infra/4-training/nemo-example/selected-configuration.yaml

#  Copyright 2024 Google LLC

#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at

#       https://www.apache.org/licenses/LICENSE-2.0

#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

run:
  name: GPT-5B

trainer:
  devices: 8
  accelerator: gpu
  precision: bf16
  logger: false  # logger provided by exp_manager
  enable_checkpointing: false
  # replace_sampler_ddp: false
  use_distributed_sampler: false
  max_epochs: null
  max_steps: 50  # consumed_samples = global_step * global_batch_size
  max_time: "05:00:00:00"
  log_every_n_steps: 1
  val_check_interval: 50
  limit_val_batches: 0.0
  limit_test_batches: 10
  accumulate_grad_batches: 1
  gradient_clip_val: 1.0
  # enable_progress_bar: true

exp_manager:
  explicit_log_dir: null
  name: megatron_gpt
  create_wandb_logger: false
  wandb_logger_kwargs:
    project: null
    name: null
  resume_if_exists: true
  resume_ignore_no_checkpoint: true
  create_checkpoint_callback: true
  checkpoint_callback_params:
    monitor: val_loss
    save_top_k: 10
    mode: min
    always_save_nemo: false  # saves nemo file during validation, not implemented for model parallel
    save_nemo_on_train_end: false  # not recommended when training large models on clusters with short time limits
    filename: 'megatron_gpt--{val_loss:.2f}-{step}-{consumed_samples}'
    model_parallel_size: ${multiply:${model.tensor_model_parallel_size}, ${model.pipeline_model_parallel_size}}
  log_step_timing: true
  step_timing_kwargs:
    sync_cuda: true
    buffer_size: 5

model:
  micro_batch_size: 4
  global_batch_size: 2048
  rampup_batch_size: null  
  tensor_model_parallel_size: 1
  pipeline_model_parallel_size: 1
  virtual_pipeline_model_parallel_size: null  # interleaved pipeline
  resume_from_checkpoint: null  # manually set the checkpoint file to load from

  # model architecture
  encoder_seq_length: 2048
  max_position_embeddings: 2048
  num_layers: 24
  hidden_size: 4096
  ffn_hidden_size: ${multiply:4, ${.hidden_size}}  # Transformer FFN hidden size. 4 * hidden_size.
  num_attention_heads: 32
  init_method_std: 0.01  # Standard deviation of the zero mean normal distribution used for weight initialization.')
  hidden_dropout: 0.0  # Dropout probability for hidden state transformer.
  attention_dropout: 0.0
  kv_channels: null  # Projection weights dimension in multi-head attention. Set to hidden_size // num_attention_heads if null
  apply_query_key_layer_scaling: true  # scale Q * K^T by 1 / layer-number.
  layernorm_epsilon: 1e-5
  make_vocab_size_divisible_by: 128  # Pad the vocab size to be divisible by this value for computation efficiency.
  pre_process: true  # add embedding
  post_process: true  # add pooler
  persist_layer_norm: true  # Use of persistent fused layer norm kernel.
  gradient_as_bucket_view: true  # Allocate gradients in a contiguous bucket to save memory (less fragmentation and buffer memory)

  # Fusion
  grad_div_ar_fusion: true  # Fuse grad division into torch.distributed.all_reduce
  gradient_accumulation_fusion: true  # Fuse weight gradient accumulation to GEMMs
  bias_activation_fusion: true  # Use a kernel that fuses the bias addition from weight matrices with the subsequent activation function.
  bias_dropout_add_fusion: true  # Use a kernel that fuses the bias addition, dropout and residual connection addition.
  masked_softmax_fusion: true  # Use a kernel that fuses the attention softmax with it's mask.

  ## Activation Checkpointing
  activations_checkpoint_granularity: null  # 'selective' or 'full'
  activations_checkpoint_method: null  # 'uniform', 'block'
  activations_checkpoint_num_layers: null
  num_micro_batches_with_partial_activation_checkpoints: null
  activations_checkpoint_layers_per_pipeline: null

  ## Sequence Parallelism
  sequence_parallel: false

  overlap_p2p_comm: false # Overlap p2p communication with computes. This argument is valid only when `virtual_pipeline_model_parallel_size` is larger than 1
  batch_p2p_comm: true # Batch consecutive inter-peer send/recv operations. This argument is valid only when `virtual_pipeline_model_parallel_size` is larger than 1
  num_query_groups: null # Number of query groups for group query attention. If None, normal attention is used.

  tokenizer:
    library: 'megatron'
    type: 'GPT2BPETokenizer'
    model: null
    delimiter: null  # only used for tabular tokenizer
    vocab_file: gpt2-vocab.json
    merge_file: gpt2-merges.txt

  # precision
  native_amp_init_scale: 4294967296  # 2 ** 32
  native_amp_growth_interval: 1000
  hysteresis: 2  # Gradient scale hysteresis
  fp32_residual_connection: false  # Move residual connections to fp32
  fp16_lm_cross_entropy: false  # Move the cross entropy unreduced loss calculation for lm head to fp16

  # Megatron O2-style half-precision
  megatron_amp_O2: true  # Enable O2-level automatic mixed precision using master parameters
  grad_allreduce_chunk_size_mb: 125

  mcore_gpt: true
  
  ## Transformer Engine
  # To use fp8, please set `transformer_engine=true` and `fp8=true`.
  # The rest of fp8 knobs are set for the fp8 training mode, which are ignored in non-fp8 training
  transformer_engine: true
  fp8: false  # enables fp8 in TransformerLayer forward
  fp8_e4m3: false  # sets fp8_format = recipe.Format.E4M3
  fp8_hybrid: true  # sets fp8_format = recipe.Format.HYBRID
  fp8_margin: 0  # scaling margin
  fp8_interval: 1  # scaling update interval
  fp8_amax_history_len: 1024  # Number of steps for which amax history is recorded per tensor
  fp8_amax_compute_algo: max  # 'most_recent' or 'max'. Algorithm for computing amax from history
  fp8_wgrad: true
  # use_emha: false
  ub_tp_comm_overlap: false

  # miscellaneous
  seed: 1234
  sync_batch_comm: false
  use_cpu_initialization: false  # Init weights on the CPU (slow for large models)
  onnx_safe: false  # Use work-arounds for known problems with Torch ONNX exporter.
  apex_transformer_log_level: 30  # Python logging level displays logs with severity greater than or equal to this

  # Nsys profiling options
  nsys_profile:
    enabled: false
    trace: [nvtx, cuda]
    start_step: 10  # Global batch to start profiling
    end_step: 12  # Global batch to end profiling
    ranks: [0]  # Global rank IDs to profile
    gen_shape: false  # Generate model and kernel details including input shapes

  optim:
    name: distributed_fused_adam
    bucket_cap_mb: 400
    overlap_grad_sync: true
    overlap_param_sync: true
    contiguous_grad_buffer: true
    # grad_sync_dtype: bf16
    lr: 1.6e-4
    weight_decay: 0.1
    betas:
    - 0.9
    - 0.95
    sched:
      name: CosineAnnealing
      warmup_steps: 115
      constant_steps: 12500
      min_lr: 1.6e-5

  data:
    exchange_indices_distributed: true
    data_impl: mmap
    splits_string: "99990,8,2"
    seq_length: 2048
    skip_warmup: true
    num_workers: 2
    dataloader_type: single  # cyclic
    reset_position_ids: false  # Reset position ids after end-of-document token
    reset_attention_mask: false  # Reset attention mask after end-of-document token
    eod_mask_loss: false  # Mask loss for the end of document tokens
    # index_mapping_dir: null  # path to save index mapping .npy files, by default will save in the same location as data_prefix
    index_mapping_dir: /nfs