refine the implementation of megatron and mocked dataset

internlm/data/build_dataloader.py

@@ -155,6 +155,9 @@ def get_streaming_train_loader_items(data_cfg):
 
 
 def get_megatron_train_loader_items(data_cfg):
+    assert data_cfg.get(
+        "pack_sample_into_one", False
+    ), "megatron dataloader curently only supports pack_sample_into_one=True"
     try:
         from internlm.data.megatron import helpers  # noqa # pylint: disable=W0611
     except ImportError:
@@ -174,14 +177,14 @@ def get_megatron_train_loader_items(data_cfg):
                     "internlm/data/megatron/helpers.so",
                 ]
             )
+
+    # NOTICE: Currently we only support single megatron dataset, a.k.a., single .bin and .idx
+    # Megatron dataset (.bin and.idx) should be generated by Megatron-LM tools/preprocess_data.py
+    # https://github.com/NVIDIA/Megatron-LM/blob/main/tools/preprocess_data.py
     train_ds = build_megatron_dataset(
         data_prefix=data_cfg.train_folder,
-        data_impl=data_cfg.get("data_impl", "infer"),
-        splits_string="1.0, 0.0, 0.0",
-        train_valid_test_num_samples=[9600000, 0, 0],
         seq_len=data_cfg.seq_len,
         seed=data_cfg.get("seed", 1024),
-        skip_warmup=True,
     )
 
     train_sampler = MegatronBatchSampler(
@@ -202,14 +205,18 @@ def get_mock_train_loader_items(data_cfg):
     assert data_cfg.get(
         "pack_sample_into_one", False
     ), "mocked dataloader curently only supports pack_sample_into_one=True"
+
     train_ds = MockedDataset(
         train_folder=data_cfg.train_folder,
         micro_bsz=data_cfg.micro_bsz,
         micro_num=data_cfg.micro_num,
         seq_len=data_cfg.seq_len,
     )
+
     train_sampler = MockedSequentialBatchSampler(train_ds, data_cfg.micro_num)
+
     train_collate_fn = partial(packed_collate_fn, packed_length=data_cfg.seq_len * data_cfg.micro_bsz)
+
     return train_ds, train_sampler, train_collate_fn
 
 

internlm/data/megatron/batch_sampler.py

@@ -57,6 +57,6 @@ def __iter__(self):
             start_idx, end_idx = self.get_start_end_idx()
             yield batch[start_idx:end_idx]
 
-    # TODO: implement copy method that compatible with InternEvo trainstate
+    # TODO: implement copy method that compatible with InternEvo trainstate ckpt save and load.
     def copy(self):
         return copy.deepcopy(self)

internlm/data/megatron/collaters.py

@@ -2,48 +2,36 @@
 
 
 def megatron_collate_fn(batch, micro_num, micro_bsz, seq_len):
-
-    input_ids_result = [[] for _ in range(micro_num)]
-    labels_result = [[] for _ in range(micro_num)]
-    cu_seqlens = []
+    input_ids_list = [[] for _ in range(micro_num)]
+    labels_list = [[] for _ in range(micro_num)]
     cu_seqlens_list = []
-    indexes = []
     indexes_list = []
 
-    for i, item in enumerate(batch):
-        assert i < micro_num * micro_bsz
-        seq_len_list = item["text"]
-        assert len(seq_len_list) == seq_len + 1
-
-        micro_bsz_index = i % micro_bsz
-        micro_num_index = i // micro_bsz
-
-        input_ids_result[micro_num_index].append(seq_len_list[:-1])
-        labels_result[micro_num_index].append(seq_len_list[1:])
-
-        cu_seqlens.append(seq_len * micro_bsz_index)
-        indexes = indexes + list(range(seq_len))
+    assert len(batch) == micro_bsz * micro_num
+    for idx, b in enumerate(batch):
+        tokens = b["text"]
+        # The length of megatron preprocessed data samples is (seq_len + 1)
+        # So we use the first seq_len tokens as input and the last seq_len tokens as shifted labels
+        assert len(tokens) == seq_len + 1
+        micro_bsz_index = idx % micro_bsz
+        micro_num_index = idx // micro_bsz
+        input_ids_list[micro_num_index].append(tokens[:-1])
+        labels_list[micro_num_index].append(tokens[1:])
 
         if micro_bsz_index == micro_bsz - 1:
-            input_ids_result[micro_num_index] = torch.cat(
-                [torch.from_numpy(arr).long() for arr in input_ids_result[micro_num_index]], dim=0
+            # Since megatron data sample is numpy format, we need to convert it to tensor and concate within micro batch
+            input_ids_list[micro_num_index] = torch.cat(
+                [torch.from_numpy(arr) for arr in input_ids_list[micro_num_index]], dim=0
             )
-            labels_result[micro_num_index] = torch.cat(
-                [torch.from_numpy(arr).long() for arr in labels_result[micro_num_index]], dim=0
+            labels_list[micro_num_index] = torch.cat(
+                [torch.from_numpy(arr) for arr in labels_list[micro_num_index]], dim=0
             )
-            cu_seqlens.append(seq_len * micro_bsz)
-            cu_seqlens_list.append(torch.IntTensor(cu_seqlens))
-            cu_seqlens = []
-            indexes_list.append(torch.IntTensor(indexes))
-            indexes = []
-
-    input_ids = torch.stack(input_ids_result)
-    labels = torch.stack(labels_result)
-    indexes = torch.stack(indexes_list)
+            cu_seqlens_list.append(torch.IntTensor([i * seq_len for i in range(micro_bsz + 1)]))
+            indexes_list.append(torch.IntTensor(list(range(seq_len)) * micro_bsz))
 
     return {
-        "input_ids": input_ids,
+        "input_ids": torch.stack(input_ids_list),
         "cu_seqlens": cu_seqlens_list,
-        "indexes": indexes,
+        "indexes": torch.stack(indexes_list),
         "type_ids": torch.zeros(micro_num, micro_bsz * seq_len, dtype=torch.int64),
-    }, labels
+    }, torch.stack(labels_list)

internlm/data/megatron/dataset.py

@@ -1,5 +1,6 @@
 # adapted from https://github.com/NVIDIA/Megatron-LM/blob/main/megatron/core/datasets/gpt_dataset.py
 # adapted from https://github.com/NVIDIA/Megatron-LM/blob/main/megatron/core/datasets/indexed_dataset.py
+
 import hashlib
 import os
 import struct
@@ -764,82 +765,25 @@ def get_indexed_dataset_(data_prefix, data_impl, skip_warmup):
     return indexed_dataset
 
 
-def get_train_valid_test_split_(splits_string, size):
-    """Get dataset splits from comma or '/' separated string list."""
-
-    splits = []
-    if splits_string.find(",") != -1:
-        splits = [float(s) for s in splits_string.split(",")]
-    elif splits_string.find("/") != -1:
-        splits = [float(s) for s in splits_string.split("/")]
-    else:
-        splits = [float(splits_string)]
-    while len(splits) < 3:
-        splits.append(0.0)
-    splits = splits[:3]
-    splits_sum = sum(splits)
-    assert splits_sum > 0.0
-    splits = [split / splits_sum for split in splits]
-    splits_index = [0]
-    for index, split in enumerate(splits):
-        splits_index.append(splits_index[index] + int(round(split * float(size))))
-    diff = splits_index[-1] - size
-    for index in range(1, len(splits_index)):
-        splits_index[index] -= diff
-    assert len(splits_index) == 4
-    assert splits_index[-1] == size
-    return splits_index
-
-
 def build_megatron_dataset(
     data_prefix,
-    data_impl,
-    splits_string,
-    train_valid_test_num_samples,
     seq_len,
     seed,
-    skip_warmup,
-    return_doc_ids=False,
-    *,
-    data_cache_path=None,
 ):
-
     # Indexed dataset.
-    indexed_dataset = get_indexed_dataset_(data_prefix, data_impl, skip_warmup)
-
-    total_num_of_documents = indexed_dataset.sizes.shape[0]
-    splits = get_train_valid_test_split_(splits_string, total_num_of_documents)
-
-    # Print stats about the splits.
-    print_rank_0(" > dataset split:")
-
-    def print_split_stats(index, name):
-        print_rank_0("    {}:".format(name))
-        print_rank_0(
-            "     document indices in [{}, {}) total of {} "
-            "documents".format(splits[index], splits[index + 1], splits[index + 1] - splits[index])
-        )
-
-    print_split_stats(0, "train")
-
-    def build_dataset(index, name):
-        dataset = None
-        if splits[index + 1] > splits[index]:
-            documents = np.arange(start=splits[index], stop=splits[index + 1], step=1, dtype=np.int32)
-            dataset = GPTDataset(
-                name,
-                data_prefix,
-                documents,
-                indexed_dataset,
-                splits_string,
-                train_valid_test_num_samples[index],
-                seq_len,
-                seed,
-                return_doc_ids,
-                data_cache_path=data_cache_path,
-            )
-        return dataset
-
-    train_dataset = build_dataset(0, "train")
-
-    return train_dataset
+    indexed_dataset = get_indexed_dataset_(data_prefix, data_impl="infer", skip_warmup=True)
+
+    # GPT dataset.
+    return GPTDataset(
+        name="train",
+        data_prefix=data_prefix,
+        documents=np.arange(start=0, stop=indexed_dataset.sizes.shape[0], step=1, dtype=np.int32),
+        indexed_dataset=indexed_dataset,
+        splits_string="1.0, 0.0, 0.0",  # proportion of dataset for train/valid/test, we set 1.0 for train only
+        num_samples=gpc.config.data.micro_bsz
+        * gpc.config.data.micro_num
+        * gpc.get_world_size(ParallelMode.DATA)
+        * gpc.config.data.total_steps,  # total number of train samples
+        seq_length=seq_len,
+        seed=seed,
+    )

internlm/data/mocked/batch_sampler.py

@@ -19,6 +19,6 @@ def __iter__(self):
     def __len__(self):
         return (len(self.train_ds) + self.micro_num - 1) // self.micro_num
 
-    # TODO: implement copy method that compatible with InternEvo trainstate
+    # TODO: implement copy method that compatible with InternEvo trainstate ckpt save and load.
     def copy(self):
         return copy.deepcopy(self)