695e5c9ebc
### What this PR does / why we need it? With CANN 8.3 and corresponding PTA 2.7.1, `npu_top_k_top_p` supports passing only k (1<=k<=1024) and p separately. ### Does this PR introduce _any_ user-facing change? No. ### How was this patch tested? E2E performance test with only `top_k` and `p` seperately. This pr gains 0.2ms improvements in TPOT with `batch_size=16`. Signed-off-by: linfeng-yuan <1102311262@qq.com>
75 lines
2.8 KiB
Python
75 lines
2.8 KiB
Python
import torch
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import torch_npu
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from vllm.v1.sample.ops.topk_topp_sampler import TopKTopPSampler, random_sample
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from vllm.v1.sample.sampler import Sampler
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from vllm_ascend.utils import is_310p
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DEFAULT_LOGPROBS_MODE = "raw_logprobs"
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class AscendSampler(Sampler):
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def __init__(self, logprobs_mode=DEFAULT_LOGPROBS_MODE):
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# TODO: support logprobs_mode in vllm-ascend
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super().__init__(logprobs_mode=logprobs_mode)
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self.topk_topp_sampler = AscendTopKTopPSampler()
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class AscendTopKTopPSampler(TopKTopPSampler):
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def _apply_top_k_top_p(
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self,
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logits: torch.Tensor,
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k: torch.Tensor,
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p: torch.Tensor,
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) -> torch.Tensor:
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if p is None and k is None:
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return logits
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# npu_top_k_top_p uses the operator aclnnApplyTopKTopP, but aclnnApplyTopKTopP currently does not support 310P
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if not is_310p():
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# npu_top_k_top_p requires parameter k ranged from 1 to 1024
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if k is None or 1 <= int(k.max()) <= 1024:
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# npu_top_k_top_p's parameter order is (logits, p, k), not (logits, k, p)
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return torch_npu.npu_top_k_top_p(logits, p, k)
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probs = logits.softmax(dim=-1)
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probs_sort, _ = probs.sort(dim=-1, descending=False)
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if k is not None:
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top_k_count = probs_sort.size(1) - k.to(
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torch.long) # shape: (batch, )
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top_k_count = top_k_count.unsqueeze(dim=1)
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top_k_cutoff = probs_sort.gather(-1, top_k_count)
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# Make sure the no top-k rows are no-op.
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no_top_k_mask = (k == logits.shape[1]).unsqueeze(dim=1)
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top_k_cutoff.masked_fill_(no_top_k_mask, -float("inf"))
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elements_to_discard = probs < top_k_cutoff
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logits.masked_fill_(elements_to_discard, -float("inf"))
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if p is not None:
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cumprob = torch.cumsum(probs_sort, dim=-1)
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top_p_mask = cumprob <= 1 - p.unsqueeze(dim=1)
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top_p_mask[:, -1] = False # at least one
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top_p_count = top_p_mask.sum(dim=-1).unsqueeze(1)
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top_p_cutoff = probs_sort.gather(-1, top_p_count)
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elements_to_discard = probs < top_p_cutoff
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logits.masked_fill_(elements_to_discard, -float("inf"))
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return logits
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def forward_native(self, logits, generators, k, p):
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"""Override pytorch native implementation to torch_npu"""
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logits = self._apply_top_k_top_p(logits, k, p)
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logits_to_return = None
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if self.logprobs_mode == "processed_logits":
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logits_to_return = logits
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elif self.logprobs_mode == "processed_logprobs":
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logits_to_return = logits.log_softmax(dim=-1, dtype=torch.float32)
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probs = logits.softmax(dim=-1, dtype=torch.float32)
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return random_sample(probs, generators), logits_to_return
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