PoSE context length ext (#1567)

* PoSE wip

* fixes for pose splitting

* set pose context len so we can pick that up seperately from the usable training context len

* support min sample len and define num chunks

* fix chunk splitting

* support for curriculum/ordered learning with pose

* fix sequence len sort

* add curriculum_sampling to pydantic

src/axolotl/core/trainer_builder.py

@@ -212,6 +212,10 @@ class AxolotlTrainingArguments(TrainingArguments):
         default=None,
         metadata={"help": "path under the model to access the layers"},
     )
+    curriculum_sampling: Optional[bool] = field(
+        default=None,
+        metadata={"help": "whether to use sequential sampling for curriculum learning"},
+    )
 
 
 class AxolotlTrainer(Trainer):
@@ -347,6 +351,8 @@ def _get_train_sampler(self) -> Optional[torch.utils.data.Sampler]:
                 lengths=get_dataset_lengths(self.train_dataset),
                 packing_efficiency_estimate=self.args.sample_packing_efficiency,
             )
+        if self.args.curriculum_sampling:
+            return SequentialSampler(self.train_dataset)
         return super()._get_train_sampler()
 
     def _get_eval_sampler(
@@ -1193,6 +1199,7 @@ def build(self, total_num_steps):
             False if self.cfg.ddp else None
         )
         training_arguments_kwargs["group_by_length"] = self.cfg.group_by_length
+        training_arguments_kwargs["curriculum_sampling"] = self.cfg.curriculum_sampling
         report_to = None
         if self.cfg.use_wandb:
             report_to = "wandb"

src/axolotl/utils/config/models/input/v0_4_1/__init__.py

@@ -503,9 +503,17 @@ class Config:
     unfrozen_parameters: Optional[List[str]] = None
 
     sequence_len: int = Field(default=512)
+    min_sample_len: Optional[int] = None
     sample_packing: Optional[bool] = None
     eval_sample_packing: Optional[bool] = None
     pad_to_sequence_len: Optional[bool] = None
+    curriculum_sampling: Optional[bool] = None
+
+    # for PoSE context length extension
+    use_pose: Optional[bool] = None
+    pose_split_on_token_ids: Optional[List[int]] = None
+    pose_max_context_len: Optional[int] = None
+    pose_num_chunks: Optional[int] = None
 
     pretrain_multipack_buffer_size: Optional[int] = 10_000
     pretrain_multipack_attn: Optional[bool] = Field(

src/axolotl/utils/trainer.py

@@ -1,9 +1,10 @@
 """Module containing the Trainer class and related functions"""
 import math
 import os
+import random
 from contextlib import contextmanager
 from functools import partial
-from typing import List
+from typing import List, Optional
 
 import numpy as np
 import torch
@@ -98,17 +99,89 @@ def add_position_ids(sample):
     return sample
 
 
+def add_pose_position_ids(
+    sample,
+    max_context_len=32768,
+    split_on_token_ids: Optional[List[int]] = None,
+    chunks: int = 2,
+):
+    """
+    use the PoSE technique to extend the context length by randomly skipping
+    positions in the context. We only want to skip right before tokens in
+    the split_on_token_ids list. We should attempt to randomly distribute
+    the skips, but we don't need the final position_ids to be the full
+    context_len. There may be multiple turns in the context, so we want to
+    make sure we take into account the maximum possible number of skips
+    remaining in each sample.
+    """
+
+    input_ids = sample["input_ids"]
+    sample_len = len(input_ids)
+    max_skips = max_context_len - sample_len
+
+    if split_on_token_ids is None:
+        split_on_token_ids = []
+
+    if split_on_token_ids:
+        split_indices = [
+            i for i, token_id in enumerate(input_ids) if token_id in split_on_token_ids
+        ]
+    else:
+        chunk_len = sample_len // chunks
+        split_indices = [i * chunk_len for i in range(1, chunks)]
+    split_indices.append(len(input_ids))  # make sure we go to the end of the sample
+    if split_indices[0] < 2:
+        # drop the first split index if it's too close to the beginning
+        split_indices = split_indices[1:]
+
+    position_ids = []
+    prev_index = 0
+    total_skips = 0
+
+    for split_index in split_indices:
+        num_skips = (
+            random.randint(0, max_skips)  # nosec B311
+            if prev_index != 0 and max_skips
+            else 0
+        )
+        max_skips -= num_skips
+        total_skips += num_skips
+
+        segment_position_ids = list(
+            range(prev_index + total_skips, split_index + total_skips)
+        )
+
+        position_ids.extend(segment_position_ids)
+        prev_index = split_index
+
+    sample["sequence_len"] = position_ids[-1]
+    position_ids = torch.tensor(position_ids)
+
+    sample["position_ids"] = position_ids
+    sample["length"] = len(position_ids)
+    assert len(position_ids) == len(input_ids)
+
+    return sample
+
+
 def add_length(sample):
     sample["length"] = len(sample["input_ids"])
     return sample
 
 
-def drop_long_seq(sample, sequence_len=2048):
-    return len(sample["input_ids"]) <= sequence_len and len(sample["input_ids"]) > 0
+def drop_long_seq(sample, sequence_len=2048, min_sequence_len=2):
+    return (
+        len(sample["input_ids"]) <= sequence_len
+        and len(sample["input_ids"]) >= min_sequence_len
+    )
 
 
 def process_datasets_for_packing(cfg, train_dataset, eval_dataset):
-    drop_long = partial(drop_long_seq, sequence_len=cfg.sequence_len)
+    drop_long = partial(
+        drop_long_seq,
+        sequence_len=cfg.sequence_len,
+        min_sequence_len=cfg.min_sample_len or 2,
+    )
     with zero_first(is_main_process()):
         if cfg.is_preprocess:
             min_input_len = np.min(get_dataset_lengths(train_dataset))
@@ -153,7 +226,32 @@ def process_datasets_for_packing(cfg, train_dataset, eval_dataset):
                 desc="Group By Length",
             )
 
-        if cfg.sample_packing:
+        if cfg.use_pose:
+            pose_kwargs = {}
+            if cfg.pose_num_chunks is not None:
+                pose_kwargs["chunks"] = cfg.pose_num_chunks
+            pose_fn = partial(
+                add_pose_position_ids,
+                max_context_len=cfg.pose_max_context_len,
+                split_on_token_ids=cfg.pose_split_on_token_ids,
+                **pose_kwargs,
+            )
+            train_dataset = train_dataset.map(
+                pose_fn,
+                num_proc=cfg.dataset_processes,
+                load_from_cache_file=not cfg.is_preprocess,
+                desc="Add position_id column (PoSE)",
+            )
+            train_dataset = train_dataset.sort("sequence_len")
+            if cfg.eval_sample_packing is not False:
+                if eval_dataset:
+                    eval_dataset = eval_dataset.map(
+                        pose_fn,
+                        num_proc=cfg.dataset_processes,
+                        load_from_cache_file=not cfg.is_preprocess,
+                        desc="Add position_id column (PoSE)",
+                    )
+        elif cfg.sample_packing:
             train_dataset = train_dataset.map(
                 add_position_ids,
                 num_proc=cfg.dataset_processes,