128
vllm_ascend/_310p/sample/sampler.py
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128
vllm_ascend/_310p/sample/sampler.py
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#
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# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
|
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# This file is a part of the vllm-ascend project.
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#
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import torch
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import vllm.envs as envs
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from vllm_ascend.ascend_config import get_ascend_config
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from vllm_ascend.sample.sampler import (
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DEFAULT_LOGPROBS_MODE,
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AscendSampler,
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AscendTopKTopPSampler,
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)
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from vllm_ascend.utils import global_stream, npu_stream_switch
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_CPU_GENERATOR_CACHE_310P: dict[int, tuple[torch.Generator, int]] = {}
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def _get_cpu_generator_310p(i: int, generator: torch.Generator) -> torch.Generator:
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cache_entry = _CPU_GENERATOR_CACHE_310P.get(i)
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if cache_entry is None or cache_entry[1] != id(generator):
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cpu_generator = torch.Generator(device="cpu")
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try:
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# Keep RNG stream consistent with the original generator.
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cpu_generator.set_state(generator.get_state())
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except Exception:
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cpu_generator.manual_seed(generator.initial_seed())
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cache_entry = (cpu_generator, id(generator))
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_CPU_GENERATOR_CACHE_310P[i] = cache_entry
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return cache_entry[0]
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|
||||
|
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def _fill_cpu_exponential_310p(
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q_cpu: torch.Tensor,
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generators: dict[int, torch.Generator],
|
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has_draft_mask: torch.Tensor | None = None,
|
||||
) -> None:
|
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"""Fill a CPU tensor with exponential values for 310P stability."""
|
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if has_draft_mask is not None:
|
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has_draft_mask = has_draft_mask.cpu()
|
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# Prefill all rows so unmasked requests do not keep uninitialized values.
|
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q_cpu.exponential_()
|
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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)
|
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q_cpu[i] = torch.where(has_draft_mask[i], temp_q, q_cpu[i])
|
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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)
|
||||
Reference in New Issue
Block a user