Files
enginex-ascend-910-vllm/vllm_ascend/_310p/sample/sampler.py
Sun Ruoxi 7f8a1b1f7a init v0.23.0
Signed-off-by: Sun Ruoxi <sunruoxi@4paradigm.com>
2026-08-27 15:11:51 +08:00

129 lines
5.0 KiB
Python

#
# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
#
# 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.
# This file is a part of the vllm-ascend project.
#
import torch
import vllm.envs as envs
from vllm_ascend.ascend_config import get_ascend_config
from vllm_ascend.sample.sampler import (
DEFAULT_LOGPROBS_MODE,
AscendSampler,
AscendTopKTopPSampler,
)
from vllm_ascend.utils import global_stream, npu_stream_switch
_CPU_GENERATOR_CACHE_310P: dict[int, tuple[torch.Generator, int]] = {}
def _get_cpu_generator_310p(i: int, generator: torch.Generator) -> torch.Generator:
cache_entry = _CPU_GENERATOR_CACHE_310P.get(i)
if cache_entry is None or cache_entry[1] != id(generator):
cpu_generator = torch.Generator(device="cpu")
try:
# Keep RNG stream consistent with the original generator.
cpu_generator.set_state(generator.get_state())
except Exception:
cpu_generator.manual_seed(generator.initial_seed())
cache_entry = (cpu_generator, id(generator))
_CPU_GENERATOR_CACHE_310P[i] = cache_entry
return cache_entry[0]
def _fill_cpu_exponential_310p(
q_cpu: torch.Tensor,
generators: dict[int, torch.Generator],
has_draft_mask: torch.Tensor | None = None,
) -> None:
"""Fill a CPU tensor with exponential values for 310P stability."""
if has_draft_mask is not None:
has_draft_mask = has_draft_mask.cpu()
# Prefill all rows so unmasked requests do not keep uninitialized values.
q_cpu.exponential_()
elif len(generators) != q_cpu.shape[0]:
q_cpu.exponential_()
if not generators:
return
for i, generator in generators.items():
cpu_gen = _get_cpu_generator_310p(i, generator)
if has_draft_mask is not None:
temp_q = torch.empty_like(q_cpu[i])
temp_q.exponential_(generator=cpu_gen)
q_cpu[i] = torch.where(has_draft_mask[i], temp_q, q_cpu[i])
else:
q_cpu[i].exponential_(generator=cpu_gen)
def fill_exponential_310p(
q: torch.Tensor,
generators: dict[int, torch.Generator],
has_draft_mask: torch.Tensor | None = None,
) -> None:
"""Fill ``q`` with exponential values using CPU RNG for 310P stability."""
q_cpu = q.cpu()
_fill_cpu_exponential_310p(q_cpu, generators, has_draft_mask)
q.copy_(q_cpu.to(q.device))
# Ensure H2D of q is visible before rejection/recover consumes it.
torch.npu.current_stream().synchronize()
def _random_sample_310p(
probs: torch.Tensor,
generators: dict[int, torch.Generator],
) -> torch.Tensor:
"""310P-specific random sampling with CPU exponential generation for q."""
with npu_stream_switch(global_stream()):
q = torch.empty_like(probs).cpu()
_fill_cpu_exponential_310p(q, generators)
q = q.npu()
torch.npu.current_stream().wait_stream(global_stream())
return probs.div_(q).argmax(dim=-1).view(-1)
class AscendTopKTopPSampler310(AscendTopKTopPSampler):
def forward_native(self, logits, generators, k, p):
if envs.VLLM_BATCH_INVARIANT:
return super().forward_native(logits, generators, k, p)
if get_ascend_config().enable_reduce_sample:
cand_logits, cand_idx = self.apply_top_k_top_p(logits, k, p, self.top_k)
logits_to_return = None
if self.logprobs_mode == "processed_logits":
logits_to_return = cand_logits
elif self.logprobs_mode == "processed_logprobs":
logits_to_return = cand_logits.log_softmax(dim=-1, dtype=torch.float32)
probs = torch.softmax(cand_logits, dim=-1)
pos = _random_sample_310p(probs, generators) # [B]
next_token = cand_idx.gather(dim=1, index=pos.unsqueeze(1)).squeeze(1) # [B]
return next_token, logits_to_return
else:
logits = self.apply_top_k_top_p(logits, k, p)
logits_to_return = None
if self.logprobs_mode == "processed_logits":
logits_to_return = logits
elif self.logprobs_mode == "processed_logprobs":
logits_to_return = logits.log_softmax(dim=-1, dtype=torch.float32)
probs = logits.softmax(dim=-1, dtype=torch.float32)
return _random_sample_310p(probs, generators), logits_to_return
class AscendSampler310(AscendSampler):
def __init__(self, logprobs_mode=DEFAULT_LOGPROBS_MODE):
super().__init__(logprobs_mode=logprobs_mode)
self.topk_topp_sampler = AscendTopKTopPSampler310(logprobs_mode=logprobs_mode)