[WIP] Add HPU support to vLLM v1

vllm/attention/selector.py

@@ -24,6 +24,7 @@
     OPENVINO = enum.auto()
     FLASHINFER = enum.auto()
     HPU_ATTN = enum.auto()
+    HPU_ATTN_V1 = enum.auto()
     PALLAS = enum.auto()
     IPEX = enum.auto()
     NO_ATTENTION = enum.auto()
@@ -172,6 +173,10 @@
         return FlashInferBackend
     elif backend == _Backend.HPU_ATTN:
         logger.info("Using HPUAttention backend.")
+        from vllm.v1.attention.backends.hpu_attn import HPUAttentionBackendV1
+        return HPUAttentionBackendV1
+    elif backend == _Backend.HPU_ATTN_V1:
+        logger.info("Using HPUAttentionV1 backend.")
         from vllm.attention.backends.hpu_attn import HPUAttentionBackend
         return HPUAttentionBackend
     elif backend == _Backend.PALLAS:
@@ -249,6 +254,10 @@
         return _Backend.ROCM_FLASH
 
     if current_platform.is_hpu():
+        if selected_backend != _Backend.HPU_ATTN and selected_backend != _Backend.HPU_ATTN_V1:
+            logger.info("Cannot use %s backend on HPU.", selected_backend)
+        if use_v1:
+            return _Backend.HPU_ATTN_V1
         return _Backend.HPU_ATTN
 
     if use_v1:

vllm/v1/attention/backends/hpu_attn.py

@@ -0,0 +1,289 @@
+###############################################################################
+# Copyright (C) 2024 Habana Labs, Ltd. an Intel Company
+###############################################################################
+
+import os
+from dataclasses import dataclass
+from typing import Any, Dict, List, Optional, Tuple, Type
+
+import torch
+import vllm_hpu_extension.ops as ops
+from vllm_hpu_extension.utils import Matmul, Softmax, VLLMKVCache
+
+from vllm.attention.backends.abstract import (AttentionBackend, AttentionImpl,
+                                              AttentionMetadata, AttentionType)
+from vllm.attention.backends.utils import CommonAttentionState
+from vllm.attention.ops.hpu_paged_attn import (HPUPagedAttention,
+                                               HPUPagedAttentionMetadata)
+from vllm.logger import init_logger
+from vllm.utils import is_fake_hpu
+
+logger = init_logger(__name__)
+
+
+class HPUAttentionBackend(AttentionBackend):
+
+    @staticmethod
+    def get_name() -> str:
+        return "hpu-attn"
+
+    @staticmethod
+    def get_impl_cls() -> Type["HPUAttentionImpl"]:
+        return HPUAttentionImpl
+
+    @staticmethod
+    def get_metadata_cls() -> Type["AttentionMetadata"]:
+        return HPUAttentionMetadata
+
+    @staticmethod
+    def get_state_cls() -> Type["CommonAttentionState"]:
+        return CommonAttentionState
+
+    @staticmethod
+    def get_kv_cache_shape(
+        num_blocks: int,
+        block_size: int,
+        num_kv_heads: int,
+        head_size: int,
+    ) -> Tuple[int, ...]:
+        return HPUPagedAttention.get_kv_cache_shape(num_blocks, block_size,
+                                                    num_kv_heads, head_size)
+
+    @staticmethod
+    def swap_blocks(
+        src_kv_cache: torch.Tensor,
+        dst_kv_cache: torch.Tensor,
+        src_to_dsts: torch.Tensor,
+    ) -> None:
+        HPUPagedAttention.swap_blocks(src_kv_cache, dst_kv_cache, src_to_dsts)
+
+    @staticmethod
+    def copy_blocks(
+        kv_caches: List[torch.Tensor],
+        src_to_dsts: torch.Tensor,
+    ) -> None:
+        HPUPagedAttention.copy_blocks(kv_caches, src_to_dsts)
+
+
+@dataclass
+class HPUAttentionMetadata(HPUPagedAttentionMetadata, AttentionMetadata):
+    """Metadata for HPUAttentionbackend."""
+    # Currently, input sequences can only contain all prompts
+    # or all decoding. True if all sequences are prompts.
+    is_prompt: bool
+    attn_bias: Optional[torch.Tensor]
+    seq_lens_tensor: Optional[torch.Tensor]
+    context_lens_tensor: Optional[torch.Tensor]
+
+
+class HPUAttentionImpl(AttentionImpl, torch.nn.Module):
+    """
+    If the input tensors contain prompt tokens, the layout is as follows:
+    |<--------------- num_prefill_tokens ----------------->|
+    |<--prefill_0-->|<--prefill_1-->|...|<--prefill_N-1--->|
+
+    Otherwise, the layout is as follows:
+    |<----------------- num_decode_tokens ------------------>|
+    |<--decode_0-->|..........|<--decode_M-1-->|<--padding-->|
+
+    Generation tokens can contain padding when cuda-graph is used.
+    Currently, prompt tokens don't contain any padding.
+
+    The prompts might have different lengths, while the generation tokens
+    always have length 1.
+    """
+
+    def __init__(
+        self,
+        num_heads: int,
+        head_size: int,
+        scale: float,
+        num_kv_heads: int,
+        alibi_slopes: Optional[List[float]],
+        sliding_window: Optional[int],
+        kv_cache_dtype: str,
+        blocksparse_params: Optional[Dict[str, Any]] = None,
+        max_seq_len: int = 4096,
+    ) -> None:
+        super(AttentionImpl, self).__init__()
+        self.kv_cache_dtype = kv_cache_dtype
+        self.num_heads = num_heads
+        self.head_size = head_size
+        self.scale = float(scale)
+        self.matmul_qk = Matmul()
+        self.softmax = Softmax()
+        self.matmul_av = Matmul()
+        self.k_cache = VLLMKVCache()
+        self.v_cache = VLLMKVCache()
+        self.num_kv_heads = num_heads if num_kv_heads is None else num_kv_heads
+        self.sliding_window = sliding_window
+        self.alibi_slopes = alibi_slopes
+        if alibi_slopes is not None:
+            alibi_slopes_tensor = torch.tensor(alibi_slopes,
+                                               dtype=torch.bfloat16)
+            self.alibi_slopes = alibi_slopes_tensor
+        assert self.num_heads % self.num_kv_heads == 0
+        self.num_queries_per_kv = self.num_heads // self.num_kv_heads
+
+        self.prefill_use_fusedsdpa = os.getenv('VLLM_PROMPT_USE_FUSEDSDPA',
+                                               '1').lower() in ['1', 'true'] \
+                                               and not is_fake_hpu()
+        if self.prefill_use_fusedsdpa:
+            assert alibi_slopes is None, \
+                'Prefill with FusedSDPA not supported with alibi slopes!'
+
+        suppored_head_sizes = HPUPagedAttention.get_supported_head_sizes()
+        if head_size not in suppored_head_sizes:
+            raise ValueError(
+                f"Head size {head_size} is not supported by PagedAttention. "
+                f"Supported head sizes are: {suppored_head_sizes}.")
+
+    def forward(
+        self,
+        query: torch.Tensor,
+        key: torch.Tensor,
+        value: torch.Tensor,
+        kv_cache: torch.Tensor,
+        attn_metadata: HPUAttentionMetadata,
+        k_scale: float = 1.0,
+        v_scale: float = 1.0,
+        attn_type: AttentionType = AttentionType.DECODER,
+    ) -> torch.Tensor:
+        """Forward pass with xFormers and PagedAttention.
+
+        Args:
+            query: shape = [num_tokens, num_heads * head_size]
+            key: shape = [num_tokens, num_kv_heads * head_size]
+            value: shape = [num_tokens, num_kv_heads * head_size]
+            kv_cache = [2, num_blocks, block_size * num_kv_heads * head_size]
+            attn_metadata: Metadata for attention.
+        Returns:
+            shape = [num_tokens, num_heads * head_size]
+        """
+        if attn_type != AttentionType.DECODER:
+            raise NotImplementedError("Encoder self-attention and "
+                                      "encoder/decoder cross-attention "
+                                      "are not implemented for "
+                                      "HPUAttentionImpl")
+        batch_size, seq_len, hidden_size = query.shape
+        _, seq_len_kv, _ = key.shape
+
+        query = query.view(-1, self.num_heads, self.head_size)
+        key = key.view(-1, self.num_kv_heads, self.head_size)
+        value = value.view(-1, self.num_kv_heads, self.head_size)
+        block_indices = attn_metadata.block_indices
+        block_offsets = attn_metadata.block_offsets
+        if attn_metadata.is_prompt:
+            key = key.unflatten(0, (block_indices.size(0), -1))
+            value = value.unflatten(0, (block_indices.size(0), -1))
+        if kv_cache is not None:
+            key_cache, value_cache = HPUPagedAttention.split_kv_cache(
+                kv_cache, self.num_kv_heads, self.head_size)
+
+            # Reshape the input keys and values and store them in the cache.
+            # If kv_cache is not provided, the new key and value tensors are
+            # not cached. This happens during the initial memory profiling run.
+            key_cache = self.k_cache(key, key_cache, block_indices,
+                                     block_offsets)
+            value_cache = self.v_cache(value, value_cache, block_indices,
+                                       block_offsets)
+
+        if attn_metadata.is_prompt:
+            # Prompt run.
+            query_shape = (batch_size, seq_len, self.num_heads, self.head_size)
+            kv_shape = (batch_size, seq_len_kv, self.num_kv_heads,
+                        self.head_size)
+            if attn_metadata is None or attn_metadata.block_list is None:
+                if not self.prefill_use_fusedsdpa:
+                    # TODO: move this outside of model
+                    assert attn_metadata.attn_bias is not None, \
+                            'attn_bias must be set before calling model.forward'
+                    attn_bias = attn_metadata.attn_bias
+                    if self.alibi_slopes is not None:
+                        position_bias = _make_alibi_bias(
+                            self.alibi_slopes, self.num_kv_heads,
+                            attn_bias.dtype, attn_bias.shape[-1])
+                        attn_bias = attn_bias.tile(
+                            (1, self.num_kv_heads, 1, 1))
+                        attn_bias.add_(position_bias)
+                else:
+                    attn_bias = None
+
+                out = ops.prompt_attention(
+                    query.view(query_shape),
+                    key.view(kv_shape),
+                    value.view(kv_shape),
+                    attn_bias=attn_bias,
+                    p=0.0,
+                    scale=self.scale,
+                    matmul_qk_op=self.matmul_qk,
+                    softmax_op=self.softmax,
+                    matmul_av_op=self.matmul_av,
+                )
+            else:
+                # TODO: enable FusedSDPA
+                out = HPUPagedAttention.forward_prefix(
+                    query=query.view(query_shape),
+                    key=key.view(kv_shape),
+                    value=value.view(kv_shape),
+                    key_cache=key_cache,
+                    value_cache=value_cache,
+                    block_list=attn_metadata.block_list,
+                    attn_bias=attn_metadata.attn_bias,
+                    scale=self.scale,
+                    matmul_qk_op=self.matmul_qk,
+                    matmul_av_op=self.matmul_av,
+                    softmax_op=self.softmax,
+                    keys_fetch_func=self.k_cache.fetch_from_cache,
+                    values_fetch_func=self.v_cache.fetch_from_cache)
+            output = out.reshape(batch_size, seq_len, hidden_size)
+        else:
+            # Decoding run.
+            output = HPUPagedAttention.forward_decode(
+                query=query,
+                key_cache=key_cache,
+                value_cache=value_cache,
+                block_list=attn_metadata.block_list,
+                block_mapping=attn_metadata.block_mapping,
+                block_bias=attn_metadata.attn_bias,
+                block_scales=attn_metadata.block_scales,
+                block_groups=attn_metadata.block_groups,
+                scale=self.scale,
+                matmul_qk_op=self.matmul_qk,
+                matmul_av_op=self.matmul_av,
+                keys_fetch_func=self.k_cache.fetch_from_cache,
+                values_fetch_func=self.v_cache.fetch_from_cache)
+        # Reshape the output tensor.
+        return output.view(batch_size, seq_len, hidden_size)
+
+
+def _make_alibi_bias(
+    alibi_slopes: torch.Tensor,
+    num_kv_heads: int,
+    dtype: torch.dtype,
+    seq_len: int,
+) -> torch.Tensor:
+    bias = torch.arange(seq_len, dtype=dtype)
+    # NOTE(zhuohan): HF uses
+    #     `bias = bias[None, :].repeat(seq_len, 1)`
+    # here. We find that both biases give the same results, but
+    # the bias below more accurately follows the original ALiBi
+    # paper.
+    # Calculate a matrix where each element represents ith element- jth
+    # element.
+    bias = bias[None, :] - bias[:, None]
+
+    padded_len = (seq_len + 7) // 8 * 8
+    num_heads = alibi_slopes.shape[0]
+    bias = torch.empty(
+        1,  # batch size
+        num_heads,
+        seq_len,
+        padded_len,
+        device=alibi_slopes.device,
+        dtype=dtype,
+    )[:, :, :, :seq_len].copy_(bias)
+    bias.mul_(alibi_slopes[:, None, None])
+    if num_heads != num_kv_heads:
+        bias = bias.unflatten(1, (num_kv_heads, num_heads // num_kv_heads))
+    return bias

vllm/v1/engine/core.py

@@ -17,7 +17,7 @@
 from vllm.v1.core.scheduler import Scheduler
 from vllm.v1.engine import (EngineCoreOutput, EngineCoreOutputs,
                             EngineCoreRequest, EngineCoreRequestType)
-from vllm.v1.executor.gpu_executor import GPUExecutor
+#from vllm.v1.executor.gpu_executor import GPUExecutor
 from vllm.v1.request import Request, RequestStatus
 from vllm.version import __version__ as VLLM_VERSION
 
@@ -34,7 +34,7 @@ class EngineCore:
     def __init__(
         self,
         vllm_config: VllmConfig,
-        executor_class: Type[GPUExecutor],
+        executor_class: Type[Any],
         usage_context: UsageContext,
     ):
         # Override the configs for V1.
@@ -124,7 +124,7 @@ class EngineCoreProc(EngineCore):
     def __init__(
         self,
         vllm_config: VllmConfig,
-        executor_class: Type[GPUExecutor],
+        executor_class: Type[Any],
         usage_context: UsageContext,
         input_path: str,
         output_path: str,
@@ -209,7 +209,7 @@ def wait_for_startup(
     @staticmethod
     def make_engine_core_process(
         vllm_config: VllmConfig,
-        executor_class: Type[GPUExecutor],
+        executor_class: Type[Any],
         usage_context: UsageContext,
         input_path: str,
         output_path: str,

vllm/v1/engine/llm_engine.py

@@ -1,4 +1,4 @@
-from typing import Dict, List, Mapping, Optional, Type, Union
+from typing import Any, Dict, List, Mapping, Optional, Type, Union
 
 from vllm.config import VllmConfig
 from vllm.engine.arg_utils import EngineArgs
@@ -8,6 +8,7 @@
 from vllm.logger import init_logger
 from vllm.lora.request import LoRARequest
 from vllm.outputs import RequestOutput
+from vllm.platforms import current_platform
 from vllm.pooling_params import PoolingParams
 from vllm.prompt_adapter.request import PromptAdapterRequest
 from vllm.sampling_params import SamplingParams
@@ -16,7 +17,6 @@
 from vllm.v1.engine.core_client import EngineCoreClient
 from vllm.v1.engine.detokenizer import Detokenizer
 from vllm.v1.engine.processor import Processor
-from vllm.v1.executor.gpu_executor import GPUExecutor
 
 logger = init_logger(__name__)
 
@@ -27,7 +27,7 @@ class LLMEngine:
     def __init__(
         self,
         vllm_config: VllmConfig,
-        executor_class: Type[GPUExecutor],
+        executor_class: Type[Any],
         log_stats: bool,
         usage_context: UsageContext = UsageContext.ENGINE_CONTEXT,
         stat_loggers: Optional[Dict[str, StatLoggerBase]] = None,
@@ -92,6 +92,10 @@ def from_engine_args(
 
     @classmethod
     def _get_executor_cls(cls, vllm_config: VllmConfig):
+        if current_platform.is_hpu():
+            from vllm.v1.executor.hpu_executor import HPUExecutor
+            return HPUExecutor
+        from vllm.v1.executor.gpu_executor import GPUExecutor
         return GPUExecutor
 
     def stop_remote_worker_execution_loop(self) -> None: