Add BigCode converters (#532)

flash_attn/models/bert.py

@@ -18,11 +18,16 @@ import torch.nn.functional as F
 from einops import rearrange
 from transformers import BertConfig, PretrainedConfig
 from transformers.models.bert.modeling_bert import (
-    BaseModelOutputWithPoolingAndCrossAttentions, BertForPreTrainingOutput)
-
-from flash_attn.bert_padding import (index_first_axis,
-                                     index_first_axis_residual, pad_input,
-                                     unpad_input)
+    BaseModelOutputWithPoolingAndCrossAttentions,
+    BertForPreTrainingOutput,
+)
+
+from flash_attn.bert_padding import (
+    index_first_axis,
+    index_first_axis_residual,
+    pad_input,
+    unpad_input,
+)
 from flash_attn.modules.block import Block
 from flash_attn.modules.embedding import BertEmbeddings
 from flash_attn.modules.mha import MHA
@@ -75,11 +80,15 @@ def create_mlp_cls(config, layer_idx=None, return_residual=False):
     inner_dim = config.intermediate_size
     fused_mlp = getattr(config, "fused_mlp", False)
     if fused_mlp:
-        assert config.hidden_act in ["gelu_new", "gelu_fast"], (
+        assert config.hidden_act in ["gelu_new", "gelu_fast", "gelu_pytorch_tanh"], (
             "fused_mlp only " "supports approximate gelu"
         )
     if not fused_mlp:
-        approximate = "tanh" if config.hidden_act in ["gelu_new", "gelu_fast"] else "none"
+        approximate = (
+            "tanh"
+            if config.hidden_act in ["gelu_new", "gelu_fast", "gelu_pytorch_tanh"]
+            else "none"
+        )
         mlp_cls = partial(
             Mlp,
             hidden_features=inner_dim,
@@ -232,7 +241,11 @@ class BertPredictionHeadTransform(nn.Module):
             raise ImportError("dropout_add_layer_norm is not installed")
         linear_cls = nn.Linear if not fused_bias_fc else FusedDense
         self.dense = linear_cls(config.hidden_size, config.hidden_size)
-        approximate = "tanh" if config.hidden_act in ["gelu_new", "gelu_fast"] else "none"
+        approximate = (
+            "tanh"
+            if config.hidden_act in ["gelu_new", "gelu_fast", "gelu_pytorch_tanh"]
+            else "none"
+        )
         self.transform_act_fn = nn.GELU(approximate=approximate)
         self.layer_norm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
 
@@ -334,7 +347,7 @@ class BertModel(BertPreTrainedModel):
         self.fused_dropout_add_ln = getattr(config, "fused_dropout_add_ln", False)
         if self.fused_dropout_add_ln and layer_norm is None:
             raise ImportError("dropout_add_layer_norm is not installed")
-        assert config.hidden_act in ["gelu", "gelu_new", "gelu_fast"]
+        assert config.hidden_act in ["gelu", "gelu_new", "gelu_fast", "gelu_pytorch_tanh"]
 
         self.embeddings = BertEmbeddings(
             config.hidden_size,

flash_attn/models/bigcode.py

+import math
+import re
+from collections import OrderedDict
+
+import torch
+import torch.nn.functional as F
+from transformers import GPT2Config, GPTBigCodeConfig, PretrainedConfig
+
+
+def remap_state_dict_hf_bigcode(state_dict, config: PretrainedConfig):
+    """
+    Map the state_dict of a Huggingface BigCode model to be flash_attn compatible.
+    """
+
+    # Word embedding and position embedding
+    def key_mapping_pos_emb(key):
+        return re.sub(r"^transformer.wpe.", "transformer.embeddings.position_embeddings.", key)
+
+    state_dict = OrderedDict((key_mapping_pos_emb(k), v) for k, v in state_dict.items())
+    word_embeddings = state_dict.pop("transformer.wte.weight")
+    # It's possible that vocab_size is padded to be a multiple of 8, for example.
+    pad_vocab_size_multiple = getattr(config, "pad_vocab_size_multiple", 1)
+    vocab_size = math.ceil(config.vocab_size / pad_vocab_size_multiple) * pad_vocab_size_multiple
+    state_dict["transformer.embeddings.word_embeddings.weight"] = F.pad(
+        word_embeddings, (0, 0, 0, vocab_size - word_embeddings.shape[0])
+    )
+    state_dict["lm_head.weight"] = state_dict["transformer.embeddings.word_embeddings.weight"]
+
+    # LayerNorm
+    def key_mapping_ln(key):
+        key = re.sub(r"^transformer.ln_f.(weight|bias)", r"transformer.ln_f.\1", key)
+        key = re.sub(
+            r"^transformer.h.(\d+).ln_(1|2).(weight|bias)",
+            r"transformer.layers.\1.norm\2.\3",
+            key,
+        )
+        return key
+
+    state_dict = OrderedDict((key_mapping_ln(k), v) for k, v in state_dict.items())
+
+    def key_mapping_mlp(key):
+        key = re.sub(
+            r"^transformer.h.(\d+).mlp.c_fc.weight",
+            r"transformer.layers.\1.mlp.fc1.weight",
+            key,
+        )
+        key = re.sub(
+            r"^transformer.h.(\d+).mlp.c_proj.weight",
+            r"transformer.layers.\1.mlp.fc2.weight",
+            key,
+        )
+        key = re.sub(
+            r"^transformer.h.(\d+).mlp.c_fc.bias",
+            r"transformer.layers.\1.mlp.fc1.bias",
+            key,
+        )
+        key = re.sub(
+            r"^transformer.h.(\d+).mlp.c_proj.bias",
+            r"transformer.layers.\1.mlp.fc2.bias",
+            key,
+        )
+        return key
+
+    state_dict = OrderedDict((key_mapping_mlp(k), v) for k, v in state_dict.items())
+
+    # TODO: add support for multi-head attention
+    assert config.multi_query, "Only multi-query attention is supported"
+
+    # Attention
+    for d in range(config.num_hidden_layers):
+        embed_dim = config.n_embd
+        head_dim = embed_dim // config.n_head
+
+        c_attn_weight = state_dict.pop(f"transformer.h.{d}.attn.c_attn.weight")
+        # with multi-query attention, the weights have shape (embed_dim, embed_dim + head_dim + head_dim)
+        # see https://github.com/huggingface/transformers/blob/95b374952dc27d8511541d6f5a4e22c9ec11fb24/src/transformers/models/gpt_bigcode/modeling_gpt_bigcode.py#L112
+        # see also https://github.com/ggerganov/ggml/blob/dd1d575956e54c5bdc07632f25506b3b1884dbd2/examples/starcoder/convert-hf-to-ggml.py#L183
+        # ((n_head + 2) * head_dim, embed_dim) -> (3 * n_heads * head_dim, hidden_dim)
+        q, k, v = torch.split(c_attn_weight, [embed_dim, head_dim, head_dim], dim=0)
+        # duplicate k, v along the first axis (head_dim, hidden_dim) -> (n_heads * head_dim, hidden_dim)
+        k = torch.tile(k, (config.n_head, 1))
+        v = torch.tile(v, (config.n_head, 1))
+        state_dict[f"transformer.layers.{d}.mixer.Wqkv.weight"] = torch.cat((q, k, v), dim=0)
+
+        # same deal with the bias
+        c_attn_bias = state_dict.pop(f"transformer.h.{d}.attn.c_attn.bias")
+        # ((n_head + 2) * head_dim, embed_dim) -> (3 * n_heads * head_dim, hidden_dim)
+        q, k, v = torch.split(c_attn_bias, [embed_dim, head_dim, head_dim], dim=0)
+        # duplicate k, v along the first axis (head_dim, hidden_dim) -> (n_heads * head_dim, hidden_dim)
+        k = torch.tile(k, (config.n_head,))
+        v = torch.tile(v, (config.n_head,))
+        state_dict[f"transformer.layers.{d}.mixer.Wqkv.bias"] = torch.cat((q, k, v), dim=0)
+
+    def key_mapping_attn(key):
+        key = re.sub(
+            r"^transformer.h.(\d+).attn.c_proj.weight",
+            r"transformer.layers.\1.mixer.out_proj.weight",
+            key,
+        )
+        key = re.sub(
+            r"^transformer.h.(\d+).attn.c_proj.bias",
+            r"transformer.layers.\1.mixer.out_proj.bias",
+            key,
+        )
+        return key
+
+    state_dict = OrderedDict((key_mapping_attn(k), v) for k, v in state_dict.items())
+
+    return state_dict
+
+
+def inv_remap_state_dict_hf_bigcode(state_dict, config: PretrainedConfig):
+    """
+    Map the state_dict of a flash_attn model to be Huggingface BigCode compatible.
+
+    This function is meant to be the inverse of remap_state_dict_hf_bigcode.
+    """
+
+    # Word embedding and position embeddings
+    def inv_key_mapping_pos_emb(key):
+        return re.sub(r"^transformer.embeddings.position_embeddings.", "transformer.wpe.", key)
+
+    state_dict = OrderedDict((inv_key_mapping_pos_emb(k), v) for k, v in state_dict.items())
+    word_embeddings = state_dict.pop("transformer.embeddings.word_embeddings.weight")
+
+    word_embeddings = word_embeddings[:, : config.vocab_size]
+    state_dict["transformer.wte.weight"] = word_embeddings
+    state_dict["lm_head.weight"] = word_embeddings
+
+    # LayerNorm
+    def inv_key_mapping_ln(key):
+        key = re.sub(r"^transformer.ln_f.(weight|bias)", r"transformer.ln_f.\1", key)
+        key = re.sub(
+            r"^transformer.layers.(\d+).norm(1|2).(weight|bias)",
+            r"transformer.h.\1.ln_\2.\3",
+            key,
+        )
+        return key
+
+    state_dict = OrderedDict((inv_key_mapping_ln(k), v) for k, v in state_dict.items())
+
+    # MLPs
+    def inv_key_mapping_mlp(key):
+        key = re.sub(
+            r"^transformer.layers.(\d+).mlp.fc1.weight",
+            r"transformer.h.\1.mlp.c_fc.weight",
+            key,
+        )
+        key = re.sub(
+            r"^transformer.layers.(\d+).mlp.fc2.weight",
+            r"transformer.h.\1.mlp.c_proj.weight",
+            key,
+        )
+        key = re.sub(
+            r"^transformer.layers.(\d+).mlp.fc1.bias",
+            r"transformer.h.\1.mlp.c_fc.bias",
+            key,
+        )
+        key = re.sub(
+            r"^transformer.layers.(\d+).mlp.fc2.bias",
+            r"transformer.h.\1.mlp.c_proj.bias",
+            key,
+        )
+        return key
+
+    state_dict = OrderedDict((inv_key_mapping_mlp(k), v) for k, v in state_dict.items())
+
+    # Attention
+    for d in range(config.num_hidden_layers):
+        embed_dim = config.n_embd
+        head_dim = embed_dim // config.n_head
+
+        Wqkv_weight = state_dict.pop(f"transformer.layers.{d}.mixer.Wqkv.weight")
+        q, k, v = torch.split(
+            Wqkv_weight, [embed_dim, head_dim * config.n_head, head_dim * config.n_head], dim=0
+        )
+        c_attn_weight = torch.cat((q, k[:head_dim], v[:head_dim]), dim=0)
+        state_dict[f"transformer.h.{d}.attn.c_attn.weight"] = c_attn_weight
+
+        # Same deal with the bias
+        Wqkv_bias = state_dict.pop(f"transformer.layers.{d}.mixer.Wqkv.bias")
+        q, k, v = torch.split(
+            Wqkv_bias, [embed_dim, head_dim * config.n_head, head_dim * config.n_head], dim=0
+        )
+        c_attn_bias = torch.cat((q, k[:head_dim], v[:head_dim]), dim=0)
+        state_dict[f"transformer.h.{d}.attn.c_attn.bias"] = c_attn_bias
+
+    def inv_key_mapping_attn(key):
+        key = re.sub(
+            r"^transformer.layers.(\d+).mixer.out_proj.weight",
+            r"transformer.h.\1.attn.c_proj.weight",
+            key,
+        )
+        key = re.sub(
+            r"^transformer.layers.(\d+).mixer.out_proj.bias",
+            r"transformer.h.\1.attn.c_proj.bias",
+            key,
+        )
+        return key
+
+    state_dict = OrderedDict((inv_key_mapping_attn(k), v) for k, v in state_dict.items())
+
+    return state_dict
+
+
+def bigcode_config_to_gpt2_config(bigcode_config: GPTBigCodeConfig) -> GPT2Config:
+    return GPT2Config(
+        activation_function=bigcode_config.activation_function,
+        attn_pdrop=bigcode_config.attn_pdrop,
+        bos_token_id=bigcode_config.bos_token_id,
+        embd_pdrop=bigcode_config.embd_pdrop,
+        eos_token_id=bigcode_config.eos_token_id,
+        initializer_range=bigcode_config.initializer_range,
+        layer_norm_epsilon=bigcode_config.layer_norm_epsilon,
+        max_batch_size=bigcode_config.max_batch_size,
+        max_sequence_length=bigcode_config.max_sequence_length,
+        model_type=bigcode_config.model_type,
+        multi_query=bigcode_config.multi_query,
+        n_embd=bigcode_config.n_embd,
+        n_head=bigcode_config.n_head,
+        n_inner=bigcode_config.n_inner,
+        n_layer=bigcode_config.n_layer,
+        n_positions=bigcode_config.n_positions,
+        resid_pdrop=bigcode_config.resid_pdrop,
+        scale_attn_weights=bigcode_config.scale_attn_weights,
+        summary_activation=bigcode_config.summary_activation,
+        summary_first_dropout=bigcode_config.summary_first_dropout,
+        summary_proj_to_labels=bigcode_config.summary_proj_to_labels,
+        summary_type=bigcode_config.summary_type,
+        summary_use_proj=bigcode_config.summary_use_proj,
+        use_cache=bigcode_config.use_cache,
+        vocab_size=bigcode_config.vocab_size,
+    )

flash_attn/models/gpt.py

@@ -13,6 +13,7 @@ import torch.nn.functional as F
 from einops import rearrange
 from transformers import GPT2Config
 
+from flash_attn.models.bigcode import remap_state_dict_hf_bigcode
 from flash_attn.models.falcon import remap_state_dict_hf_falcon
 from flash_attn.models.gpt_neox import remap_state_dict_hf_gpt_neox
 from flash_attn.models.gptj import remap_state_dict_hf_gptj
@@ -21,12 +22,16 @@ from flash_attn.models.opt import remap_state_dict_hf_opt
 from flash_attn.modules.block import Block, ParallelBlock
 from flash_attn.modules.embedding import GPT2Embeddings, ParallelGPT2Embeddings
 from flash_attn.modules.mha import MHA, ParallelMHA
-from flash_attn.modules.mlp import (FusedMLP, GatedMlp, Mlp, ParallelFusedMLP,
-                                    ParallelGatedMlp, ParallelMLP)
+from flash_attn.modules.mlp import (
+    FusedMLP,
+    GatedMlp,
+    Mlp,
+    ParallelFusedMLP,
+    ParallelGatedMlp,
+    ParallelMLP,
+)
 from flash_attn.ops.activations import sqrelu_fwd
-from flash_attn.utils.distributed import (all_gather_raw,
-                                          get_dim_for_local_rank,
-                                          sync_shared_params)
+from flash_attn.utils.distributed import all_gather_raw, get_dim_for_local_rank, sync_shared_params
 from flash_attn.utils.generation import GenerationMixin
 from flash_attn.utils.pretrained import state_dict_from_pretrained
 
@@ -41,8 +46,7 @@ except ImportError:
     dropout_add_layer_norm = None
 
 try:
-    from flash_attn.ops.layer_norm import \
-        dropout_add_layer_norm_parallel_residual
+    from flash_attn.ops.layer_norm import dropout_add_layer_norm_parallel_residual
 except ImportError:
     dropout_add_layer_norm_parallel_residual = None
 
@@ -129,6 +133,7 @@ def create_mlp_cls(config, layer_idx=None, process_group=None, device=None, dtyp
             "gelu_new",
             "gelu_fast",
             "gelu_approx",
+            "gelu_pytorch_tanh",
             "relu",
             "sqrelu",
         ]
@@ -144,6 +149,7 @@ def create_mlp_cls(config, layer_idx=None, process_group=None, device=None, dtyp
             "gelu_new",
             "gelu_fast",
             "gelu_approx",
+            "gelu_pytorch_tanh",
             "relu",
             "sqrelu",
             "glu",
@@ -182,7 +188,8 @@ def create_mlp_cls(config, layer_idx=None, process_group=None, device=None, dtyp
             else:
                 approximate = (
                     "tanh"
-                    if config.activation_function in ["gelu_new", "gelu_fast", "gelu_approx"]
+                    if config.activation_function
+                    in ["gelu_new", "gelu_fast", "gelu_approx", "gelu_pytorch_tanh"]
                     else "none"
                 )
                 activation = partial(F.gelu, approximate=approximate)
@@ -215,7 +222,8 @@ def create_mlp_cls(config, layer_idx=None, process_group=None, device=None, dtyp
                 raise ImportError("fused_dense is not installed")
             activation = (
                 "gelu_approx"
-                if config.activation_function in ["gelu_new", "gelu_fast", "gelu_approx"]
+                if config.activation_function
+                in ["gelu_new", "gelu_fast", "gelu_approx", "gelu_pytorch_tanh"]
                 else config.activation_function
             )
             mlp_cls = FusedMLP if process_group is None else ParallelFusedMLP
@@ -352,6 +360,8 @@ class GPTPreTrainedModel(nn.Module):
             state_dict = remap_state_dict_hf_falcon(state_dict, config)
         elif model_name.startswith("meta-llama/Llama-"):
             state_dict = remap_state_dict_hf_llama(state_dict, config)
+        elif model_name.startswith("bigcode/") or model_name.startswith("WizardLM/"):
+            state_dict = remap_state_dict_hf_bigcode(state_dict, config)
         else:
             raise NotImplementedError(f"Model {model_name} not supported")
         if world_size > 1:
@@ -394,6 +404,7 @@ class GPTModel(GPTPreTrainedModel):
             "gelu_new",
             "gelu_fast",
             "gelu_approx",
+            "gelu_pytorch_tanh",
             "relu",
             "sqrelu",
             "glu",
@@ -628,7 +639,9 @@ class GPTLMHeadModel(GPTPreTrainedModel, GenerationMixin):
         https://github.com/NVIDIA/apex/blob/3ff1a10f72ec07067c4e44759442329804ac5162/apex/transformer/testing/standalone_transformer_lm.py#L470
         num_last_tokens: if > 0, only return the logits for the last n tokens
         """
-        assert input_ids.ndim == 2, f"Expected `input_ids` to have shape [b, slen], but got shape {input_ids.shape}"
+        assert (
+            input_ids.ndim == 2
+        ), f"Expected `input_ids` to have shape [b, slen], but got shape {input_ids.shape}"
         b, slen = input_ids.shape
         hidden_states = self.transformer(
             input_ids, position_ids=position_ids, inference_params=inference_params
@@ -845,11 +858,11 @@ def combine_state_dicts_tp(state_dicts: list[dict[str, torch.Tensor]], config: G
                         nheadqkv=rank_n_head + 2 * rank_n_head_kv,
                         headdim=headdim,
                     )
-                    for s, rank_n_head, rank_n_head_kv in zip(state_dicts, n_head_each_rank, n_head_kv_each_rank)
+                    for s, rank_n_head, rank_n_head_kv in zip(
+                        state_dicts, n_head_each_rank, n_head_kv_each_rank
+                    )
                 ]
-                wq = torch.cat(
-                    [x[: n_head_each_rank[rank]] for rank, x in enumerate(xs)], dim=0
-                )
+                wq = torch.cat([x[: n_head_each_rank[rank]] for rank, x in enumerate(xs)], dim=0)
                 wk = torch.cat(
                     [
                         x[

tests/models/test_bert.py

@@ -6,12 +6,15 @@ import torch
 import torch.nn.functional as F
 from einops import rearrange
 from transformers import BertConfig
-from transformers.models.bert.modeling_bert import \
-    BertForPreTraining as BertForPreTrainingHF
+from transformers.models.bert.modeling_bert import BertForPreTraining as BertForPreTrainingHF
 from transformers.models.bert.modeling_bert import BertModel as BertModelHF
 
-from flash_attn.models.bert import (BertForPreTraining, BertModel,
-                                    inv_remap_state_dict, remap_state_dict)
+from flash_attn.models.bert import (
+    BertForPreTraining,
+    BertModel,
+    inv_remap_state_dict,
+    remap_state_dict,
+)
 from flash_attn.utils.pretrained import state_dict_from_pretrained
 
 
@@ -102,7 +105,7 @@ def test_bert_optimized(model_name):
     dtype = torch.float16
     config = BertConfig.from_pretrained(model_name)
     # Our implementation of fused_mlp assumes the activation is
-    # nn.GELU(approximate='tanh'). Huggingface calls it "gelu_new" or "gelu_fast".
+    # nn.GELU(approximate='tanh'). Huggingface calls it "gelu_new", "gelu_fast", or "gelu_pytorch_tanh".
     # If you just want "gelu", disable fused_mlp.
     config.hidden_act = "gelu_new"
     config.use_flash_attn = True
@@ -209,7 +212,7 @@ def test_bert_dense_seq_output(model_name, has_key_padding_mask, last_layer_subs
     dtype = torch.float16
     config = BertConfig.from_pretrained(model_name)
     # Our implementation of fused_mlp assumes the activation is
-    # nn.GELU(approximate='tanh'). Huggingface calls it "gelu_new" or "gelu_fast".
+    # nn.GELU(approximate='tanh'). Huggingface calls it "gelu_new", "gelu_fast", or "gelu_pytorch_tanh".
     # If you just want "gelu", disable fused_mlp.
     config.hidden_act = "gelu_new"
     config.use_flash_attn = True

tests/models/test_bigcode.py

+import time
+
+import pytest
+import torch
+from transformers import AutoTokenizer, GPTBigCodeConfig
+from transformers.models.gpt_bigcode.modeling_gpt_bigcode import GPTBigCodeForCausalLM
+
+from flash_attn.models.bigcode import bigcode_config_to_gpt2_config, inv_remap_state_dict_hf_bigcode
+from flash_attn.models.gpt import GPTLMHeadModel, remap_state_dict_hf_bigcode
+from flash_attn.utils.generation import update_graph_cache
+from flash_attn.utils.pretrained import state_dict_from_pretrained
+
+
+@pytest.mark.parametrize("model_name", ["bigcode/starcoderbase-1b", "WizardLM/WizardCoder-1B-V1.0"])
+def test_bigcode_state_dict(model_name):
+    config = bigcode_config_to_gpt2_config(GPTBigCodeConfig.from_pretrained(model_name))
+    pretrained_state_dict = remap_state_dict_hf_bigcode(
+        state_dict_from_pretrained(model_name), config
+    )
+    model = GPTLMHeadModel(config, device="meta")
+    state_dict = model.state_dict()
+    assert state_dict.keys() == pretrained_state_dict.keys()
+    for k in state_dict.keys():
+        assert state_dict[k].shape == pretrained_state_dict[k].shape
+
+
+@pytest.mark.parametrize("model_name", ["bigcode/starcoderbase-1b", "WizardLM/WizardCoder-1B-V1.0"])
+def test_bigcode_optimized(model_name):
+    """Check that our implementation of BigCode (with all optimizations enabled) matches the
+    HF implementation: the output of our forward pass in fp16 should be around the same as the HF
+    forward pass in fp16, when compared to the HF forward pass in fp32.
+    """
+    dtype = torch.float16
+    device = "cuda"
+    config = bigcode_config_to_gpt2_config(GPTBigCodeConfig.from_pretrained(model_name))
+    config.use_flash_attn = True  # FlashAttention-2 supports headdim 256
+    config.fused_bias_fc = True
+    config.fused_mlp = True
+    config.fused_dropout_add_ln = True
+    config.residual_in_fp32 = True
+
+    model = GPTLMHeadModel.from_pretrained(model_name, config, device=device, dtype=dtype)
+    model.eval()
+
+    torch.manual_seed(0)
+    batch_size = 2
+    max_seqlen = 256
+    input_ids = torch.randint(
+        0, config.vocab_size, (batch_size, max_seqlen), dtype=torch.long, device=device
+    )
+    with torch.no_grad():
+        out = model.transformer(input_ids)
+        logits = model(input_ids).logits
+    del model
+
+    # Without device_map, the model is loaded on the CPU, which is very slow
+    model_ref = GPTBigCodeForCausalLM.from_pretrained(model_name, device_map={"": device})
+    model_ref.eval()
+    with torch.no_grad():
+        out_ref = model_ref.transformer(input_ids).last_hidden_state
+        logits_ref = model_ref(input_ids).logits
+    del model_ref
+
+    model_hf = GPTBigCodeForCausalLM.from_pretrained(
+        model_name, torch_dtype=dtype, device_map={"": device}
+    )
+    model_hf.eval()
+    out_hf = model_hf.transformer(input_ids).last_hidden_state
+    logits_hf = model_hf(input_ids).logits
+    del model_hf
+
+    print(f"Output max diff: {(out - out_ref).abs().max().item()}")
+    print(f"Output mean diff: {(out - out_ref).abs().mean().item()}")
+    print(f"HF fp16 max diff: {(out_hf - out_ref).abs().max().item()}")
+    print(f"HF fp16 mean diff: {(out_hf - out_ref).abs().mean().item()}")
+    assert (out - out_ref).abs().max().item() < 3 * (out_hf - out_ref).abs().max().item()
+
+    print(f"Logits max diff: {(logits - logits_ref).abs().max().item()}")
+    print(f"Logits mean diff: {(logits - logits_ref).abs().mean().item()}")
+    print(f"HF fp16 max diff: {(logits_hf - logits_ref).abs().max().item()}")
+    print(f"HF fp16 mean diff: {(logits_hf - logits_ref).abs().mean().item()}")
+    assert (logits - logits_ref).abs().max().item() < 3 * (
+        logits_hf - logits_ref
+    ).abs().max().item()
+
+
+@pytest.mark.parametrize("model_name", ["bigcode/starcoderbase-1b", "WizardLM/WizardCoder-1B-V1.0"])
+def test_bigcode_generation(model_name):
+    """Check that our implementation of BigCode (with all optimizations enabled) matches the
+    HF implementation: the output of our forward pass in fp16 should be around the same as the HF
+    forward pass in fp16, when compared to the HF forward pass in fp32.
+    """
+    dtype = torch.float16
+    device = "cuda"
+    config = bigcode_config_to_gpt2_config(GPTBigCodeConfig.from_pretrained(model_name))
+    config.use_flash_attn = True  # FlashAttention-2 supports headdim 256
+    config.fused_bias_fc = True
+    config.fused_mlp = True
+    config.fused_dropout_add_ln = True
+    # Only prenorm supports residual_in_fp32
+    config.residual_in_fp32 = True
+
+    tokenizer = AutoTokenizer.from_pretrained(model_name)
+    eos_token_id = tokenizer.eos_token_id
+
+    torch.manual_seed(0)
+    batch_size = 1
+    seqlen = 100
+    max_length = 150
+    input_ids = torch.randint(
+        0, config.vocab_size, (batch_size, seqlen), dtype=torch.long, device=device
+    )
+
+    model_hf = GPTBigCodeForCausalLM.from_pretrained(
+        model_name, torch_dtype=dtype, device_map={"": device}
+    )
+    model_hf.eval()
+    print("HF fp16")
+    torch.cuda.synchronize()
+    start = time.time()
+    out_hf = model_hf.generate(
+        input_ids=input_ids, max_length=max_length, return_dict_in_generate=True, output_scores=True
+    )
+    torch.cuda.synchronize()
+    print(f"Prompt processing + decoding time: {(time.time() - start) * 1000:.0f}ms")
+    del model_hf
+
+    model_ref = GPTBigCodeForCausalLM.from_pretrained(model_name, device_map={"": device})
+    model_ref.eval()
+    with torch.no_grad():
+        logits_ref = model_ref(out_hf.sequences).logits[:, (seqlen - 1) : -1]
+    del model_ref
+
+    model = GPTLMHeadModel.from_pretrained(model_name, config, device=device, dtype=dtype)
+    model.eval()
+
+    print("Without CUDA graph")
+    torch.cuda.synchronize()
+    start = time.time()
+    out = model.generate(
+        input_ids=input_ids,
+        max_length=max_length,
+        eos_token_id=eos_token_id,
+        fused_ft_kernel=True,
+        return_dict_in_generate=True,
+        output_scores=True,
+        enable_timing=True,
+        teacher_outputs=out_hf.sequences,
+    )
+    torch.cuda.synchronize()
+    print(f"Prompt processing + decoding time: {(time.time() - start) * 1000:.0f}ms")
+
+    # Capture graph outside the timing loop
+    batch_size, seqlen_og = input_ids.shape
+    model._decoding_cache = update_graph_cache(model, None, batch_size, seqlen_og, max_length)
+    print("With CUDA graph")
+    torch.cuda.synchronize()
+    start = time.time()
+    out_cg = model.generate(
+        input_ids=input_ids,
+        max_length=max_length,
+        fused_ft_kernel=True,
+        cg=True,
+        return_dict_in_generate=True,
+        output_scores=True,
+        enable_timing=True,
+        teacher_outputs=out_hf.sequences,
+    )
+    torch.cuda.synchronize()
+    print(f"Prompt processing + decoding time: {(time.time() - start) * 1000:.0f}ms")
+
+    with torch.no_grad():
+        logits_parallel = model(out_hf.sequences).logits[:, (seqlen - 1) : -1]
+    logits_hf = torch.stack(out_hf.scores, dim=1)
+    logits = torch.stack(out.scores, dim=1)
+    logits_cg = torch.stack(out_cg.scores, dim=1)
+
+    del model
+
+    hf_error = (logits_hf - logits_ref).abs().max().item()
+    assert (logits_parallel - logits_ref).abs().max().item() < 2 * hf_error
+
+    print(f"HF fp16 logits max diff: {hf_error}")
+    print(f"Logits max diff: {(logits - logits_ref).abs().max().item() }")
+    assert (logits - logits_ref).abs().max().item() < 2 * hf_error
+    print(f"Logits CG max diff: {(logits_cg - logits_ref).abs().max().item() }")
+    assert (logits_cg - logits_ref).abs().max().item() < 2 * hf_error
+
+
+@pytest.mark.parametrize("model_name", ["bigcode/starcoderbase-1b", "WizardLM/WizardCoder-1B-V1.0"])
+def test_inv_remap_state_dict(model_name: str):
+    """
+    Verify that we can convert a HF BigCode model to flash_attn and back.
+    """
+
+    state_dict = state_dict_from_pretrained(model_name)
+    config = GPTBigCodeConfig.from_pretrained(model_name)
+
+    flash_state_dict = remap_state_dict_hf_bigcode(state_dict, config)
+    recovered_state_dict = inv_remap_state_dict_hf_bigcode(flash_state_dict, config)
+
+    assert set(state_dict.keys()) == set(recovered_state_dict.keys())
+
+    for k in state_dict.keys():
+        assert state_dict[k].shape == recovered_state_dict[k].shape
+        torch.testing.assert_close(state_dict[k], recovered_state_dict[k], rtol=1e-6, atol=1e-6)