Attention mask and position id fixes for packing (#285)

* fix attetion mask with packing

* set position ids and use block diagonal attn mask

* fix expand mask for multiple batch items, make sure we pad position_ids

* don't move masks to cpu

* use multi pack dataloader w random sampler

* add position_ids back

* more fixes for dataloader integration

* est total tokens, fix field loop

* more fixes, position_ids seems broken

* more fixes for sample packing

* use distributed sampler, avoid accelerate prepare

* use accelerator prepare for dataloader

* fix for position_ids w packing

* Update src/axolotl/utils/dataloader.py

* validation for sample packing and doc

* more fixes for 4k and optimizations

* optimized expand mask fn

* better handling of variance in multipack dataloader length and trainer hanging when it runs out of data

* fix rounding of len of batches to int

* better handling so that all devices have the same dataloader len

* fix step calc for packing

* pass sample packing efficiency to training args

* add a test for the mask expansion for sequence packing

* only process eval dataset for packing if not None

* don't split batches when packing

* weighted CE losses

* weighted CEL fixes

* limit packing to sequences of max seq len

* seq_len_multiple for packing

* make sure the chunk size is an int

* sample_packing_seq_len_multiplier config

* use cumulative seq len with var len flash attn v2 w packing

* properly calculate max len

* fix flash-attn, xformers, packing, support chatml

* fix chatml system prompt for openorca, legacy tokenizer opts

* add chatml

* add unit tests for cum seq lens, add ability to build cu_seq_lens from positional ids, fix prompt test

* fix test and pylint checks

* more packing and dataset optimizations and fixes

* filter w multiple cpus

* more fixes and optimizations

* fixes and go back to distributed sampler since batch sampler won't work

* fix counts by accounting for num devices

* fix steps calculation

* previous accelerate is still most performant

* add numba to requirements.

* use custom distributed checks

* fix sampler to prevent overfit w new epochs

* let's not cleanup the cached datasets

* calculate cum seq lens with pos_ids instead of mask, simplify packing params, fix distributed barrier

* speed optimizations and set accelerate fsdp env vars

* optimize dataset concatenation?

* more optimizations for dataset handling

* fix import for annotation

* manual pre-commit fixes

* another sum optimization and bug fix for calc steps

* fix packing estimations

* fix formatting

* pylint problems

* add back flash attention branch for handling unpacked sequences seperately

* Address PR feedback

* add optional sample packing config params to readme

README.md

@@ -375,7 +375,14 @@ dataset_shard_idx:
 sequence_len: 2048
 # max sequence length to concatenate training samples together up to
 # inspired by StackLLaMA. see https://huggingface.co/blog/stackllama#supervised-fine-tuning
+# FutureWarning: This will soon be DEPRECATED
 max_packed_sequence_len: 1024
+# use efficient multi-packing with block diagonal attention and per sequence position_ids. Recommend set to 'true'
+sample_packing:
+# you can set these packing optimizations AFTER starting a training at least once.
+# The trainer will provide recommended values for these values.
+sample_packing_eff_est:
+total_num_tokens:
 
 # if you want to use 'lora' or 'qlora' or leave blank to train all parameters in original model
 adapter: lora
@@ -421,6 +428,7 @@ learning_rate: 0.00003
 logging_steps:
 save_steps:
 eval_steps:
+save_total_limit:
 
 # save model as safetensors (require safetensors package)
 save_safetensors:
@@ -534,7 +542,7 @@ accelerate launch scripts/finetune.py configs/your_config.yml
 
 #### Multi-GPU
 
-It is recommended to pre-tokenize dataset with the following before finetuning:
+You can optionally pre-tokenize dataset with the following before finetuning:
 ```bash
 CUDA_VISIBLE_DEVICES="" accelerate ... --prepare_ds_only
 ```