vllm/vllm/model_executor/sampling_metadata.py
2024-03-25 07:59:47 -07:00

357 lines
14 KiB
Python

import random
from dataclasses import dataclass
from typing import Dict, List, Optional, Tuple
import torch
from vllm.model_executor.layers.ops.sample import get_num_triton_sampler_splits
from vllm.sampling_params import SamplingParams, SamplingType
from vllm.sequence import SequenceData
from vllm.utils import is_pin_memory_available
_SAMPLING_EPS = 1e-5
_SEED_0_REPLACEMENT = 3403598558
class SamplingMetadata:
"""Metadata for input sequences. Used in sampler.
Args:
seq_groups: List of (seq_ids, sampling_params).
seq_data: Seq_id -> SequenceData.
prompt_lens: Lengths of prompts.
selected_token_indices: Token indices selected for sampling.
categorized_sample_indices: SamplingType -> token indices to sample.
generators: List of torch.Generators to use for seeded sampling
perform_sampling: Whether to perform sampling. This option is used to
make the sampling only happens in the driver worker, and disable
sampling in other worker processes.
"""
def __init__(
self,
seq_groups: Optional[List[Tuple[List[int], SamplingParams]]],
seq_data: Optional[Dict[int, SequenceData]],
prompt_lens: Optional[List[int]],
selected_token_indices: torch.Tensor,
categorized_sample_indices: Optional[Dict[SamplingType, torch.Tensor]],
generators: Optional[List[torch.Generator]] = None,
perform_sampling: bool = True,
) -> None:
self.seq_groups = seq_groups
self.seq_data = seq_data
self.prompt_lens = prompt_lens
self.selected_token_indices = selected_token_indices
self.categorized_sample_indices = categorized_sample_indices
self.generators = generators
self.perform_sampling = perform_sampling
self.num_prompts = len(prompt_lens) if prompt_lens is not None else 0
def __repr__(self) -> str:
return (
"SamplingMetadata("
f"seq_groups={self.seq_groups}, "
f"seq_data={self.seq_data}, "
f"prompt_lens={self.prompt_lens}, "
f"selected_token_indices={self.selected_token_indices}, "
f"categorized_sample_indices={self.categorized_sample_indices}), "
f"perform_sampling={self.perform_sampling})")
@dataclass
class SamplingTensors:
"""Tensors for sampling."""
temperatures: torch.Tensor
top_ps: torch.Tensor
top_ks: torch.Tensor
min_ps: torch.Tensor
presence_penalties: torch.Tensor
frequency_penalties: torch.Tensor
repetition_penalties: torch.Tensor
sampling_seeds: torch.Tensor
sample_indices: torch.Tensor
extra_seeds: Optional[torch.Tensor]
prompt_tokens: torch.Tensor
output_tokens: torch.Tensor
@classmethod
def from_sampling_metadata(
cls,
sampling_metadata: "SamplingMetadata",
vocab_size: int,
device: torch.device,
dtype: torch.dtype,
*,
extra_seeds_to_generate: int = 0,
extra_entropy: Optional[Tuple[int, ...]] = None
) -> Tuple["SamplingTensors", bool, bool, bool]:
"""
extra_seeds_to_generate: extra seeds to generate using the
user-defined seed for each sequence.
extra_entropy: extra entropy to use when generating seeds.
"""
prompt_tokens: List[List[int]] = []
output_tokens: List[List[int]] = []
top_ks: List[int] = []
temperatures: List[float] = []
top_ps: List[float] = []
min_ps: List[float] = []
presence_penalties: List[float] = []
frequency_penalties: List[float] = []
repetition_penalties: List[float] = []
sampling_seeds: List[int] = []
sample_indices: List[int] = []
prompt_best_of: List[int] = []
do_penalties = False
do_top_p_top_k = False
do_min_p = False
# We need one base seed per Triton slice.
seeds_to_generate = (extra_seeds_to_generate +
get_num_triton_sampler_splits(vocab_size))
sample_indices_start_idx = 0
for i, seq_group in enumerate(sampling_metadata.seq_groups):
seq_ids, sampling_params = seq_group
temperature = sampling_params.temperature
p = sampling_params.presence_penalty
f = sampling_params.frequency_penalty
r = sampling_params.repetition_penalty
top_p = sampling_params.top_p
min_p = sampling_params.min_p
seed = sampling_params.seed
is_greedy = sampling_params.sampling_type == SamplingType.GREEDY
# k should not be greater than the vocab size.
top_k = min(sampling_params.top_k, vocab_size)
top_k = vocab_size if top_k == -1 else top_k
if temperature < _SAMPLING_EPS:
# NOTE: Zero temperature means deterministic sampling
# (i.e., greedy sampling or beam search).
# Set the temperature to 1 to avoid division by zero.
temperature = 1.0
if not do_top_p_top_k and (top_p < 1.0 - _SAMPLING_EPS
or top_k != vocab_size):
do_top_p_top_k = True
if not do_min_p and min_p > _SAMPLING_EPS:
do_min_p = True
if not do_penalties and (abs(p) >= _SAMPLING_EPS
or abs(f) >= _SAMPLING_EPS
or abs(r - 1.0) >= _SAMPLING_EPS):
do_penalties = True
if (i < sampling_metadata.num_prompts
and sampling_params.prompt_logprobs is not None):
# For tokens in the prompt that we only need to get
# their logprobs
prompt_len = sampling_metadata.prompt_lens[i]
temperatures += [temperature] * (prompt_len - 1)
top_ps += [top_p] * (prompt_len - 1)
top_ks += [top_k] * (prompt_len - 1)
min_ps += [min_p] * (prompt_len - 1)
presence_penalties += [0] * (prompt_len - 1)
frequency_penalties += [0] * (prompt_len - 1)
repetition_penalties += [1] * (prompt_len - 1)
prompt_tokens.extend([] for _ in range(prompt_len - 1))
output_tokens.extend([] for _ in range(prompt_len - 1))
for seq_id in seq_ids:
seq_data = sampling_metadata.seq_data[seq_id]
prompt_tokens.append(seq_data.prompt_token_ids)
output_tokens.append(seq_data.output_token_ids)
temperatures += [temperature] * len(seq_ids)
top_ps += [top_p] * len(seq_ids)
top_ks += [top_k] * len(seq_ids)
min_ps += [min_p] * len(seq_ids)
presence_penalties += [p] * len(seq_ids)
frequency_penalties += [f] * len(seq_ids)
repetition_penalties += [r] * len(seq_ids)
is_prompt = i < sampling_metadata.num_prompts
if is_prompt:
prompt_best_of.append(sampling_params.best_of)
prompt_len = sampling_metadata.prompt_lens[i]
if sampling_params.prompt_logprobs is not None:
# NOTE: the sampling position is the last token
# in the prompt
sample_indices_start_idx += prompt_len - 1
for seq_id in seq_ids:
seq_data = sampling_metadata.seq_data[seq_id]
extra_entropy = extra_entropy or ()
seq_seeds = cls._get_sequence_seeds(
seed,
seq_data.get_len(),
*extra_entropy,
seq_id,
seeds_to_generate=seeds_to_generate,
is_greedy=is_greedy)
sampling_seeds.append(seq_seeds)
sample_indices.append(sample_indices_start_idx)
sample_indices_start_idx += 1
sampling_tensors = SamplingTensors.from_lists(
temperatures, top_ps, top_ks, min_ps, presence_penalties,
frequency_penalties, repetition_penalties, sampling_seeds,
sample_indices, prompt_tokens, output_tokens, vocab_size,
extra_seeds_to_generate, device, dtype)
return (sampling_tensors, do_penalties, do_top_p_top_k, do_min_p)
@classmethod
def from_lists(cls, temperatures: List[float], top_ps: List[float],
top_ks: List[int], min_ps: List[float],
presence_penalties: List[float],
frequency_penalties: List[float],
repetition_penalties: List[float],
sampling_seeds: List[int], sample_indices: List[int],
prompt_tokens: List[List[int]],
output_tokens: List[List[int]], vocab_size: int,
extra_seeds_to_generate: int, device: torch.device,
dtype: torch.dtype) -> "SamplingTensors":
# Note that the performance will be very bad without
# pinned memory.
pin_memory = is_pin_memory_available()
prompt_max_len = max(len(tokens) for tokens in prompt_tokens)
prompt_padded_tokens = [
tokens + [vocab_size] * (prompt_max_len - len(tokens))
for tokens in prompt_tokens
]
output_max_len = max(len(tokens) for tokens in output_tokens)
output_padded_tokens = [
tokens + [vocab_size] * (output_max_len - len(tokens))
for tokens in output_tokens
]
temperatures_t = torch.tensor(
temperatures,
device="cpu",
dtype=dtype,
pin_memory=pin_memory,
)
top_ps_t = torch.tensor(
top_ps,
device="cpu",
dtype=dtype,
pin_memory=pin_memory,
)
min_ps_t = torch.tensor(
min_ps,
device="cpu",
dtype=dtype,
pin_memory=pin_memory,
)
presence_penalties_t = torch.tensor(
presence_penalties,
device="cpu",
dtype=dtype,
pin_memory=pin_memory,
)
frequency_penalties_t = torch.tensor(
frequency_penalties,
device="cpu",
dtype=dtype,
pin_memory=pin_memory,
)
repetition_penalties_t = torch.tensor(
repetition_penalties,
device="cpu",
dtype=dtype,
pin_memory=pin_memory,
)
top_ks_t = torch.tensor(
top_ks,
device="cpu",
dtype=torch.int,
pin_memory=pin_memory,
)
sample_indices_t = torch.tensor(
sample_indices,
device="cpu",
dtype=torch.long,
pin_memory=pin_memory,
)
prompt_tensor = torch.tensor(
prompt_padded_tokens,
device="cpu",
dtype=torch.long,
pin_memory=pin_memory,
)
output_tensor = torch.tensor(
output_padded_tokens,
device="cpu",
dtype=torch.long,
pin_memory=pin_memory,
)
# need to transpose and make contiguous to
# copy the tensor correctly.
# [batch_size, n_seeds] -> [n_seeds, batch_size]
sampling_seeds_t = torch.tensor(
sampling_seeds,
device="cpu",
dtype=torch.long,
pin_memory=pin_memory,
).T.contiguous()
# Because the memory is pinned, we can do non-blocking
# transfer to device.
# How many seeds the sample operation itself will need.
num_base_seeds = sampling_seeds_t.shape[0] - extra_seeds_to_generate
sampling_seeds_gpu = sampling_seeds_t.to(device=device,
non_blocking=True)
extra_seeds_gpu = sampling_seeds_gpu[num_base_seeds:]
if not extra_seeds_gpu.numel():
extra_seeds_gpu = None
sampling_seeds_gpu = sampling_seeds_gpu[:num_base_seeds]
return cls(
temperatures=temperatures_t.to(device=device, non_blocking=True),
top_ps=top_ps_t.to(device=device, non_blocking=True),
top_ks=top_ks_t.to(device=device, non_blocking=True),
min_ps=min_ps_t.to(device=device, non_blocking=True),
presence_penalties=presence_penalties_t.to(device=device,
non_blocking=True),
frequency_penalties=frequency_penalties_t.to(device=device,
non_blocking=True),
repetition_penalties=repetition_penalties_t.to(device=device,
non_blocking=True),
prompt_tokens=prompt_tensor.to(device=device, non_blocking=True),
output_tokens=output_tensor.to(device=device, non_blocking=True),
sampling_seeds=sampling_seeds_gpu,
sample_indices=sample_indices_t.to(device=device,
non_blocking=True),
extra_seeds=extra_seeds_gpu,
)
@staticmethod
def _get_sequence_seeds(
seed: int,
*extra_entropy: int,
seeds_to_generate: int,
is_greedy: bool,
):
"""Get `seeds_to_generate` child seeds from `seed` and extra entropy."""
if not is_greedy:
if seed is None:
randint_fn = random.randint
else:
generator = random.Random(str((seed, ) + extra_entropy))
randint_fn = generator.randint
lo, hi = torch.iinfo(torch.long).min, torch.iinfo(torch.long).max
# If the user/random sets seed = 0 but request should
# have sampling, we need to change it to something
# else. We use a constant in that case.
# This way we don't need to create and load a bool
# matrix in the sampling kernel, which reduces CPU
# overhead and latency.
seq_seeds = [
randint_fn(lo, hi) or _SEED_0_REPLACEMENT
for _ in range(seeds_to_generate)
]
else:
# For the kernel, seed == 0 means greedy decoding.
seq_seeds = [0] * seeds_to_generate
return seq_seeds