working on masking fix

This commit is contained in:
Dan Saunders
2025-04-04 20:24:18 +00:00
parent 9b89591ead
commit 4188700b7b
3 changed files with 97 additions and 12 deletions

View File

@@ -22,6 +22,60 @@ except ImportError:
pass
def calculate_cu_seqlens(position_ids: torch.Tensor, total_seq_len: int) -> torch.Tensor:
# Must be batch size 1
position_ids = position_ids.flatten()
LOG.info(f"position_ids: {position_ids}")
# Find where the position resets to 0 (indicating a new sequence)
# We add position_ids.new_ones(1) to mark the start of the first sequence
sequence_starts = torch.cat([position_ids.new_ones(1), (position_ids[1:] == 0).to(torch.int)])
# Get all indices where sequence_starts
potential_indices = torch.nonzero(sequence_starts).flatten()
# Filter out indices where the next index also has a zero
valid_indices = []
for i in range(len(potential_indices)):
# Get current index position in the original tensor
current_pos = potential_indices[i]
# Check if this is the last index or if the next element is not a zero
if i == len(potential_indices) - 1:
continue
elif potential_indices[i + 1] != current_pos + 1:
valid_indices.append(current_pos)
start_indices = torch.tensor(valid_indices, device=potential_indices.device)
LOG.info(f"start_indices: {start_indices}")
# Calculate individual sequence lengths
if len(start_indices) > 1:
sequence_lengths = torch.diff(start_indices, append=torch.tensor([len(position_ids)]))
else:
sequence_lengths = torch.tensor([len(position_ids)])
LOG.info(f"sequence_lengths: {sequence_lengths}")
# Calculate cumulative sequence lengths
cu_seqlens = torch.cumsum(
sequence_lengths.to(torch.cuda.current_device()),
dim=0,
dtype=torch.int32,
)
LOG.info(f"cu_seqlens: {cu_seqlens}")
cu_seqlens = F.pad(F.pad(cu_seqlens, (1, 0), value=0), (0, 1), value=total_seq_len)
LOG.info(f"cu_seqlens with padding: {cu_seqlens}")
import torch.distributed as dist
if dist.get_rank() == 1:
import ipdb; ipdb.set_trace()
dist.barrier()
return cu_seqlens
class SequenceParallelMixin:
"""
Mixin class for sequence parallelism support in trainers.
@@ -118,17 +172,42 @@ class SequenceParallelMixin:
# Calculate the full sequence length across all GPUs in this SP group
total_seq_len = seq_len * self.args.sequence_parallel_degree
cu_seqlens = torch.cumsum(
torch.tensor(
packed_seq_lens, device=torch.cuda.current_device(), dtype=torch.int32
),
dim=-1,
dtype=torch.int32,
)
cu_seqlens = F.pad(
F.pad(cu_seqlens, (1, 0), value=0), (0, 1), value=total_seq_len
)
# cu_seqlens = torch.cumsum(
# torch.tensor(
# packed_seq_lens, device=torch.cuda.current_device(), dtype=torch.int32
# ),
# dim=-1,
# dtype=torch.int32,
# )
# cu_seqlens = F.pad(
# F.pad(cu_seqlens, (1, 0), value=0), (0, 1), value=total_seq_len
# )
# packed_seq_lens = []
# current_len = 1 # Start counting the first token
# # Iterate through position IDs starting from the second element
# for i in range(1, len(inputs["position_ids"])):
# # If current position is less than previous, it's a new sequence
# if inputs["position_ids"][i] < inputs["position_ids"][i - 1]:
# packed_seq_lens.append(current_len)
# current_len = 1
# else:
# current_len += 1
# # Add the last sequence length
# packed_seq_lens.append(current_len)
# LOG.info(f"{packed_seq_lens}: packed_seq_lens")
# cu_seqlens = torch.cumsum(
# torch.tensor(packed_seq_lens, device=torch.cuda.current_device(), dtype=torch.int32),
# dim=-1,
# dtype=torch.int32,
# )
# cu_seqlens = F.pad(F.pad(cu_seqlens, (1, 0), value=0), (0, 1), value=total_seq_len)
# LOG.info(f"{cu_seqlens}: cu_seqlens")
cu_seqlens = calculate_cu_seqlens(inputs["position_ids"], total_seq_len)
update_ring_flash_attn_params(cu_seqlens, self.ring_attn_group)
def training_step(

View File

@@ -211,8 +211,8 @@ class DataCollatorForSeq2Seq:
batch[key] = batch[key][:, start_idx:end_idx]
# Special handling for position_ids
if key == "position_ids" and self.local_rank > 0:
batch[key] = adjust_position_ids_for_slice(batch[key], start_idx)
# if key == "position_ids" and self.local_rank > 0:
# batch[key] = adjust_position_ids_for_slice(batch[key], start_idx)
return batch

View File

@@ -1155,6 +1155,12 @@ class AxolotlInputConfig(
raise ValueError(
"flash_attention: true must be set with sequence_parallel_degree > 1"
)
if not info.data["micro_batch_size"] == 1:
raise ValueError(
"micro_batch_size must be set to 1 "
"due to a `ring-flash-attn` requirement"
)
try:
import ring_flash_attn # noqa: F401 # pylint:disable=unused-import