[3/N][CP] Implement zigzag CP strategy (#28421)

This commit is contained in:
Baizhou Zhang
2026-06-18 15:10:30 -07:00
committed by GitHub
parent 9fc9d37f6d
commit e3026ef016
13 changed files with 1091 additions and 56 deletions
@@ -13,6 +13,8 @@ from sglang.srt.layers.attention.triton_ops.metadata import (
prepare_swa_spec_page_table_triton,
)
from sglang.srt.layers.attention.utils import assert_buffer_fits
from sglang.srt.layers.cp.base import CPAttentionBackendKind, get_cp_strategy
from sglang.srt.layers.cp.utils import is_cp_v2_active
from sglang.srt.layers.radix_attention import AttentionType
from sglang.srt.layers.utils.cp_utils import (
cp_allgather_and_save_kv_cache,
@@ -811,18 +813,26 @@ class FlashAttentionBackend(AttentionBackend):
elif is_cp_mode:
# Dense-MHA CP: k, v are still rank-local; backend
# all-gathers and writes to the per-rank pool.
cp_allgather_and_save_kv_cache(
forward_batch,
layer,
k,
v,
self.attn_cp_size,
swa_loc=(
self.forward_metadata.swa_out_cache_loc
if self.use_sliding_window_kv_pool
else None
),
swa_loc = (
self.forward_metadata.swa_out_cache_loc
if self.use_sliding_window_kv_pool
else None
)
if is_cp_v2_active(forward_batch):
cp_strategy = get_cp_strategy()
assert cp_strategy is not None
cp_strategy.materialize_full_kv(
forward_batch, layer, k, v, swa_loc=swa_loc
)
else:
cp_allgather_and_save_kv_cache(
forward_batch,
layer,
k,
v,
self.attn_cp_size,
swa_loc=swa_loc,
)
else:
self.token_to_kv_pool.set_kv_buffer(
layer,
@@ -967,12 +977,24 @@ class FlashAttentionBackend(AttentionBackend):
**kwargs,
)
result = cp_attn_forward_extend(
forward_batch,
q.contiguous().view(-1, layer.tp_q_head_num, layer.head_dim),
self.device,
_fa_cp_attn,
)
q_cp = q.contiguous().view(-1, layer.tp_q_head_num, layer.head_dim)
if is_cp_v2_active(forward_batch):
cp_strategy = get_cp_strategy()
assert cp_strategy is not None
result = cp_strategy.run_attention(
q_cp,
forward_batch,
self.device,
_fa_cp_attn,
attention_backend=CPAttentionBackendKind.FLASH_ATTENTION,
)
else:
result = cp_attn_forward_extend(
forward_batch,
q_cp,
self.device,
_fa_cp_attn,
)
elif self.fa_skip_kv_cache:
# Embedding mode: skip KV cache read and use raw K/V tensors
# directly via flash_attn_varlen_func. The KV cache write is
+4 -8
View File
@@ -185,6 +185,7 @@ class ContextParallelStrategy(ABC):
layer: Any,
k: Any,
v: Any,
swa_loc: Optional[Any] = None,
) -> None:
"""Write full-layout K/V to the backend cache if needed."""
@@ -235,7 +236,7 @@ def init_cp_strategy(server_args: ServerArgs) -> None:
)
def _get_cp_strategy() -> Optional[ContextParallelStrategy]:
def get_cp_strategy() -> Optional[ContextParallelStrategy]:
"""Return the configured strategy, initializing lazily on first call.
Subprocesses re-import this module with ``_STRATEGY = None`` and never
@@ -257,20 +258,15 @@ def _get_cp_strategy() -> Optional[ContextParallelStrategy]:
return _STRATEGY
def get_cp_strategy() -> Optional[ContextParallelStrategy]:
"""Return the configured CP strategy for runtime dispatch."""
return _get_cp_strategy()
def get_cp_strategy_kind() -> ContextParallelStrategyKind:
strategy = _get_cp_strategy()
strategy = get_cp_strategy()
if strategy is None:
return ContextParallelStrategyKind.NONE
return strategy.kind
def is_cp_enabled() -> bool:
return _get_cp_strategy() is not None
return get_cp_strategy() is not None
def is_zigzag() -> bool:
+3 -1
View File
@@ -99,7 +99,9 @@ class InterleaveCPStrategy(ContextParallelStrategy):
"Interleave attention dispatch will land in a follow-up PR"
)
def materialize_full_kv(self, forward_batch, layer: Any, k: Any, v: Any) -> None:
def materialize_full_kv(
self, forward_batch, layer: Any, k: Any, v: Any, swa_loc: Optional[Any] = None
) -> None:
raise NotImplementedError(
"Interleave KV materialization will land in a follow-up PR"
)
+101 -1
View File
@@ -12,13 +12,16 @@
# limitations under the License.
# ==============================================================================
"""Public import facade for context parallel strategy helpers."""
"""Public import facade and runtime helpers for context parallel strategies."""
from typing import Any, Optional, Tuple
from sglang.srt.layers.cp.base import (
BaseContextParallelMetadata,
ContextParallelStrategy,
ContextParallelStrategyKind,
CPAttentionBackendKind,
get_cp_strategy,
)
from sglang.srt.layers.cp.interleave import (
InterleaveContextParallelMetadata,
@@ -30,6 +33,96 @@ from sglang.srt.layers.cp.zigzag import (
ZigzagCPStrategy,
)
CP_V2_DEFAULT_MODEL_CLASSES = frozenset(
{
"Qwen3MoeForCausalLM",
}
)
def enable_cp_v2() -> bool:
"""Return whether the CP-v2 path is enabled for this process."""
from sglang.srt.environ import envs
return bool(envs.SGLANG_ENABLE_CP_V2.get())
def is_cp_v2_active(forward_batch) -> bool:
"""Return whether the current forward batch is running through CP-v2."""
if not enable_cp_v2():
return False
forward_mode = getattr(forward_batch, "forward_mode", None)
if forward_mode is None or not forward_mode.is_context_parallel_extend():
return False
strategy = get_cp_strategy()
if strategy is None:
return False
input_ids = getattr(forward_batch, "input_ids", None)
if input_ids is None:
return False
return strategy.can_apply(len(input_ids), forward_batch)
def prepare_cp_forward(forward_batch) -> None:
"""Build CP-v2 metadata for an active context-parallel prefill batch."""
assert is_cp_v2_active(forward_batch)
strategy = get_cp_strategy()
assert strategy is not None
num_tokens = len(forward_batch.input_ids)
seq_lens_cpu = _to_int_list(getattr(forward_batch, "seq_lens_cpu", None))
extend_lens_cpu = _to_int_list(getattr(forward_batch, "extend_seq_lens_cpu", None))
forward_batch.attn_cp_metadata = strategy.build_metadata(
num_tokens=num_tokens,
seqs_len=seq_lens_cpu,
extend_seqs_len=extend_lens_cpu,
)
def cp_split_before_forward(
complete_hidden_states: Any,
complete_position_ids: Any,
forward_batch,
) -> Tuple[Optional[Any], Optional[Any]]:
"""Shard embeddings and positions for CP-v2 model-runner forwarding."""
assert is_cp_v2_active(forward_batch)
strategy = get_cp_strategy()
assert strategy is not None
assert complete_hidden_states is not None
assert getattr(forward_batch, "attn_cp_metadata", None) is not None
return (
strategy.shard_hidden_states(complete_hidden_states, forward_batch),
strategy.shard_position_ids(complete_position_ids, forward_batch),
)
def cp_gather_after_forward(x: Any, forward_batch, stream: Optional[Any] = None):
"""Gather CP-v2 hidden states at the model boundary when this batch is active."""
assert is_cp_v2_active(forward_batch)
strategy = get_cp_strategy()
assert strategy is not None
if isinstance(x, tuple):
hidden_states, *rest = x
hidden_states = strategy.gather_hidden_states(
hidden_states, forward_batch, stream
)
return (hidden_states, *rest)
return strategy.gather_hidden_states(x, forward_batch, stream)
def _to_int_list(values) -> Optional[list[int]]:
if values is None:
return None
if hasattr(values, "tolist"):
values = values.tolist()
return [int(x) for x in values]
__all__ = [
"BaseContextParallelMetadata",
"CPAttentionBackendKind",
@@ -40,4 +133,11 @@ __all__ = [
"InterleaveContextParallelMetadata",
"ZigzagCPStrategy",
"ZigzagContextParallelMetadata",
"CP_V2_DEFAULT_MODEL_CLASSES",
"enable_cp_v2",
"get_cp_strategy",
"is_cp_v2_active",
"cp_gather_after_forward",
"cp_split_before_forward",
"prepare_cp_forward",
]
+264 -15
View File
@@ -30,15 +30,29 @@ After all-gather, the blocks are reranged back to their original order:
from __future__ import annotations
from contextlib import nullcontext
from dataclasses import dataclass
from itertools import accumulate
from typing import Any, List, Optional
import torch
import torch.nn.functional as F
from sglang.srt.distributed.device_communicators.pynccl_allocator import (
use_symmetric_memory,
)
from sglang.srt.layers.cp.base import (
BaseContextParallelMetadata,
ContextParallelStrategy,
ContextParallelStrategyKind,
CPAttentionBackendKind,
)
from sglang.srt.layers.dp_attention import (
get_attention_cp_group,
is_allocation_symmetric,
)
from sglang.srt.mem_cache.memory_pool import KVWriteLoc
from sglang.srt.model_executor.forward_context import get_token_to_kv_pool
@dataclass
@@ -85,7 +99,13 @@ class ZigzagCPStrategy(ContextParallelStrategy):
if self.cp_size <= 1 or num_tokens < self.cp_size * 2:
return False
forward_mode = getattr(forward_batch, "forward_mode", None)
return forward_mode is None or forward_mode.is_context_parallel_extend()
if forward_mode is not None and not forward_mode.is_context_parallel_extend():
return False
extend_lens = getattr(forward_batch, "extend_seq_lens_cpu", None)
if extend_lens is None:
return True
return all(int(length) >= self.cp_size * 2 for length in extend_lens)
def build_metadata(
self,
@@ -93,32 +113,193 @@ class ZigzagCPStrategy(ContextParallelStrategy):
seqs_len: Optional[List[int]],
extend_seqs_len: Optional[List[int]] = None,
) -> ZigzagContextParallelMetadata:
if extend_seqs_len is None:
extend_seqs_len = seqs_len or [num_tokens]
extend_seqs_len = [int(x) for x in extend_seqs_len]
pad_len = int(num_tokens) - sum(extend_seqs_len)
if pad_len > 0:
extend_seqs_len[-1] += pad_len
if seqs_len is not None and len(seqs_len) == len(extend_seqs_len):
seqs_len = list(seqs_len)
seqs_len[-1] += pad_len
bs = len(extend_seqs_len)
cp_segment_num = self.cp_size * 2
if seqs_len is not None and len(seqs_len) == bs:
prefix_offsets = [
max(int(seqs_len[i]) - extend_seqs_len[i], 0) for i in range(bs)
]
else:
prefix_offsets = [0] * bs
# TODO: move these per-request layout/index computations to a Triton
# kernel if Python-side metadata construction becomes a bottleneck.
per_seq_block_sizes: List[List[int]] = []
split_list: List[int] = []
for length in extend_seqs_len:
base = length // cp_segment_num
rem = length % cp_segment_num
block_sizes = [
base + 1 if block_id < rem else base
for block_id in range(cp_segment_num)
]
per_seq_block_sizes.append(block_sizes)
split_list.extend(block_sizes)
per_rank_actual_token = []
for rank in range(self.cp_size):
per_rank_actual_token.append(
sum(
block_sizes[rank] + block_sizes[cp_segment_num - 1 - rank]
for block_sizes in per_seq_block_sizes
)
)
max_rank_len = [max(per_rank_actual_token)] * self.cp_size
cp_rank = self.cp_rank
zigzag_index = list(
range(cp_rank, cp_rank + bs * cp_segment_num, cp_segment_num)
) + list(
range(
cp_segment_num - cp_rank - 1,
bs * cp_segment_num,
cp_segment_num,
)
)
cp_reverse_index: List[int] = []
for batch_id in range(bs):
cp_reverse_index.extend(
list(range(batch_id, cp_segment_num * bs, 2 * bs))
+ list(
range(
(cp_segment_num - 1) * bs + batch_id,
0,
-2 * bs,
)
)
)
reverse_split_len: List[int] = []
for rank in range(self.cp_size):
for batch_id in range(bs):
reverse_split_len.append(per_seq_block_sizes[batch_id][rank])
for batch_id in range(bs):
reverse_split_len.append(
per_seq_block_sizes[batch_id][cp_segment_num - 1 - rank]
)
kv_len_prev_list: List[int] = []
kv_len_next_list: List[int] = []
actual_seq_q_prev_list: List[int] = []
actual_seq_q_next_list: List[int] = []
for batch_id, block_sizes in enumerate(per_seq_block_sizes):
kv_len_prev_list.append(
prefix_offsets[batch_id] + sum(block_sizes[: cp_rank + 1])
)
kv_len_next_list.append(
prefix_offsets[batch_id] + sum(block_sizes[: cp_segment_num - cp_rank])
)
actual_seq_q_prev_list.append(block_sizes[cp_rank])
actual_seq_q_next_list.append(block_sizes[cp_segment_num - cp_rank - 1])
from sglang.srt.server_args import get_global_server_args
try:
device = torch.device(get_global_server_args().device)
except Exception:
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
cu_prev = [0] + list(accumulate(actual_seq_q_prev_list))
cu_next = [0] + list(accumulate(actual_seq_q_next_list))
total_seq_lens = sum(extend_seqs_len)
assert len(split_list) == bs * cp_segment_num
assert sum(split_list) == total_seq_lens
assert len(zigzag_index) == 2 * bs
assert len(cp_reverse_index) == bs * cp_segment_num
assert sorted(cp_reverse_index) == list(range(bs * cp_segment_num))
assert sum(per_rank_actual_token) == total_seq_lens
return ZigzagContextParallelMetadata(
total_seq_lens=sum(extend_seqs_len or seqs_len or [num_tokens]),
bs=len(extend_seqs_len or seqs_len or [num_tokens]),
split_list=split_list,
zigzag_index=zigzag_index,
cp_reverse_index=cp_reverse_index,
reverse_split_len=reverse_split_len,
per_rank_actual_token=per_rank_actual_token,
max_rank_len=max_rank_len,
kv_len_prev_tensor=torch.tensor(
kv_len_prev_list, device=device, dtype=torch.int32
),
kv_len_next_tensor=torch.tensor(
kv_len_next_list, device=device, dtype=torch.int32
),
actual_seq_q_prev_tensor=torch.tensor(
actual_seq_q_prev_list, device=device, dtype=torch.int32
),
actual_seq_q_next_tensor=torch.tensor(
actual_seq_q_next_list, device=device, dtype=torch.int32
),
cu_seqlens_q_prev_tensor=torch.tensor(
cu_prev, device=device, dtype=torch.int32
),
cu_seqlens_q_next_tensor=torch.tensor(
cu_next, device=device, dtype=torch.int32
),
total_q_prev_tokens=cu_prev[-1],
total_q_next_tokens=cu_next[-1],
max_seqlen_q_prev=(
max(actual_seq_q_prev_list) if actual_seq_q_prev_list else 0
),
max_seqlen_q_next=(
max(actual_seq_q_next_list) if actual_seq_q_next_list else 0
),
kv_len_prev_list=kv_len_prev_list,
kv_len_next_list=kv_len_next_list,
actual_seq_q_prev_list=actual_seq_q_prev_list,
actual_seq_q_next_list=actual_seq_q_next_list,
total_seq_lens=total_seq_lens,
bs=bs,
)
def shard_hidden_states(self, x: Any, forward_batch) -> Any:
raise NotImplementedError(
"Zigzag hidden-state sharding will land in a follow-up PR"
chunks = torch.split(x, forward_batch.attn_cp_metadata.split_list, dim=0)
return torch.cat(
[chunks[i] for i in forward_batch.attn_cp_metadata.zigzag_index], dim=0
)
def shard_position_ids(self, positions: Any, forward_batch) -> Any:
raise NotImplementedError(
"Zigzag position-id sharding will land in a follow-up PR"
chunks = torch.split(
positions, forward_batch.attn_cp_metadata.split_list, dim=-1
)
return torch.cat(
[chunks[i] for i in forward_batch.attn_cp_metadata.zigzag_index], dim=-1
)
def gather_hidden_states(
self, x: Any, forward_batch, stream: Optional[Any] = None
) -> Any:
raise NotImplementedError(
"Zigzag hidden-state gather will land in a follow-up PR"
gathered = self._all_gather_reorganized(x, forward_batch, stream)
chunks = torch.split(
gathered, forward_batch.attn_cp_metadata.reverse_split_len, dim=0
)
return torch.cat(
[chunks[i] for i in forward_batch.attn_cp_metadata.cp_reverse_index], dim=0
)
def gather_kv_cache(
self, x: Any, forward_batch, stream: Optional[Any] = None
) -> Any:
raise NotImplementedError("Zigzag KV gather will land in a follow-up PR")
gathered = self._all_gather_reorganized(x, forward_batch, stream)
chunks = torch.split(
gathered, forward_batch.attn_cp_metadata.reverse_split_len, dim=0
)
return torch.cat(
[chunks[i] for i in forward_batch.attn_cp_metadata.cp_reverse_index], dim=0
)
def get_supported_attention_backend(self):
return [CPAttentionBackendKind.FLASH_ATTENTION]
def run_attention(
self,
@@ -128,11 +309,79 @@ class ZigzagCPStrategy(ContextParallelStrategy):
attn_fn,
attention_backend: CPAttentionBackendKind = CPAttentionBackendKind.FLASH_ATTENTION,
) -> Any:
raise NotImplementedError(
"Zigzag attention dispatch will land in a follow-up PR"
assert (
attention_backend in self.get_supported_attention_backend()
), f"{self.name} CP does not support {attention_backend=}"
meta = forward_batch.attn_cp_metadata
q_prev = q[: meta.total_q_prev_tokens]
q_next = q[meta.total_q_prev_tokens :]
result_prev = attn_fn(
q_prev,
meta.cu_seqlens_q_prev_tensor,
meta.kv_len_prev_tensor,
meta.max_seqlen_q_prev,
)
result_next = attn_fn(
q_next,
meta.cu_seqlens_q_next_tensor,
meta.kv_len_next_tensor,
meta.max_seqlen_q_next,
)
return torch.cat([result_prev, result_next], dim=0)
def materialize_full_kv(
self, forward_batch, layer: Any, k: Any, v: Any, swa_loc: Optional[Any] = None
) -> None:
cache_loc = (
forward_batch.out_cache_loc
if not layer.is_cross_attention
else forward_batch.encoder_out_cache_loc
)
key_cache_full = self.gather_kv_cache(
k.contiguous(), forward_batch, torch.cuda.current_stream()
)
value_cache_full = self.gather_kv_cache(
v.contiguous(), forward_batch, torch.cuda.current_stream()
)
get_token_to_kv_pool().set_kv_buffer(
layer,
KVWriteLoc(cache_loc, swa_loc),
key_cache_full,
value_cache_full,
layer.k_scale,
layer.v_scale,
)
def materialize_full_kv(self, forward_batch, layer: Any, k: Any, v: Any) -> None:
raise NotImplementedError(
"Zigzag KV materialization will land in a follow-up PR"
def _all_gather_reorganized(self, x: torch.Tensor, forward_batch, stream):
meta = forward_batch.attn_cp_metadata
max_len = meta.max_rank_len[0]
pad_size = max_len - x.shape[0]
if pad_size > 0:
padding = [0, 0] * (x.ndim - 1) + [0, pad_size]
x = F.pad(x, padding, mode="constant", value=0)
group = get_attention_cp_group()
ctx = (
use_symmetric_memory(group, disabled=not is_allocation_symmetric())
if x.is_cuda
else nullcontext()
)
with ctx:
gathered = torch.empty(
max_len * self.cp_size,
*x.shape[1:],
device=x.device,
dtype=x.dtype,
)
group.cp_all_gather_into_tensor_async(gathered, x, stream)
chunks = torch.split(gathered, meta.max_rank_len, dim=0)
return torch.cat(
[
chunks[rank][:per_rank_len]
for rank, per_rank_len in enumerate(meta.per_rank_actual_token)
],
dim=0,
)
@@ -123,6 +123,13 @@ from sglang.srt.layers.attention.attention_registry import (
)
from sglang.srt.layers.attention.dsa.utils import is_dsa_enable_prefill_cp
from sglang.srt.layers.attention.tbo_backend import TboAttnBackend
from sglang.srt.layers.cp.utils import (
cp_gather_after_forward,
cp_split_before_forward,
get_cp_strategy,
is_cp_v2_active,
prepare_cp_forward,
)
from sglang.srt.layers.dp_attention import (
DpPaddingMode,
get_attention_tp_group,
@@ -3411,6 +3418,8 @@ class ModelRunner(ModelRunnerKVCacheMixin):
self.prefill_cuda_graph_runner is not None
and self.prefill_cuda_graph_runner.can_run(forward_batch)
)
if get_cp_strategy() is not None:
can_run_graph = False
if can_run_graph:
# TODO: device_timer.wrap is too broad here — it also includes
# replay_prepare time. Move timing into the prefill cuda graph
@@ -3434,6 +3443,21 @@ class ModelRunner(ModelRunnerKVCacheMixin):
# e.g. Moss-VL's prefill cross-attention custom mask.
self.model.prepare_forward_batch(forward_batch)
self.attn_backend.init_forward_metadata(forward_batch)
cp_v2_active = is_cp_v2_active(forward_batch)
forward_positions = forward_batch.positions
if cp_v2_active:
prepare_cp_forward(forward_batch)
complete_hidden_states = kwargs.get("input_embeds")
if complete_hidden_states is None:
embed_layer = self.model.get_input_embeddings()
complete_hidden_states = embed_layer(forward_batch.input_ids)
sharded_hidden_states, sharded_positions = cp_split_before_forward(
complete_hidden_states,
forward_batch.positions,
forward_batch,
)
kwargs["input_embeds"] = sharded_hidden_states
forward_positions = sharded_positions
ctx = (
self.device_timer.wrap(metadata={"category": "extend"})
@@ -3441,7 +3465,11 @@ class ModelRunner(ModelRunnerKVCacheMixin):
else contextlib.nullcontext()
)
with ctx:
if _is_hip and self.prefill_cuda_graph_runner is not None:
if (
_is_hip
and self.prefill_cuda_graph_runner is not None
and not cp_v2_active
):
# AMD/HIP: when PCG is enabled but the batch exceeds max captured
# size, run eagerly under enable_tc_piecewise_cuda_graph() and
# set_tc_piecewise_forward_context() so that (a) Dynamo guards on
@@ -3461,14 +3489,47 @@ class ModelRunner(ModelRunnerKVCacheMixin):
):
ret = self.model.forward(
forward_batch.input_ids,
forward_batch.positions,
forward_positions,
forward_batch,
**kwargs,
)
elif cp_v2_active:
hidden_states = self.model.model(
forward_batch.input_ids,
forward_positions,
forward_batch,
input_embeds=kwargs.get("input_embeds"),
pp_proxy_tensors=kwargs.get("pp_proxy_tensors"),
)
aux_hidden_states = None
capture_aux_hidden_states = getattr(
self.model, "capture_aux_hidden_states", False
)
if capture_aux_hidden_states:
hidden_states, aux_hidden_states = hidden_states
if self.model.pp_group.is_last_rank:
hidden_states = cp_gather_after_forward(
hidden_states,
forward_batch,
torch.cuda.current_stream(),
)
ret = self.model.logits_processor(
forward_batch.input_ids,
hidden_states,
self.model.lm_head,
forward_batch,
aux_hidden_states,
)
elif capture_aux_hidden_states:
ret = hidden_states, aux_hidden_states
else:
ret = hidden_states
else:
ret = self.model.forward(
forward_batch.input_ids,
forward_batch.positions,
forward_positions,
forward_batch,
**kwargs,
)
+3
View File
@@ -42,6 +42,7 @@ from sglang.srt.layers.communicator import (
LayerScatterModes,
ScatterMode,
)
from sglang.srt.layers.cp.utils import is_cp_v2_active
from sglang.srt.layers.dp_attention import (
is_dp_attention_enabled,
)
@@ -889,6 +890,7 @@ class Qwen2MoeModel(nn.Module):
if (
is_prefill_context_parallel_enabled()
and not is_cp_v2_active(forward_batch)
and forward_batch.forward_mode.is_context_parallel_extend()
and forward_batch.attn_cp_metadata is not None
):
@@ -944,6 +946,7 @@ class Qwen2MoeModel(nn.Module):
if (
self.pp_group.is_last_rank
and not is_cp_v2_active(forward_batch)
and is_prefill_context_parallel_enabled()
and forward_batch.forward_mode.is_context_parallel_extend()
and forward_batch.attn_cp_metadata is not None
+2 -1
View File
@@ -34,6 +34,7 @@ from sglang.srt.eplb.expert_distribution import get_global_expert_distribution_r
from sglang.srt.eplb.expert_location import ModelConfigForExpertLocation
from sglang.srt.eplb.expert_location_dispatch import ExpertLocationDispatchInfo
from sglang.srt.layers.communicator import LayerCommunicator, LayerScatterModes
from sglang.srt.layers.cp.utils import is_cp_v2_active
from sglang.srt.layers.layernorm import RMSNorm
from sglang.srt.layers.linear import (
QKVParallelLinear,
@@ -988,7 +989,7 @@ class Qwen3MoeForCausalLM(nn.Module):
input_embeds: torch.Tensor = None,
pp_proxy_tensors: Optional[PPProxyTensors] = None,
) -> torch.Tensor:
if is_prefill_context_parallel_enabled():
if is_prefill_context_parallel_enabled() and not is_cp_v2_active(forward_batch):
if can_cp_split(len(input_ids), self.attn_cp_size, forward_batch):
forward_batch.attn_cp_metadata = prepare_context_parallel_metadata(
len(input_ids),
+11
View File
@@ -3436,6 +3436,17 @@ class ServerArgs:
self.prefill_cp_mode = mode
def _handle_context_parallelism(self):
if parse_connector_type(self.model_path) != ConnectorType.INSTANCE:
from sglang.srt.layers.cp.utils import CP_V2_DEFAULT_MODEL_CLASSES
model_config = self.get_model_config()
model_arch = model_config.hf_config.architectures[0]
if (
model_arch in CP_V2_DEFAULT_MODEL_CLASSES
and not envs.SGLANG_ENABLE_CP_V2.is_set()
):
envs.SGLANG_ENABLE_CP_V2.set(True)
if self.enable_prefill_cp and self.cp_strategy is None:
raise ValueError(
"--cp-strategy must be set when --enable-prefill-cp is enabled."
+386 -1
View File
@@ -2,6 +2,8 @@ import unittest
from types import SimpleNamespace
from unittest.mock import patch
import torch
from sglang.srt.layers.cp.base import (
ContextParallelStrategyKind,
get_cp_strategy,
@@ -11,10 +13,31 @@ from sglang.srt.layers.cp.base import (
is_interleave,
is_zigzag,
)
from sglang.srt.layers.cp.utils import (
cp_split_before_forward,
enable_cp_v2,
is_cp_v2_active,
)
from sglang.srt.layers.cp.zigzag import ZigzagCPStrategy
from sglang.srt.runtime_context import get_parallel
from sglang.test.ci.ci_register import register_cpu_ci
from sglang.test.test_utils import CustomTestCase
register_cpu_ci(est_time=2, suite="base-a-test-cpu")
register_cpu_ci(est_time=5, suite="base-a-test-cpu")
class _ExtendMode:
def is_context_parallel_extend(self):
return True
class _FakeCPGroup:
def __init__(self, all_rank_tensors):
self.all_rank_tensors = all_rank_tensors
def cp_all_gather_into_tensor_async(self, output, input_tensor, stream):
del input_tensor, stream
torch.cat(self.all_rank_tensors, dim=0, out=output)
class TestCPStrategyUnit(CustomTestCase):
@@ -70,5 +93,367 @@ class TestCPStrategyUnit(CustomTestCase):
self.assertIsNotNone(get_cp_strategy())
class TestCPZigzagStrategy(CustomTestCase):
def setUp(self):
init_cp_strategy(
SimpleNamespace(
enable_prefill_cp=True,
cp_strategy="zigzag",
attn_cp_size=4,
attention_backend="fa3",
)
)
def tearDown(self):
init_cp_strategy(SimpleNamespace(enable_prefill_cp=False))
def _metadata_for_rank(self, rank, *, cp_size, seq_lens, extend_seq_lens):
strategy = ZigzagCPStrategy(cp_size=cp_size)
with get_parallel().override(attn_cp_rank=rank):
return strategy.build_metadata(
num_tokens=sum(extend_seq_lens),
seqs_len=seq_lens,
extend_seqs_len=extend_seq_lens,
)
def _forward_batch(self, metadata, extend_seq_lens):
return SimpleNamespace(
input_ids=torch.arange(sum(extend_seq_lens)),
forward_mode=_ExtendMode(),
extend_seq_lens_cpu=extend_seq_lens,
attn_cp_metadata=metadata,
)
def test_enable_cp_v2_and_is_cp_v2_active(self):
active_batch = SimpleNamespace(
input_ids=torch.arange(8),
forward_mode=_ExtendMode(),
extend_seq_lens_cpu=[8],
)
inactive_batch = SimpleNamespace(
input_ids=torch.arange(7),
forward_mode=_ExtendMode(),
extend_seq_lens_cpu=[7],
)
with patch(
"sglang.srt.environ.envs.SGLANG_ENABLE_CP_V2.get", return_value=False
):
self.assertFalse(enable_cp_v2())
self.assertFalse(is_cp_v2_active(active_batch))
with patch(
"sglang.srt.environ.envs.SGLANG_ENABLE_CP_V2.get", return_value=True
):
self.assertTrue(enable_cp_v2())
self.assertTrue(is_cp_v2_active(active_batch))
self.assertFalse(is_cp_v2_active(inactive_batch))
def _expected_metadata(self, *, rank, cp_size, seq_lens, extend_seq_lens):
bs = len(extend_seq_lens)
cp_segment_num = cp_size * 2
prefix_offsets = [
max(int(seq_lens[i]) - int(extend_seq_lens[i]), 0) for i in range(bs)
]
per_seq_block_sizes = []
split_list = []
for length in extend_seq_lens:
base = length // cp_segment_num
rem = length % cp_segment_num
block_sizes = [
base + 1 if block_id < rem else base
for block_id in range(cp_segment_num)
]
per_seq_block_sizes.append(block_sizes)
split_list.extend(block_sizes)
per_rank_actual_token = [
sum(
block_sizes[rank_id] + block_sizes[cp_segment_num - 1 - rank_id]
for block_sizes in per_seq_block_sizes
)
for rank_id in range(cp_size)
]
max_rank_len = [max(per_rank_actual_token)] * cp_size
zigzag_index = list(range(rank, rank + bs * cp_segment_num, cp_segment_num))
zigzag_index += list(
range(cp_segment_num - rank - 1, bs * cp_segment_num, cp_segment_num)
)
cp_reverse_index = []
for batch_id in range(bs):
cp_reverse_index.extend(
list(range(batch_id, cp_segment_num * bs, 2 * bs))
+ list(range((cp_segment_num - 1) * bs + batch_id, 0, -2 * bs))
)
reverse_split_len = []
for rank_id in range(cp_size):
for batch_id in range(bs):
reverse_split_len.append(per_seq_block_sizes[batch_id][rank_id])
for batch_id in range(bs):
reverse_split_len.append(
per_seq_block_sizes[batch_id][cp_segment_num - 1 - rank_id]
)
kv_len_prev_list = []
kv_len_next_list = []
actual_seq_q_prev_list = []
actual_seq_q_next_list = []
for batch_id, block_sizes in enumerate(per_seq_block_sizes):
kv_len_prev_list.append(
prefix_offsets[batch_id] + sum(block_sizes[: rank + 1])
)
kv_len_next_list.append(
prefix_offsets[batch_id] + sum(block_sizes[: cp_segment_num - rank])
)
actual_seq_q_prev_list.append(block_sizes[rank])
actual_seq_q_next_list.append(block_sizes[cp_segment_num - rank - 1])
return {
"bs": bs,
"total_seq_lens": sum(extend_seq_lens),
"split_list": split_list,
"zigzag_index": zigzag_index,
"per_rank_actual_token": per_rank_actual_token,
"max_rank_len": max_rank_len,
"reverse_split_len": reverse_split_len,
"cp_reverse_index": cp_reverse_index,
"kv_len_prev_list": kv_len_prev_list,
"kv_len_next_list": kv_len_next_list,
"actual_seq_q_prev_list": actual_seq_q_prev_list,
"actual_seq_q_next_list": actual_seq_q_next_list,
}
def _assert_metadata_matches(self, metadata, expected):
self.assertEqual(metadata.bs, expected["bs"])
self.assertEqual(metadata.total_seq_lens, expected["total_seq_lens"])
self.assertEqual(metadata.split_list, expected["split_list"])
self.assertEqual(metadata.zigzag_index, expected["zigzag_index"])
self.assertEqual(
metadata.per_rank_actual_token, expected["per_rank_actual_token"]
)
self.assertEqual(metadata.max_rank_len, expected["max_rank_len"])
self.assertEqual(metadata.reverse_split_len, expected["reverse_split_len"])
self.assertEqual(metadata.cp_reverse_index, expected["cp_reverse_index"])
self.assertEqual(metadata.kv_len_prev_list, expected["kv_len_prev_list"])
self.assertEqual(metadata.kv_len_next_list, expected["kv_len_next_list"])
self.assertEqual(
metadata.actual_seq_q_prev_list, expected["actual_seq_q_prev_list"]
)
self.assertEqual(
metadata.actual_seq_q_next_list, expected["actual_seq_q_next_list"]
)
self.assertEqual(
metadata.cu_seqlens_q_prev_tensor.cpu().tolist(),
[0]
+ list(
torch.tensor(expected["actual_seq_q_prev_list"]).cumsum(dim=0).tolist()
),
)
self.assertEqual(
metadata.cu_seqlens_q_next_tensor.cpu().tolist(),
[0]
+ list(
torch.tensor(expected["actual_seq_q_next_list"]).cumsum(dim=0).tolist()
),
)
def _padded_rank_tensors(self, x, *, cp_size, seq_lens, extend_seq_lens):
per_rank = []
metas = []
for rank in range(cp_size):
metadata = self._metadata_for_rank(
rank,
cp_size=cp_size,
seq_lens=seq_lens,
extend_seq_lens=extend_seq_lens,
)
metas.append(metadata)
fb = self._forward_batch(metadata, extend_seq_lens)
local = ZigzagCPStrategy(cp_size=cp_size).shard_hidden_states(x, fb)
pad = metadata.max_rank_len[0] - local.shape[0]
if pad:
local = torch.nn.functional.pad(
local,
[0, 0] * (local.ndim - 1) + [0, pad],
)
per_rank.append(local)
return metas, per_rank
def test_zigzag_metadata_for_batched_sequences(self):
cases = [
(4, [11, 13], [9, 10]),
(2, [8], [8]),
(4, [100000, 200000, 80], [100000, 200000, 64]),
(4, [100005, 200011, 25], [100000, 200000, 16]),
]
for cp_size, seq_lens, extend_seq_lens in cases:
for rank in range(cp_size):
with self.subTest(
cp_size=cp_size,
rank=rank,
seq_lens=seq_lens,
extend_seq_lens=extend_seq_lens,
):
metadata = self._metadata_for_rank(
rank,
cp_size=cp_size,
seq_lens=seq_lens,
extend_seq_lens=extend_seq_lens,
)
expected = self._expected_metadata(
rank=rank,
cp_size=cp_size,
seq_lens=seq_lens,
extend_seq_lens=extend_seq_lens,
)
self._assert_metadata_matches(metadata, expected)
def test_zigzag_shards_hidden_states_and_position_ids(self):
cp_size = 4
seq_lens = [11, 13]
extend_seq_lens = [9, 10]
x = torch.arange(sum(extend_seq_lens) * 2).view(sum(extend_seq_lens), 2)
positions = torch.arange(sum(extend_seq_lens))
for rank in range(cp_size):
metadata = self._metadata_for_rank(
rank,
cp_size=cp_size,
seq_lens=seq_lens,
extend_seq_lens=extend_seq_lens,
)
fb = self._forward_batch(metadata, extend_seq_lens)
strategy = ZigzagCPStrategy(cp_size=cp_size)
chunks = torch.split(x, metadata.split_list, dim=0)
position_chunks = torch.split(positions, metadata.split_list, dim=-1)
expected_x = torch.cat([chunks[i] for i in metadata.zigzag_index], dim=0)
expected_positions = torch.cat(
[position_chunks[i] for i in metadata.zigzag_index], dim=-1
)
local_x = strategy.shard_hidden_states(x, fb)
local_positions = strategy.shard_position_ids(positions, fb)
with patch(
"sglang.srt.environ.envs.SGLANG_ENABLE_CP_V2.get", return_value=True
):
helper_x, helper_positions = cp_split_before_forward(
x,
positions,
fb,
)
self.assertTrue(torch.equal(local_x, expected_x))
self.assertTrue(torch.equal(local_positions, expected_positions))
self.assertTrue(torch.equal(helper_x, expected_x))
self.assertTrue(torch.equal(helper_positions, expected_positions))
def test_zigzag_gathers_hidden_states_to_original_order(self):
cp_size = 4
seq_lens = [11, 13]
extend_seq_lens = [9, 10]
x = torch.arange(sum(extend_seq_lens) * 2).view(sum(extend_seq_lens), 2)
metas, padded_rank_tensors = self._padded_rank_tensors(
x,
cp_size=cp_size,
seq_lens=seq_lens,
extend_seq_lens=extend_seq_lens,
)
for rank in range(cp_size):
local_x = padded_rank_tensors[rank][
: metas[rank].per_rank_actual_token[rank]
]
fb = self._forward_batch(metas[rank], extend_seq_lens)
with (
patch(
"sglang.srt.layers.cp.zigzag.get_attention_cp_group",
return_value=_FakeCPGroup(padded_rank_tensors),
),
patch(
"sglang.srt.distributed.device_communicators.pynccl_allocator.use_symmetric_memory",
return_value=torch.no_grad(),
),
):
gathered = ZigzagCPStrategy(cp_size=cp_size).gather_hidden_states(
local_x, fb, stream=None
)
self.assertTrue(torch.equal(gathered, x))
def test_zigzag_gathers_kv_cache_to_original_order(self):
cp_size = 4
seq_lens = [11, 13]
extend_seq_lens = [9, 10]
kv = torch.arange(sum(extend_seq_lens) * 2 * 3).view(sum(extend_seq_lens), 2, 3)
metas, padded_rank_tensors = self._padded_rank_tensors(
kv,
cp_size=cp_size,
seq_lens=seq_lens,
extend_seq_lens=extend_seq_lens,
)
for rank in range(cp_size):
local_kv = padded_rank_tensors[rank][
: metas[rank].per_rank_actual_token[rank]
]
fb = self._forward_batch(metas[rank], extend_seq_lens)
with (
patch(
"sglang.srt.layers.cp.zigzag.get_attention_cp_group",
return_value=_FakeCPGroup(padded_rank_tensors),
),
patch(
"sglang.srt.distributed.device_communicators.pynccl_allocator.use_symmetric_memory",
return_value=torch.no_grad(),
),
):
gathered = ZigzagCPStrategy(cp_size=cp_size).gather_kv_cache(
local_kv, fb, stream=None
)
self.assertTrue(torch.equal(gathered, kv))
def test_zigzag_attention_dispatch_runs_prev_then_next(self):
cp_size = 2
seq_lens = [8]
extend_seq_lens = [8]
metadata = self._metadata_for_rank(
0,
cp_size=cp_size,
seq_lens=seq_lens,
extend_seq_lens=extend_seq_lens,
)
fb = SimpleNamespace(attn_cp_metadata=metadata)
q = torch.arange(4 * 2).view(4, 2)
calls = []
def attn_fn(q_chunk, cu_seqlens_q, cache_seqlens, max_seqlen_q):
calls.append(
(
q_chunk.clone(),
cu_seqlens_q.clone(),
cache_seqlens.clone(),
max_seqlen_q,
)
)
return q_chunk + 100
out = ZigzagCPStrategy(cp_size=cp_size).run_attention(
q, fb, device=torch.device("cpu"), attn_fn=attn_fn
)
self.assertEqual(len(calls), 2)
self.assertTrue(torch.equal(calls[0][0], q[:2]))
self.assertTrue(torch.equal(calls[1][0], q[2:]))
self.assertTrue(torch.equal(out, q + 100))
if __name__ == "__main__":
unittest.main()
@@ -11,17 +11,17 @@ from sglang.test.test_utils import (
popen_launch_server,
)
register_cuda_ci(est_time=261, stage="extra-b", runner_config="4-gpu-h100")
register_cuda_ci(est_time=260, stage="extra-b", runner_config="4-gpu-h100")
QWEN3_30B_MODEL_PATH = "Qwen/Qwen3-30B-A3B-FP8"
GQA_MODEL_PATH = "Qwen/Qwen3-30B-A3B-FP8"
GSM8K_BASELINE_ACCURACY = 0.85
GSM8K_BASELINE_ACCURACY = 0.93
class TestQwen330B(CustomTestCase):
class TestGQACP2TP2EP2(CustomTestCase):
@classmethod
def setUpClass(cls):
cls.model = QWEN3_30B_MODEL_PATH
cls.model = GQA_MODEL_PATH
cls.base_url = DEFAULT_URL_FOR_TEST
cls.process = popen_launch_server(
cls.model,
@@ -46,11 +46,13 @@ class TestQwen330B(CustomTestCase):
"--model-loader-extra-config",
'{"enable_multithread_load": true, "num_threads": 64}',
],
env={"SGLANG_ENABLE_CP_V2": "0"},
)
@classmethod
def tearDownClass(cls):
kill_process_tree(cls.process.pid)
if hasattr(cls, "process") and cls.process:
kill_process_tree(cls.process.pid)
def test_gsm8k(self):
args = SimpleNamespace(
@@ -73,10 +75,10 @@ class TestQwen330B(CustomTestCase):
self.assertGreaterEqual(metrics["score"], GSM8K_BASELINE_ACCURACY)
class TestQwen330BCP(CustomTestCase):
class TestGQACPTP2CP2EP4(CustomTestCase):
@classmethod
def setUpClass(cls):
cls.model = QWEN3_30B_MODEL_PATH
cls.model = GQA_MODEL_PATH
cls.base_url = DEFAULT_URL_FOR_TEST
cls.process = popen_launch_server(
cls.model,
@@ -101,11 +103,13 @@ class TestQwen330BCP(CustomTestCase):
"--model-loader-extra-config",
'{"enable_multithread_load": true, "num_threads": 64}',
],
env={"SGLANG_ENABLE_CP_V2": "0"},
)
@classmethod
def tearDownClass(cls):
kill_process_tree(cls.process.pid)
if hasattr(cls, "process") and cls.process:
kill_process_tree(cls.process.pid)
def test_gsm8k(self):
args = SimpleNamespace(
+200
View File
@@ -0,0 +1,200 @@
import unittest
from types import SimpleNamespace
from sglang.test.ci.ci_register import register_cuda_ci
from sglang.test.run_eval import run_eval
from sglang.test.test_utils import (
DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
DEFAULT_URL_FOR_TEST,
CustomTestCase,
kill_process_tree,
popen_launch_server,
)
register_cuda_ci(est_time=500, stage="extra-b", runner_config="4-gpu-h100")
GQA_MODEL_PATH = "Qwen/Qwen3-30B-A3B-FP8"
GSM8K_BASELINE_ACCURACY = 0.93
class TestGQACP2TP2EP2(CustomTestCase):
@classmethod
def setUpClass(cls):
cls.model = GQA_MODEL_PATH
cls.base_url = DEFAULT_URL_FOR_TEST
cls.process = popen_launch_server(
cls.model,
cls.base_url,
timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
other_args=[
"--tp-size",
"4",
"--moe-dp-size",
"2",
"--ep-size",
"2",
"--attn-cp-size",
"2",
"--enable-prefill-cp",
"--cp-strategy",
"zigzag",
"--cuda-graph-max-bs",
"32",
"--max-running-requests",
"32",
"--trust-remote-code",
"--disable-piecewise-cuda-graph",
"--model-loader-extra-config",
'{"enable_multithread_load": true, "num_threads": 64}',
],
env={"SGLANG_ENABLE_CP_V2": "1"},
)
@classmethod
def tearDownClass(cls):
if hasattr(cls, "process") and cls.process:
kill_process_tree(cls.process.pid)
def test_gsm8k(self):
args = SimpleNamespace(
model=self.model,
eval_name="gsm8k",
num_shots=5,
num_examples=200,
max_tokens=16000,
num_threads=128,
repeat=1,
temperature=0.6,
top_p=0.95,
top_k=20,
base_url=self.base_url,
host="http://127.0.0.1",
port=int(self.base_url.split(":")[-1]),
)
metrics = run_eval(args)
print(f"{metrics=}")
self.assertGreaterEqual(metrics["score"], GSM8K_BASELINE_ACCURACY)
class TestGQACPTP2CP2EP4(CustomTestCase):
@classmethod
def setUpClass(cls):
cls.model = GQA_MODEL_PATH
cls.base_url = DEFAULT_URL_FOR_TEST
cls.process = popen_launch_server(
cls.model,
cls.base_url,
timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
other_args=[
"--tp-size",
"4",
"--moe-dp-size",
"1",
"--ep-size",
"4",
"--attn-cp-size",
"2",
"--enable-prefill-cp",
"--cp-strategy",
"zigzag",
"--cuda-graph-max-bs",
"32",
"--max-running-requests",
"32",
"--trust-remote-code",
"--disable-piecewise-cuda-graph",
"--model-loader-extra-config",
'{"enable_multithread_load": true, "num_threads": 64}',
],
env={"SGLANG_ENABLE_CP_V2": "1"},
)
@classmethod
def tearDownClass(cls):
if hasattr(cls, "process") and cls.process:
kill_process_tree(cls.process.pid)
def test_gsm8k(self):
args = SimpleNamespace(
model=self.model,
eval_name="gsm8k",
num_shots=5,
num_examples=200,
max_tokens=16000,
num_threads=128,
repeat=1,
temperature=0.6,
top_p=0.95,
top_k=20,
base_url=self.base_url,
host="http://127.0.0.1",
port=int(self.base_url.split(":")[-1]),
)
metrics = run_eval(args)
print(f"{metrics=}")
self.assertGreaterEqual(metrics["score"], GSM8K_BASELINE_ACCURACY)
class TestGQACPCP4EP4(CustomTestCase):
@classmethod
def setUpClass(cls):
cls.model = GQA_MODEL_PATH
cls.base_url = DEFAULT_URL_FOR_TEST
cls.process = popen_launch_server(
cls.model,
cls.base_url,
timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
other_args=[
"--tp-size",
"4",
"--ep",
"4",
"--attn-cp-size",
"4",
"--enable-prefill-cp",
"--cp-strategy",
"zigzag",
"--moe-a2a-backend",
"deepep",
"--attention-backend",
"fa3",
"--cuda-graph-max-bs",
"32",
"--max-running-requests",
"32",
"--trust-remote-code",
"--disable-piecewise-cuda-graph",
"--model-loader-extra-config",
'{"enable_multithread_load": true, "num_threads": 64}',
],
)
@classmethod
def tearDownClass(cls):
if hasattr(cls, "process") and cls.process:
kill_process_tree(cls.process.pid)
def test_gsm8k(self):
args = SimpleNamespace(
model=self.model,
eval_name="gsm8k",
num_shots=5,
num_examples=200,
max_tokens=16000,
num_threads=128,
repeat=1,
temperature=0.6,
top_p=0.95,
top_k=20,
base_url=self.base_url,
host="http://127.0.0.1",
port=int(self.base_url.split(":")[-1]),
)
metrics = run_eval(args)
print(f"{metrics=}")
self.assertGreaterEqual(metrics["score"], GSM8K_BASELINE_ACCURACY)
if __name__ == "__main__":
unittest.main()
@@ -159,6 +159,7 @@ class TestContextParallelServerArgs(CustomTestCase):
enable_dsa_prefill_context_parallel=False,
enable_prefill_cp=False,
cp_strategy=None,
model_path="instance://127.0.0.1:8000/dummy",
dsa_prefill_cp_mode="round-robin-split",
prefill_cp_mode="in-seq-split",
attn_cp_size=1,