Files
sglang/python/sglang/srt/layers/logits_processor.py
2024-01-23 05:07:30 -08:00

102 lines
3.9 KiB
Python

import torch
from sglang.srt.managers.router.model_runner import ForwardMode, InputMetadata
from torch import nn
from vllm.model_executor.parallel_utils.communication_op import (
get_tensor_model_parallel_world_size,
tensor_model_parallel_all_gather,
)
class LogitsProcessor(nn.Module):
def __init__(self, config):
super().__init__()
self.config = config
self.tp_size = get_tensor_model_parallel_world_size()
def forward(self, input_ids, hidden_states, weight, input_metadata):
if not input_metadata.return_logprob:
if input_metadata.forward_mode == ForwardMode.DECODE:
last_hidden = hidden_states
else:
last_index = (
torch.cumsum(
input_metadata.seq_lens - input_metadata.prefix_lens,
dim=0,
dtype=torch.long,
)
- 1
)
last_hidden = hidden_states[last_index]
hidden_states = None
last_logits = torch.matmul(last_hidden, weight.T)
if self.tp_size > 1:
last_logits = tensor_model_parallel_all_gather(last_logits)
last_logits = last_logits[:, : self.config.vocab_size]
return last_logits, (None, None)
else:
assert input_metadata.forward_mode != ForwardMode.DECODE
last_index = (
torch.cumsum(
input_metadata.seq_lens - input_metadata.prefix_lens,
dim=0,
dtype=torch.long,
)
- 1
)
logits = torch.matmul(hidden_states, weight.T)
if self.tp_size > 1:
logits = tensor_model_parallel_all_gather(logits)
logits = logits[:, : self.config.vocab_size]
all_logprobs = torch.log(torch.softmax(logits.float(), dim=-1) + 1e-6)
logprobs = all_logprobs[
torch.arange(all_logprobs.shape[0], device="cuda"),
torch.cat([input_ids[1:], torch.tensor([0], device="cuda")]),
]
logprobs_cumsum = torch.cumsum(logprobs, dim=0, dtype=torch.float32)
start = input_metadata.extend_start_loc.clone()
end = start + input_metadata.extend_seq_lens - 2
start.clamp_(min=0, max=logprobs.shape[0] - 1)
end.clamp_(min=0, max=logprobs.shape[0] - 1)
sum_logp = logprobs_cumsum[end] - logprobs_cumsum[start] + logprobs[start]
normalized_logprobs = sum_logp / (
(input_metadata.extend_seq_lens - 1).clamp(min=1)
)
last_logits = logits[last_index]
return last_logits, (logprobs, normalized_logprobs)
if __name__ == "__main__":
all_logprobs = torch.tensor(
# s s s
[[0, 1, 2, 3], [1, 2, 3, 4], [2, 3, 4, 5], [3, 4, 5, 6], [4, 5, 6, 7]],
dtype=torch.float32,
device="cuda",
)
seq_lens = torch.tensor([2, 0, 3, 0], dtype=torch.int32, device="cuda")
input_ids = torch.tensor([1, 2, 3, 0, 1], dtype=torch.int32, device="cuda")
logprobs = torch.zeros(5, dtype=torch.float32, device="cuda")
logprobs = all_logprobs[
torch.arange(all_logprobs.shape[0], device="cuda"),
torch.cat([input_ids[1:], torch.tensor([0], device="cuda")]),
]
logprobs_cumsum = torch.cumsum(logprobs, dim=0, dtype=torch.float32)
len_cumsum = torch.cumsum(seq_lens, dim=0)
start = torch.cat((torch.tensor([0], device="cuda"), len_cumsum[:-1]), 0)
end = start + seq_lens - 2
start.clamp_(min=0, max=logprobs.shape[0] - 1)
end.clamp_(min=0, max=logprobs.shape[0] - 1)
sum_logp = logprobs_cumsum[end] - logprobs_cumsum[start] + logprobs[start]
# assert logprobs == [2, _, 2, 4, _]
print("logprobs", logprobs)
print("start", start)
print("end", end)
print("sum_logp", sum_logp)