[Kernel] Move attn_type to Attention.__init__() (#11690)

Signed-off-by: Chen Zhang <[email protected]>

tests/kernels/test_encoder_decoder_attn.py

@@ -13,8 +13,7 @@
 import torch
 
 from tests.kernels.utils import *
-from vllm.attention import (Attention, AttentionBackend, AttentionMetadata,
-                            AttentionType)
+from vllm.attention import Attention, AttentionMetadata, AttentionType
 from vllm.attention.backends.utils import STR_NOT_IMPL_ENC_DEC_ROCM_HIP
 from vllm.attention.selector import (_Backend, _cached_get_attn_backend,
                                      global_force_attn_backend_context_manager)
@@ -64,6 +63,7 @@ class TestPoint(NamedTuple):
     max_dec_seq_len: int
     max_enc_seq_len: int
     num_blocks: int
+    attn_type: AttentionType
 
 
 class TestResources(NamedTuple):
@@ -96,7 +96,6 @@ class TestResources(NamedTuple):
     '''
 
     scale: float
-    attn_backend: AttentionBackend
     attn: Attention
     kv_cache: torch.Tensor
 
@@ -129,16 +128,17 @@ class that Attention will automatically select when it is constructed.
     '''
 
     scale = float(1.0 / (test_pt.head_size**0.5))
-    attn_backend = make_backend(test_pt.backend_name)
     attn = Attention(
         test_pt.num_heads,
         test_pt.head_size,
         scale=scale,
+        prefix=f"{test_pt.attn_type}",
+        attn_type=test_pt.attn_type,
     )
     if test_pt.num_blocks is None or test_pt.num_heads is None:
         # Caller does not require a KV cache
         return TestResources(
-            scale, attn_backend, attn,
+            scale, attn,
             torch.tensor([], dtype=torch.float32, device=CUDA_DEVICE))
 
     # Construct KV cache
@@ -148,7 +148,7 @@ class that Attention will automatically select when it is constructed.
                              test_pt.block_size,
                              device=CUDA_DEVICE,
                              backend=test_pt.backend_name)
-    return TestResources(scale, attn_backend, attn, kv_cache)
+    return TestResources(scale, attn, kv_cache)
 
 
 def _encoder_attn_setup(
@@ -193,6 +193,7 @@ def _encoder_attn_setup(
         _,
         max_q_seq_len,
         _,
+        _,
     ) = test_pt
 
     scale = test_rsrcs.scale
@@ -301,6 +302,7 @@ def _decoder_attn_setup(
         max_q_seq_len,
         _,
         _,
+        _,
     ) = test_pt
 
     scale = test_rsrcs.scale
@@ -488,6 +490,7 @@ def _enc_dec_cross_attn_setup_reuses_query(
         max_decoder_seq_len,
         max_encoder_seq_len,
         _,
+        _,
     ) = test_pt
 
     scale = test_rsrcs.scale
@@ -622,7 +625,6 @@ def _run_encoder_attention_test(
       & attn_metadata
     '''
     assert attn_metadata.num_decode_tokens == 0
-    attn_type = AttentionType.ENCODER
     packed_qkv = encoder_test_params.packed_qkvo.packed_qkv
     assert packed_qkv is not None
     with set_forward_context(attn_metadata, vllm_config):
@@ -635,14 +637,11 @@ def _run_encoder_attention_test(
         # is shaped as [num_tokens, hidden_size] and we can skip the reshape.
         reshaped_query = packed_qkv.query.view(
             -1, test_pt.num_heads * test_pt.head_size)
-        return attn.forward(reshaped_query,
-                            packed_qkv.key,
-                            packed_qkv.value,
-                            torch.tensor([],
-                                         dtype=torch.float32,
-                                         device=packed_qkv.query.device),
-                            attn_metadata,
-                            attn_type=attn_type)
+        return attn.forward(
+            reshaped_query, packed_qkv.key, packed_qkv.value,
+            torch.tensor([],
+                         dtype=torch.float32,
+                         device=packed_qkv.query.device), attn_metadata)
 
 
 def _run_decoder_self_attention_test(
@@ -675,7 +674,6 @@ def _run_decoder_self_attention_test(
     * Attention.forward() applied to packed_{query,key,value}, kv_cache
       & attn_metadata
     '''
-    attn_type = AttentionType.DECODER
     attn = test_rsrcs.attn
     kv_cache = test_rsrcs.kv_cache
     packed_qkv = decoder_test_params.packed_qkvo.packed_qkv
@@ -690,12 +688,8 @@ def _run_decoder_self_attention_test(
         # is shaped as [num_tokens, hidden_size] and we can skip the reshape.
         reshaped_query = packed_qkv.query.view(
             -1, test_pt.num_heads * test_pt.head_size)
-        return attn.forward(reshaped_query,
-                            packed_qkv.key,
-                            packed_qkv.value,
-                            kv_cache,
-                            attn_metadata,
-                            attn_type=attn_type)
+        return attn.forward(reshaped_query, packed_qkv.key, packed_qkv.value,
+                            kv_cache, attn_metadata)
 
 
 def _run_encoder_decoder_cross_attention_test(
@@ -742,7 +736,6 @@ def _run_encoder_decoder_cross_attention_test(
     '''
     assert decoder_test_params.packed_qkvo.packed_qkv is not None
 
-    attn_type = AttentionType.ENCODER_DECODER
     attn = test_rsrcs.attn
     kv_cache = test_rsrcs.kv_cache
     if cross_test_params is None:
@@ -762,12 +755,8 @@ def _run_encoder_decoder_cross_attention_test(
         # is shaped as [num_tokens, hidden_size] and we can skip the reshape.
         reshaped_query = decoder_test_params.packed_qkvo.packed_qkv.query.view(
             -1, test_pt.num_heads * test_pt.head_size)
-        return attn.forward(reshaped_query,
-                            key,
-                            value,
-                            kv_cache,
-                            attn_metadata,
-                            attn_type=attn_type)
+        return attn.forward(reshaped_query, key, value, kv_cache,
+                            attn_metadata)
 
 
 @pytest.fixture(autouse=True)
@@ -839,7 +828,7 @@ def test_encoder_only(
         # is not part of this test
         test_pt = TestPoint(num_heads, head_size, attn_backend.name,
                             batch_size, block_size, max_dec_seq_len,
-                            max_enc_seq_len, 4096)
+                            max_enc_seq_len, 4096, AttentionType.ENCODER)
 
         # Attention scale factor, attention backend instance, attention wrapper
         # instance, KV cache init
@@ -855,7 +844,7 @@ def test_encoder_only(
         # Shared prefill metadata structure
 
         prephase_attn_metadata: AttentionMetadata = make_test_metadata(
-            test_rsrcs.attn_backend,
+            attn_backend,
             True,
             None,
             decoder_test_params=None,
@@ -961,20 +950,29 @@ def test_e2e_enc_dec_attn(
         # Note: KV cache size of 4096 is arbitrary & chosen intentionally
         # to be more than necessary, since exceeding the kv cache size
         # is not part of this test
-        test_pt = TestPoint(num_heads, head_size, attn_backend.name,
-                            batch_size, block_size, max_dec_seq_len,
-                            max_enc_seq_len, 4096)
+        enc_test_pt = TestPoint(num_heads, head_size, attn_backend.name,
+                                batch_size, block_size, max_dec_seq_len,
+                                max_enc_seq_len, 4096, AttentionType.ENCODER)
+        enc_dec_test_pt = TestPoint(num_heads, head_size, attn_backend.name,
+                                    batch_size, block_size, max_dec_seq_len,
+                                    max_enc_seq_len, 4096,
+                                    AttentionType.ENCODER_DECODER)
+        dec_test_pt = TestPoint(num_heads, head_size, attn_backend.name,
+                                batch_size, block_size, max_dec_seq_len,
+                                max_enc_seq_len, 4096, AttentionType.DECODER)
 
         # Attention scale factor, attention backend instance, attention wrapper
         # instance, KV cache init
         vllm_config = VllmConfig()
         with set_current_vllm_config(vllm_config):
-            test_rsrcs = _make_test_resources(test_pt)
+            enc_test_rsrcs = _make_test_resources(enc_test_pt)
+            enc_dec_test_rsrcs = _make_test_resources(enc_dec_test_pt)
+            dec_test_rsrcs = _make_test_resources(dec_test_pt)
 
         # Construct encoder attention test params (only used
         # during prefill)
 
-        enc_test_params = _encoder_attn_setup(test_pt, test_rsrcs)
+        enc_test_params = _encoder_attn_setup(enc_test_pt, enc_test_rsrcs)
 
         # Construct Decoder self-attention prefill-phase & decode-phase
         # test params, including query/key/value tensors, decoder self-attention
@@ -987,7 +985,7 @@ def test_e2e_enc_dec_attn(
             prephase_dec_test_params,
             decphase_dec_test_params,
             cross_block_base_addr,
-        ) = _decoder_attn_setup(test_pt, test_rsrcs)
+        ) = _decoder_attn_setup(dec_test_pt, dec_test_rsrcs)
 
         # Construct encoder/decoder cross-attention prefill-phase
         # & decode-phase test params, including key/value tensors,
@@ -1000,14 +998,14 @@ def test_e2e_enc_dec_attn(
             dec_qkv,
             enc_test_params,
             prephase_dec_test_params,
-            test_pt,
-            test_rsrcs,
+            enc_dec_test_pt,
+            enc_dec_test_rsrcs,
             block_base_addr=cross_block_base_addr)
 
         # Shared prefill metadata structure
         assert prephase_dec_test_params.packed_qkvo.packed_qkv is not None
         prephase_attn_metadata: AttentionMetadata = make_test_metadata(
-            test_rsrcs.attn_backend,
+            attn_backend,
             True,
             prephase_dec_test_params.packed_qkvo.packed_qkv.q_seq_lens,
             decoder_test_params=prephase_dec_test_params,
@@ -1017,10 +1015,10 @@ def test_e2e_enc_dec_attn(
 
         # PREFILL: encoder attention
 
-        enc_pckd_act_out = _run_encoder_attention_test(test_rsrcs.attn,
+        enc_pckd_act_out = _run_encoder_attention_test(enc_test_rsrcs.attn,
                                                        enc_test_params,
                                                        prephase_attn_metadata,
-                                                       test_pt=test_pt,
+                                                       test_pt=enc_test_pt,
                                                        vllm_config=vllm_config)
 
         # - Is encoder attention result correct?
@@ -1030,10 +1028,10 @@ def test_e2e_enc_dec_attn(
         # PREFILL: decoder self-attention test
 
         prephase_dec_pckd_act_out = _run_decoder_self_attention_test(
-            test_rsrcs,
+            dec_test_rsrcs,
             prephase_dec_test_params,
             prephase_attn_metadata,
-            test_pt=test_pt,
+            test_pt=dec_test_pt,
             vllm_config=vllm_config)
 
         # - Is prefill decoder self-attention correct?
@@ -1044,11 +1042,11 @@ def test_e2e_enc_dec_attn(
         # PREFILL: encoder/decoder cross-attention test
 
         prephase_cross_pckd_act_out = _run_encoder_decoder_cross_attention_test(
-            test_rsrcs,
+            enc_dec_test_rsrcs,
             prephase_dec_test_params,
             prephase_cross_test_params,
             prephase_attn_metadata,
-            test_pt=test_pt,
+            test_pt=enc_dec_test_pt,
             vllm_config=vllm_config)
 
         # - Is prefill encoder/decoder cross-attention correct?
@@ -1059,7 +1057,7 @@ def test_e2e_enc_dec_attn(
         # DECODE: build decode-phase attention metadata
 
         decphase_attn_metadata: AttentionMetadata = make_test_metadata(
-            test_rsrcs.attn_backend,
+            attn_backend,
             False,
             dec_qkv.q_seq_lens,
             decoder_test_params=decphase_dec_test_params,
@@ -1070,10 +1068,10 @@ def test_e2e_enc_dec_attn(
         # DECODE: decoder self-attention test
 
         decphase_dec_pckd_act_out = _run_decoder_self_attention_test(
-            test_rsrcs,
+            dec_test_rsrcs,
             decphase_dec_test_params,
             decphase_attn_metadata,
-            test_pt=test_pt,
+            test_pt=dec_test_pt,
             vllm_config=vllm_config)
 
         # - Is decode-phase decoder self-attention correct?
@@ -1084,11 +1082,11 @@ def test_e2e_enc_dec_attn(
         # DECODE: encoder/decoder cross-attention test
 
         decphase_cross_pckd_act_out = _run_encoder_decoder_cross_attention_test(
-            test_rsrcs,
+            enc_dec_test_rsrcs,
             decphase_dec_test_params,
             None,
             decphase_attn_metadata,
-            test_pt=test_pt,
+            test_pt=enc_dec_test_pt,
             vllm_config=vllm_config)
 
         # - Is decode-phase encoder/decoder cross-attention correct?

tests/kernels/utils.py

@@ -13,6 +13,7 @@
 
 from vllm.attention import AttentionBackend, AttentionMetadata, AttentionType
 from vllm.model_executor.layers.activation import SiluAndMul
+from vllm.platforms.interface import _Backend
 from vllm.utils import (STR_BACKEND_ENV_VAR, STR_FLASH_ATTN_VAL,
                         STR_XFORMERS_ATTN_VAL, make_tensor_with_pad)
 
@@ -790,7 +791,7 @@ def make_block_tables_slot_mapping(
 
 
 def make_test_metadata(
-    attn_backend: AttentionBackend,
+    attn_backend: _Backend,
     is_prompt: bool,
     seq_lens: Optional[List[int]],
     decoder_test_params: Optional[PhaseTestParameters],
@@ -815,7 +816,7 @@ def make_test_metadata(
 
     Arguments:
 
-    * attn_backend: Backend for sourcing attention kernels
+    * attn_backend_name: Backend for sourcing attention kernels
     * is_prompt: prefill if True, o/w decode
     * seq_lens: list of token counts for each sequence
     * decoder_test_params: decoder self-attention test params; 
@@ -882,6 +883,8 @@ def make_test_metadata(
         #   (kv_mmap)
         cross_kv_mmap = cross_test_params.kv_mmap
 
+    attn_backend_obj = make_backend(attn_backend.name)
+
     if is_prompt:
         # Prefill-phase scenario
 
@@ -902,8 +905,7 @@ def make_test_metadata(
                                    context_lens,
                                    encoder_seq_lens,
                                    device=device)
-
-        return attn_backend.make_metadata(
+        return attn_backend_obj.make_metadata(
             num_prefills=num_prefills,
             slot_mapping=(None if kv_mmap is None else kv_mmap.slot_mapping),
             multi_modal_placeholder_index_maps=None,
@@ -952,7 +954,7 @@ def make_test_metadata(
                                    encoder_seq_lens,
                                    device=device)
 
-        return attn_backend.make_metadata(
+        return attn_backend_obj.make_metadata(
             num_prefills=num_prefills,
             slot_mapping=kv_mmap.slot_mapping,
             multi_modal_placeholder_index_maps=None,

vllm/attention/backends/abstract.py

@@ -233,6 +233,7 @@ def __init__(
         kv_cache_dtype: str = "auto",
         blocksparse_params: Optional[Dict[str, Any]] = None,
         logits_soft_cap: Optional[float] = None,
+        attn_type: str = AttentionType.DECODER,
     ) -> None:
         raise NotImplementedError
 
@@ -246,7 +247,6 @@ def forward(
         attn_metadata: T,
         k_scale: float = 1.0,
         v_scale: float = 1.0,
-        attn_type: str = AttentionType.DECODER,
         output: Optional[torch.Tensor] = None,
     ) -> torch.Tensor:
         raise NotImplementedError