 1, block_tables.shape[1], 1
)
cudnn_k_block_tables = g.tensor_like(nd_block_tables)
cudnn_k_block_tables.set_uid(UIDs.BLOCK_TABLES_K_UID.value)
cudnn_v_block_tables = g.tensor_like(nd_block_tables)
cudnn_v_block_tables.set_uid(UIDs.BLOCK_TABLES_V_UID.value)
if actual_seq_lens_q is not None:
cudnn_actual_seq_lens_q = g.tensor_like(actual_seq_lens_q)
cudnn_actual_seq_lens_q.set_name("actual_seq_lens_q")
cudnn_actual_seq_lens_q.set_uid(UIDs.ACTUAL_SEQ_LENS_Q_UID.value)
if actual_seq_lens_kv is not None:
cudnn_actual_seq_lens_kv = g.tensor_like(actual_seq_lens_kv)
cudnn_actual_seq_lens_kv.set_name("actual_seq_lens_kv")
cudnn_actual_seq_lens_kv.set_uid(UIDs.ACTUAL_SEQ_LENS_KV_UID.value)
padding_mask = (
actual_seq_lens_q is not None and actual_seq_lens_kv is not None
)
O, Stats = g.sdpa(
name="sdpa",
q=cudnn_q,
k=cudnn_k_cache,
v=cudnn_v_cache,
seq_len_q=(
cudnn_actual_seq_lens_q if actual_seq_lens_q is not None else None
),
seq_len_kv=(
cudnn_actual_seq_lens_kv if actual_seq_lens_kv is not None else None
),
use_padding_mask=padding_mask,
attn_scale=scale,
generate_stats=return_lse,
use_causal_mask_bottom_right=bottom_right_causal_mask,
paged_attention_k_table=(
cudnn_k_block_tables if block_tables is not None else None
),
paged_attention_v_table=(
cudnn_v_block_tables if block_tables is not None else None
),
paged_attention_max_seq_len_kv=(
graph_s_kv if block_tables is not None else None
),
compute_data_type=cudnn.data_type.FLOAT,
)
if batch_offsets_o is not None:
ragged_o = g.tensor_like(batch_offsets_o)
ragged_o.set_uid(UIDs.RAGGED_O_UID.value)
O.set_ragged_offset(ragged_o)
if batch_offsets_stats is not None:
ragged_stats = g.tensor_like(batch_offsets_stats)
ragged_stats.set_uid(UIDs.RAGGED_STATS_UID.value)
Stats.set_ragged_offset(ragged_stats)
O.set_uid(UIDs.O_UID.value).set_output(True).set_dim(
[graph_b, h_qo, graph_s_qo, d_vo]
).set_stride(
[graph_s_qo * d_vo * h_qo, d_vo, d_vo * h_qo, 1]
).set_data_type(cudnn.data_type.BFLOAT16)
if return_lse:
Stats.set_uid(UIDs.STATS_UID.value).set_output(
return_lse
).set_data_type(cudnn.data_type.FLOAT).set_dim(
[graph_b, h_qo, graph_s_qo, 1]
).set_stride([graph_s_qo * h_qo, 1, h_qo, 1])
tensors_to_return = [cudnn_q, cudnn_k_cache, cudnn_v_cache, O]
if return_lse:
tensors_to_return.append(Stats)
if actual_seq_lens_q is not None:
tensors_to_return.append(cudnn_actual_seq_lens_q)
if actual_seq_lens_kv is not None:
tensors_to_return.append(cudnn_actual_seq_lens_kv)
return g, tensors_to_return
def _batch_prefill_with_kv_cache(
q: torch.Tensor,
k_cache: torch.Tensor,
v_cache: torch.Tensor,
scale: float,
workspace_buffer: torch.Tensor,
*,
max_token_per_sequence: int,
max_sequence_kv: int,
actual_seq_lens_q: torch.Tensor,
actual_seq_lens_kv: torch.Tensor,
block_tables: Optional[torch.Tensor] = None,
causal: bool,
return_lse: bool,
batch_offsets_q: Optional[torch.Tensor] = None,
batch_offsets_o: Optional[torch.Tensor] = None,
batch_offsets_k: Optional[torch.Tensor] = None,
batch_offsets_v: Optional[torch.Tensor] = None,
batch_offsets_stats: Optional[torch.Tensor] = None,
out: Optional[torch.Tensor] = None,
lse: Optional[torch.Tensor] = None,
) -> tuple[torch.Tensor, torch.Tensor]:
graph, tensors = _build_prefill_graph(
q=q,
k_cache=k_cache,
v_cache=v_cache,
scale=scale,
max_token_seq_q=max_token_per_sequence,
max_sequence_kv=max_sequence_kv,
actual_seq_lens_q=actual_seq_lens_q,
actual_seq_lens_kv=actual_seq_lens_kv,
block_tables=block_tables,
bottom_right_causal_mask=causal,
return_lse=return_lse,
batch_offsets_q=batch_offsets_q,
batch_offsets_o=batch_offsets_o,
batch_offsets_k=batch_offsets_k,
batch_offsets_v=batch_offsets_v,
batch_offsets_stats=batch_offsets_stats,
out=out,
lse=lse,
)
var_map = {
UIDs.Q_UID.value: q,
UIDs.K_UID.value: k_cache,
UIDs.V_UID.value: v_cache,
UIDs.O_UID.value: out,
}
if actual_seq_lens_q is not None:
var_map[UIDs.ACTUAL_SEQ_LENS_Q_UID.value] = actual_seq_lens_q
if actual_seq_lens_kv is not None:
var_map[UIDs.ACTUAL_SEQ_LENS_KV_UID.value] = actual_seq_lens_kv
if batch_offsets_q is not None:
var_map[UIDs.RAGGED_Q_UID.value] = batch_offsets_q
if batch_offsets_o is not None:
var_map[UIDs.RAGGED_O_UID.value] = batch_offsets_o
if batch_offsets_k is not None:
var_map[UIDs.RAGGED_K_UID.value] = batch_offsets_k
if batch_offsets_v is not None:
var_map[UIDs.RAGGED_V_UID.value] = batch_offsets_v
if block_tables is not None:
var_map[UIDs.BLOCK_TABLES_K_UID.value] = block_tables
var_map[UIDs.BLOCK_TABLES_V_UID.value] = block_tables
if return_lse:
var_map[UIDs.STATS_UID.value] = lse
if batch_offsets_stats is not None:
var_map[UIDs.RAGGED_STATS_UID.value] = batch_offsets_stats
handle = _create_cudnn_handle(torch.cuda.current_stream(q.device))
graph.execute(var_map, workspace=workspace_buffer, handle=handle)
if return_lse:
return out, lse
else:
return out, None
def cudnn_batch_prefill_with_kv_cache(
q: torch.Tensor,
k_cache: torch.Tensor,
v_cache: torch.Tensor,
scale: float,
workspace_buffer: torch.Tensor,
*,
max_token_per_sequence: int,
max_sequence_kv: int,
actual_seq_lens_q: torch.Tensor,
actual_seq_lens_kv: torch.Tensor,
block_tables: Optional[torch.Tensor] = None,
causal: bool,
return_lse: bool,
batch_offsets_q: Optional[torch.Tensor] = None,
batch_offsets_o: Optional[torch.Tensor] = None,
batch_offsets_k: Optional[torch.Tensor] = None,
batch_offsets_v: Optional[torch.Tensor] = None,
batch_offsets_stats: Optional[torch.Tensor] = None,
out: Optional[torch.Tensor] = None,
lse: Optional[torch.Tensor] = None,
is_cuda_graph_compatible: bool = False,
backend: Optional[str] = None,
) -> tuple[torch.Tensor, Optional[torch.Tensor]]:
"""Performs batched prefill attention with paged KV cache using cuDNN.
Args:
q: Query tensor of shape (Total number of tokens, num_heads_qo, head_dim)
k_cache: Key cache tensor of shape (total_num_pages, num_heads_kv, page_size, head_dim) if paged kv cache is enabled else (Total sequence length of kv, num_heads_kv, d_qk)
v_cache: Value cache tensor of shape (total_num_pages, num_heads_kv, page_size, head_dim) if paged kv cache is enabled else (Total sequence length of kv, num_heads_kv, d_vo)
scale: Scaling factor for attention scores, typically 1/sqrt(head_dim)
workspace_buffer: Workspace buffer for cuDNN operations. Scales with batch size. 128 MB should be sufficient for most cases
max_token_per_sequence: Maximum number of tokens per query sequence (s_qo_max)
max_sequence_kv: Maximum number of tokens per key/value sequence (s_kv_max)
actual_seq_lens_q: Actual number of tokens per query sequence shape (batch_size,) on cpu or device (cpu if cuda_graph is False)
actual_seq_lens_kv: Actual sequence lengths for key/values per batch, shape (batch_size,) on CPU or device (cpu if cuda_graph is False)
block_tables: Page table mapping for KV cache, shape (batch_size, num_pages_per_seq) on GPU
causal: Whether to apply causal masking
return_lse: Whether to return log-sum-exp values (must be True)
out: Optional pre-allocated output tensor
lse: Optional pre-allocated tensor for log-sum-exp values if return_lse is True else returns None
is_cuda_graph_compatible: Whether the prefill operation is compatible with CUDA graph
batch_offsets_q: Optional batch offsets for query tensor of shape (batch_size,) on GPU
batch_offsets_o: Optional batch offsets for output tensor of shape (batch_size,) on GPU
batch_offsets_k: Optional batch offsets for key tensor of shape (batch_size,) on GPU
batch_offsets_v: Optional batch offsets for value tensor of shape (batch_size,) on GPU
Returns:
Output tensor of shape (batch_size * seq_len_q, num_heads_qo, head_dim)
If return_lse is True, also returns log-sum-exp tensor of shape (batch_size, seq_len_q, num_heads_qo)
Note:
Query and KV heads can have different sizes (num_heads_qo >= num_heads_kv)
When using cuda graph, actual_seq_lens_q and actual_seq_lens_kv must be on the same device as q
Head dimension of query and key must be 128 or 192
Head dimension of value and output must be 128
"""
num_tokens = q.shape[0]
num_sequences = actual_seq_lens_q.shape[0]
if q.dim() == 3:
h_qo, d_qk = q.shape[1], q.shape[2]
elif q.dim() == 4:
h_qo, d_qk = q.shape[1], q.shape[3]
if v_cache.dim() == 3:
d_vo = v_cache.shape[2]
elif v_cache.dim() == 4:
d_vo = v_cache.shape[3]
if return_lse:
if lse is None:
lse = torch.empty(
num_sequences,
max_token_per_sequence,
h_qo,
device=q.device,
dtype=torch.float32,
)
if lse is not None and lse.shape != (num_sequences, max_token_per_sequence, h_qo):
raise ValueError(
"lse must have shape (num_sequences, max_token_per_sequence, h_qo)"
)
if out is None:
out_shape = (num_tokens, h_qo, d_vo)
out = torch.empty(out_shape, device=q.device, dtype=q.dtype)
if CUDNN_AVAILABLE and backend != "cubin":
return _batch_prefill_with_kv_cache(
q=q,
k_cache=k_cache,
v_cache=v_cache,
scale=scale,
workspace_buffer=workspace_buffer,
max_token_per_sequence=max_token_per_sequence,
max_sequence_kv=max_sequence_kv,
actual_seq_lens_q=actual_seq_lens_q,
actual_seq_lens_kv=actual_seq_lens_kv,
block_tables=block_tables,
causal=causal,
return_lse=return_lse,
batch_offsets_q=batch_offsets_q,
batch_offsets_o=batch_offsets_o,
batch_offsets_k=batch_offsets_k,
batch_offsets_v=batch_offsets_v,
batch_offsets_stats=batch_offsets_stats,
out=out,
lse=lse,
)
else:
assert return_lse, "Currently only supports return_lse = True"
assert (d_qk == 192 and block_tables is None) or (
d_qk == 128 and block_tables is not None
), (
"Currently only supports if d_qk = 192 and block_tables is None or d_qk = 128 and block_tables is not None"
)
if max_sequence_kv is None:
max_sequence_kv = max_token_per_sequence
actual_seq_lens_q_gpu = actual_seq_lens_q.to(q.device, non_blocking=True)
actual_seq_lens_kv_gpu = actual_seq_lens_kv.to(q.device, non_blocking=True)
run_func = get_cudnn_fmha_gen_module().prefill
run_func(
num_sequences,
max_token_per_sequence, # max_s_qo
max_sequence_kv, # max_s_kv
q,
k_cache,
v_cache,
scale,
workspace_buffer,
actual_seq_lens_q, # actual_seq_lens_q
actual_seq_lens_kv, # actual_seq_lens_kv
actual_seq_lens_q_gpu,
actual_seq_lens_kv_gpu,
block_tables,
causal,
return_lse,
out,
lse,
None,
None,
None,
None,
is_cuda_graph_compatible,
)
return out, lse