[inference] Adapted to Rotary Embedding and RMS Norm (#5283)

* adapted to rotary_embedding

* adapted to nopad rms norm

* fix bugs in benchmark

* fix flash_decoding.py

colossalai/inference/modeling/models/llama.py

@@ -6,7 +6,12 @@ from transformers.models.llama.modeling_llama import LlamaAttention, LlamaDecode
 
 from colossalai.inference.modeling.layers.attention import PagedAttention
 from colossalai.inference.struct import BatchInfo
-from colossalai.kernel.triton import context_attention_unpadded, copy_kv_to_blocked_cache, flash_decoding_attention
+from colossalai.kernel.triton import (
+    context_attention_unpadded,
+    copy_kv_to_blocked_cache,
+    flash_decoding_attention,
+    rotary_embedding,
+)
 from colossalai.logging import get_dist_logger
 
 from flash_attn.bert_padding import index_first_axis, pad_input  # noqa
@@ -72,9 +77,10 @@ def llama_model_forward(
     attention_mask = batch.get_attn_mask(padding_id)
 
     if attention_mask is not None:
-        # TODO After the nopad version is implemented, we will use the following code to get sequence_lengths.
-        # sequence_lengths = batch.get_sequence_lengths()
-        sequence_lengths = attention_mask.sum(dim=-1, dtype=torch.int32)
+        if HAS_TRITON:
+            sequence_lengths = attention_mask.sum(dim=-1, dtype=torch.int32)
+        else:
+            sequence_lengths = batch.get_sequence_lengths()
     else:
         sequence_lengths = batch.get_sequence_lengths()
 
@@ -96,6 +102,8 @@ def llama_model_forward(
 
     hidden_states = self.embed_tokens(input_ids)
 
+    cos_sin = get_cos_sin(sequence_lengths, self._cos_cached, self._sin_cached, batch.is_prompts, hidden_states.dtype)
+
     for layer_id, decoder_layer in enumerate(self.layers):
         hidden_states = decoder_layer(
             hidden_states,
@@ -107,6 +115,7 @@ def llama_model_forward(
             sequence_lengths=sequence_lengths,
             attention_mask=attention_mask,
             kv_seq_len=kv_seq_len,
+            cos_sin=cos_sin,
         )
 
     hidden_states = self.norm(hidden_states)
@@ -125,6 +134,7 @@ def llama_decoder_layer_forward(
     sequence_lengths: int = None,
     attention_mask: torch.Tensor = None,
     kv_seq_len: int = 0,
+    cos_sin: Tuple[torch.Tensor] = None,
 ) -> Tuple[torch.FloatTensor, Optional[Tuple[torch.FloatTensor, torch.FloatTensor]]]:
     residual = hidden_states
 
@@ -140,6 +150,7 @@ def llama_decoder_layer_forward(
         sequence_lengths=sequence_lengths,
         attention_mask=attention_mask,
         kv_seq_len=kv_seq_len,
+        cos_sin=cos_sin,
     )
 
     hidden_states = residual + hidden_states
@@ -166,27 +177,16 @@ def llama_attn_forward(
     sequence_lengths: torch.Tensor = None,
     attention_mask: torch.Tensor = None,
     kv_seq_len: int = 0,
+    cos_sin: Tuple[torch.Tensor] = None,
 ) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]:
     bsz, q_len, _ = hidden_states.size()
 
-    query_states = self.q_proj(hidden_states).view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)
-    key_states = self.k_proj(hidden_states).view(bsz, q_len, self.num_key_value_heads, self.head_dim).transpose(1, 2)
-    value_states = self.v_proj(hidden_states).view(bsz, q_len, self.num_key_value_heads, self.head_dim).transpose(1, 2)
-
-    kv_seq_len = max(sequence_lengths).item()
-
-    cos, sin = self.rotary_emb(value_states, seq_len=kv_seq_len)
+    query_states = self.q_proj(hidden_states).view(bsz, q_len, self.num_heads, self.head_dim)
+    key_states = self.k_proj(hidden_states).view(bsz, q_len, self.num_key_value_heads, self.head_dim)
+    value_states = self.v_proj(hidden_states).view(bsz, q_len, self.num_key_value_heads, self.head_dim)
 
-    query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin, position_ids)
-
-    query_states = query_states.transpose(1, 2)
-    key_states = key_states.transpose(1, 2)
-    value_states = value_states.transpose(1, 2)
-
-    _, _, _, block_size = k_cache.shape
-
-    if is_prompts:
-        if HAS_TRITON:
+    if HAS_TRITON:
+        if is_prompts:
             if attention_mask is not None:
                 query_states, key_states, value_states, indices = unpading_input(
                     query_states, key_states, value_states, attention_mask
@@ -195,29 +195,44 @@ def llama_attn_forward(
                 query_states = query_states.view(-1, self.num_heads, self.head_dim)
                 key_states = key_states.view(-1, self.num_heads, self.head_dim)
                 value_states = value_states.view(-1, self.num_heads, self.head_dim)
+        else:
+            query_states = query_states.squeeze(dim=1)
+            key_states = key_states.squeeze(dim=1)
+            value_states = value_states.squeeze(dim=1)
+
+        rotary_embedding(query_states, key_states, cos_sin[0], cos_sin[1])
 
+        _, _, _, block_size = k_cache.shape
+
+        if is_prompts:
             attn_output = context_attention_unpadded(
                 query_states, key_states, value_states, k_cache, v_cache, sequence_lengths, block_tables, block_size
             )
             if attention_mask is not None:
                 attn_output = pad_input(attn_output, indices, bsz, q_len)
         else:
-            attn_output = PagedAttention.pad_context_forward(
-                query_states, key_states, value_states, k_cache, v_cache, sequence_lengths, block_tables, attention_mask
-            )
-    else:
-        if HAS_TRITON:
             copy_kv_to_blocked_cache(key_states, k_cache, kv_lengths=sequence_lengths, block_tables=block_tables)
             copy_kv_to_blocked_cache(value_states, v_cache, kv_lengths=sequence_lengths, block_tables=block_tables)
-            # TODO Add dummy transpose and squeeze on in/out tensors of the triton flash decoding kernel
-            # in order to maintain compatibility. This part as well as the logics of handling query_states and attn_output
-            # should be revised, as we could see in previous part of `llama_attn_forward` we still have
-            # redundant transpose and the in/out of torch- and triton-version decoding kernel are not consistent.
-            query_states = query_states.transpose(1, 2)
             attn_output = flash_decoding_attention(
                 query_states, k_cache, v_cache, sequence_lengths, block_tables, block_size
             )
             attn_output = attn_output.squeeze(1)
+    else:
+        query_states = query_states.transpose(1, 2)
+        key_states = key_states.transpose(1, 2)
+        value_states = value_states.transpose(1, 2)
+
+        cos, sin = self.rotary_emb(value_states, seq_len=kv_seq_len)
+        query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin, position_ids)
+
+        query_states = query_states.transpose(1, 2)
+        key_states = key_states.transpose(1, 2)
+        value_states = value_states.transpose(1, 2)
+
+        if is_prompts:
+            attn_output = PagedAttention.pad_context_forward(
+                query_states, key_states, value_states, k_cache, v_cache, sequence_lengths, block_tables, attention_mask
+            )
         else:
             attn_output = PagedAttention.pad_decoding_forward(
                 query_states, key_states, value_states, k_cache, v_cache, sequence_lengths, block_tables, attention_mask
@@ -232,6 +247,15 @@ def llama_attn_forward(
 
 @torch.no_grad()
 def generate_padding_position_id(attention_mask: torch.Tensor) -> torch.Tensor:
+    """Generate padding position_id through attention mask.
+
+    Args:
+        attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`):
+            Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`:
+
+    Returns:
+        torch.Tensor: The padding position_id.
+    """
     position_ids = attention_mask.long().cumsum(-1) - 1
     position_ids.masked_fill_(attention_mask == 0, 1)
     return position_ids
@@ -239,9 +263,34 @@ def generate_padding_position_id(attention_mask: torch.Tensor) -> torch.Tensor:
 
 @torch.no_grad()
 def unpading_input(q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, attention_mask: torch.Tensor):
+    """Convert padding input to nopad input.
+
+    Args:
+        q (torch.Tensor): [batch_size, q_seq_len, head_num, head_dim]
+        k (torch.Tensor): [batch_size, q_seq_len, head_num, head_dim]
+        v (torch.Tensor): [batch_size, q_seq_len, head_num, head_dim]
+        attention_mask (torch.Tensor): [batch_size, sequence_length]
+
+    Returns:
+        Tuple[torch.Tensor]: The unpad q, k, v and The index of valid data in each batch.
+
+    """
     indices = torch.nonzero(attention_mask.flatten(), as_tuple=False).flatten()
     batch_size, kv_seq_len, num_key_value_heads, head_dim = q.shape
     q = index_first_axis(q.reshape(batch_size * kv_seq_len, num_key_value_heads, head_dim), indices)
     k = index_first_axis(k.reshape(batch_size * kv_seq_len, num_key_value_heads, head_dim), indices)
     v = index_first_axis(v.reshape(batch_size * kv_seq_len, num_key_value_heads, head_dim), indices)
     return (q, k, v, indices)
+
+
+@torch.no_grad()
+def get_cos_sin(lengths, cos_cache, sin_cache, is_prompts, dtype):
+    if is_prompts:
+        index_arrays = [torch.arange(length) for length in lengths]
+    else:
+        index_arrays = [(length - 1).view(-1) for length in lengths]
+    indices = torch.cat(index_arrays, dim=-1)
+    cos_output = cos_cache[indices].to(dtype=dtype)
+    sin_output = sin_cache[indices].to(dtype=dtype)
+
+    return (cos_output, sin_output)

colossalai/inference/modeling/policy/llama.py

@@ -1,11 +1,13 @@
 from functools import partial
 
+import torch
 from transformers.models.llama.modeling_llama import (
     LlamaAttention,
     LlamaDecoderLayer,
     LlamaFlashAttention2,
     LlamaForCausalLM,
     LlamaModel,
+    LlamaRMSNorm,
     LlamaSdpaAttention,
 )
 
@@ -15,11 +17,31 @@ from colossalai.inference.modeling.models.llama import (
     llama_decoder_layer_forward,
     llama_model_forward,
 )
+from colossalai.inference.utils import init_to_get_rotary
 from colossalai.shardformer.policies.base_policy import ModulePolicyDescription, SubModuleReplacementDescription
 
 # import colossalai
 from colossalai.shardformer.policies.llama import LlamaForCausalLMPolicy
 
+try:
+    from colossalai.kernel.triton import rms_layernorm
+
+    HAS_TRITON_RMSNORM = True
+except:
+    print("you should install triton from https://github.com/openai/triton")
+    HAS_TRITON_RMSNORM = False
+
+
+def get_triton_rmsnorm_forward():
+    if HAS_TRITON_RMSNORM:
+
+        def _triton_rmsnorm_forward(self: LlamaRMSNorm, hidden_states: torch.Tensor):
+            return rms_layernorm(hidden_states, self.weight.data, self.variance_epsilon)
+
+        return _triton_rmsnorm_forward
+    else:
+        return None
+
 
 class LlamaModelInferPolicy(LlamaForCausalLMPolicy):
     def __init__(self) -> None:
@@ -162,4 +184,18 @@ class LlamaModelInferPolicy(LlamaForCausalLMPolicy):
             description=method_replacement, policy=policy, target_key=LlamaSdpaAttention
         )
 
+        infer_forward = None
+        if HAS_TRITON_RMSNORM:
+            infer_forward = get_triton_rmsnorm_forward()
+
+        if infer_forward is not None:
+            method_replacement = {"forward": partial(infer_forward)}
+            self.append_or_create_method_replacement(
+                description=method_replacement, policy=policy, target_key=LlamaRMSNorm
+            )
+
         return policy
+
+    def postprocess(self):
+        init_to_get_rotary(self.model.model)
+        return self.model

colossalai/kernel/triton/flash_decoding.py

@@ -18,7 +18,6 @@ def _flash_decoding_fwd_kernel(
     kv_seq_len,  # [batch_size]
     stride_qt,
     stride_qh,
-    stride_ql,
     stride_qd,
     stride_cacheb,
     stride_cacheh,
@@ -199,7 +198,7 @@ def flash_decoding_attention(
     Flash decoding implemented with a blocked KV Cache (PagedAttention) during decoding stage.
 
     Args:
-        q (torch.Tensor):       [bsz, num_heads, q_len(1), head_dim]
+        q (torch.Tensor):       [bsz, num_heads, head_dim]
         k_cache (torch.Tensor): [num_blocks, num_kv_heads, head_dim, block_size]
         v_cache (torch.Tensor): [num_blocks, num_kv_heads, head_dim, block_size]
         kv_seq_len (torch.Tensor): [batch_size]
@@ -216,7 +215,10 @@ def flash_decoding_attention(
     Returns:
         Output tensor with shape [bsz, num_heads, q_len, head_dim]
     """
-    bsz, num_heads, _, head_dim = q.shape
+    if q.dim() == 3:
+        bsz, num_heads, head_dim = q.shape
+    else:
+        raise ValueError(f"The query dim should be 3, but got {q.dim()}.")
 
     assert head_dim in {32, 64, 128, 256}
     assert kv_seq_len.shape[0] == block_tables.shape[0] == bsz, (
@@ -262,7 +264,6 @@ def flash_decoding_attention(
         q.stride(0),
         q.stride(1),
         q.stride(2),
-        q.stride(3),
         k_cache.stride(0),
         k_cache.stride(1),
         k_cache.stride(2),

colossalai/kernel/triton/kvcache_copy.py

@@ -53,16 +53,23 @@ def copy_kv_to_blocked_cache(
     Copy keys or values to the blocked key/value cache during decoding stage.
 
     Parameters:
-    - k (torch.Tensor): [bsz, 1, num_kv_heads, head_dim] - Keys or values during decoding with seq len 1.
+    - k (torch.Tensor): [bsz, 1, num_kv_heads, head_dim]/[bsz, num_kv_heads, head_dim] - Keys or values during decoding with seq len 1.
     - k_cache (torch.Tensor): [num_blocks, num_kv_heads, head_dim, block_size] - Blocked key or value cache.
     - kv_lengths (torch.Tensor): [bsz] - Past key/value sequence lengths plus current sequence length for each sequence.
     - block_tables (torch.Tensor): [bsz, max_blocks_per_sequence] - Block tables for each sequence.
     """
-    assert k.dim() == 4, "Unsupported shape of k (supposed to be used for decoding stage)"
-    assert k.size(1) == 1, "Unsupported kv seq len (supposed to be used for decoding stage)"
     assert k.size(-1) == k_cache.size(-2), "Incompatible head dim"
     assert k.dtype == k_cache.dtype, "Expected consistent dtype for tensor and cache."
-    bsz, _, num_kv_heads, head_dim = k.shape
+    if k.dim() == 4:
+        assert k.size(1) == 1, "Unsupported kv seq len (supposed to be used for decoding stage)"
+        bsz, _, num_kv_heads, head_dim = k.shape
+        # [bsz, 1, num_kv_heads, head_dim] -> [bsz, num_kv_heads, head_dim]
+        k = k.squeeze(dim=1)
+    elif k.dim() == 3:
+        bsz, num_kv_heads, head_dim = k.shape
+    else:
+        raise ValueError(f"The key dim should be 3 or 4, but got {k.dim()}.")
+
     assert kv_lengths.shape[0] == block_tables.shape[0] == bsz, (
         f"Got incompatible batch size (number of seqs):\n"
         f"  Past kv sequence lengths bsz {kv_lengths.shape[0]}; "
@@ -71,8 +78,6 @@ def copy_kv_to_blocked_cache(
 
     # Modify if the shape of kv cahce is changed.
     block_size = k_cache.size(-1)
-    # [bsz, 1, num_kv_heads, head_dim] -> [bsz, num_kv_heads, head_dim]
-    k = k.squeeze(dim=1)
 
     num_warps = 8 if head_dim > 128 else 4
 

examples/inference/benchmark_llama.py

@@ -95,10 +95,13 @@ def benchmark_inference(args):
 
         if args.dtype == "fp16":
             model = model.half()
-        elif args.dtype == "fp16":
+        elif args.dtype == "bf16":
             model = model.to(torch.bfloat16)
 
-        mbsz = args.mbsz
+        if args.continous_batching:
+            mbsz = args.mbsz
+        else:
+            mbsz = args.batch_size
         if args.mode == "caiinference":
             inference_config = InferenceConfig(
                 dtype=args.dtype,
@@ -205,5 +208,8 @@ if __name__ == "__main__":
         choices=["caiinference", "transformers"],
         help="decide which inference framework to run",
     )
+    parser.add_argument(
+        "-cb", "--continous_batching", default=False, action="store_true", help="enable continous batching"
+    )
     args = parser.parse_args()
     benchmark(args)