[Doc] Consistent naming of attention backends (#9498)

Signed-off-by: Thomas Parnell <tpa@zurich.ibm.com>

vllm/attention/backends/flash_attn.py

@@ -32,7 +32,7 @@ class FlashAttentionBackend(AttentionBackend):
 
     @staticmethod
     def get_name() -> str:
-        return "flash-attn"
+        return "FLASH_ATTN"
 
     @staticmethod
     def get_impl_cls() -> Type["FlashAttentionImpl"]:

vllm/attention/backends/flashinfer.py

@@ -40,7 +40,7 @@ class FlashInferBackend(AttentionBackend):
 
     @staticmethod
     def get_name() -> str:
-        return "flashinfer"
+        return "FLASHINFER"
 
     @staticmethod
     def get_impl_cls() -> Type["FlashInferImpl"]:

vllm/attention/backends/ipex_attn.py

@@ -19,7 +19,7 @@ class IpexAttnBackend(AttentionBackend):
 
     @staticmethod
     def get_name() -> str:
-        return "ipex-attn"
+        return "IPEX"
 
     @staticmethod
     def get_impl_cls() -> Type["IpexAttnBackendImpl"]:

vllm/attention/backends/openvino.py

@@ -38,7 +38,7 @@ class OpenVINOAttentionBackend(AttentionBackend):
 
     @staticmethod
     def get_name() -> str:
-        return "openvino"
+        return "OPENVINO"
 
     @staticmethod
     def get_impl_cls():

vllm/attention/backends/pallas.py

@@ -11,6 +11,10 @@ from vllm.attention.backends.utils import CommonAttentionState
 
 class PallasAttentionBackend(AttentionBackend):
 
+    @staticmethod
+    def get_name() -> str:
+        return "PALLAS"
+
     @staticmethod
     def get_impl_cls() -> Type["PallasAttentionBackendImpl"]:
         return PallasAttentionBackendImpl

vllm/attention/backends/placeholder_attn.py

@@ -20,7 +20,7 @@ class PlaceholderAttentionBackend(AttentionBackend):
 
     @staticmethod
     def get_name() -> str:
-        return "placeholder-attn"
+        return "NO_ATTENTION"
 
     @staticmethod
     def get_impl_cls() -> Type["PlaceholderAttentionImpl"]:

vllm/attention/backends/rocm_flash_attn.py

@@ -28,7 +28,7 @@ class ROCmFlashAttentionBackend(AttentionBackend):
 
     @staticmethod
     def get_name() -> str:
-        return "rocm-flash-attn"
+        return "ROCM_FLASH"
 
     @staticmethod
     def get_impl_cls() -> Type["ROCmFlashAttentionImpl"]:

vllm/attention/backends/torch_sdpa.py

@@ -25,7 +25,7 @@ class TorchSDPABackend(AttentionBackend):
 
     @staticmethod
     def get_name() -> str:
-        return "torch-sdpa"
+        return "TORCH_SDPA"
 
     @staticmethod
     def get_impl_cls() -> Type["TorchSDPABackendImpl"]:

vllm/attention/backends/utils.py

@@ -317,8 +317,8 @@ class CommonAttentionState(AttentionState):
         if is_encoder_decoder_model:
             # The encoder decoder model works only with XFormers backend.
             # Assert the same.
-            assert self.runner.attn_backend.get_name() == "xformers", \
+            assert self.runner.attn_backend.get_name() == "XFORMERS", \
-            f"Expected attn_backend name to be 'xformers', but "\
+            f"Expected attn_backend name to be 'XFORMERS', but "\
             f" got '{self.runner.attn_backend.get_name()}'"
             self._update_captured_metadata_for_enc_dec_model(
                 batch_size=batch_size, attn_metadata=attn_metadata)
@@ -337,8 +337,8 @@ class CommonAttentionState(AttentionState):
         if is_encoder_decoder_model:
             # The encoder decoder model works only with XFormers backend.
             # Assert the same.
-            assert self.runner.attn_backend.get_name() == "xformers", \
+            assert self.runner.attn_backend.get_name() == "XFORMERS", \
-            f"Expected attn_backend name to be 'xformers', but "\
+            f"Expected attn_backend name to be 'XFORMERS', but "\
             f" got '{self.runner.attn_backend.get_name()}'"
             self._add_additonal_input_buffers_for_enc_dec_model(
                 attn_metadata=attn_metadata, input_buffers=input_buffers)
@@ -356,8 +356,8 @@ class CommonAttentionState(AttentionState):
         if is_encoder_decoder_model:
             # The encoder decoder model works only with XFormers backend.
             # Assert the same.
-            assert self.runner.attn_backend.get_name() == "xformers", \
+            assert self.runner.attn_backend.get_name() == "XFORMERS", \
-            f"Expected attn_backend name to be 'xformers', but "\
+            f"Expected attn_backend name to be 'XFORMERS', but "\
             f" got '{self.runner.attn_backend.get_name()}'"
             self._prepare_input_buffers_for_enc_dec_model(
                 attn_metadata, input_buffers)

vllm/attention/backends/xformers.py

@@ -24,7 +24,7 @@ class XFormersBackend(AttentionBackend):
 
     @staticmethod
     def get_name() -> str:
-        return "xformers"
+        return "XFORMERS"
 
     @staticmethod
     def get_impl_cls() -> Type["XFormersImpl"]:

vllm/spec_decode/draft_model_runner.py

@@ -179,7 +179,7 @@ class TP1DraftModelRunner(ModelRunner):
                 return False
 
         # TODO: Add support for other attn backends
-        if self.attn_backend.get_name() != "flash-attn":
+        if self.attn_backend.get_name() != "FLASH_ATTN":
             return False
 
         # TODO: Add support for LORA

vllm/spec_decode/spec_decode_worker.py

@@ -184,7 +184,7 @@ class SpecDecodeWorker(LoraNotSupportedWorkerBase):
 
         if not disable_mqa_scorer:
             if scorer_worker.model_runner.attn_backend.get_name(
-            ) != "flash-attn":
+            ) != "FLASH_ATTN":
                 disable_mqa_scorer = True
                 logger.info(
                     "[Speculative Decoding] Disabling MQA scorer as the "

vllm/worker/model_runner.py

@@ -1855,7 +1855,7 @@ class CUDAGraphRunner(nn.Module):
         self.input_buffers["input_ids"].copy_(input_ids, non_blocking=True)
         self.input_buffers["positions"].copy_(positions, non_blocking=True)
 
-        if self.backend_name != "placeholder-attn":
+        if self.backend_name != "NO_ATTENTION":
             self.input_buffers["slot_mapping"].copy_(
                 attn_metadata.slot_mapping, non_blocking=True)
 

vllm/worker/multi_step_model_runner.py

@@ -29,8 +29,8 @@ if TYPE_CHECKING:
 
 logger = init_logger(__name__)
 
-MULTI_STEP_ATTENTION_BACKENDS = ["flash-attn", "rocm-flash-attn", "flashinfer"]
+MULTI_STEP_ATTENTION_BACKENDS = ["FLASH_ATTN", "ROCM_FLASH", "FLASHINFER"]
-MULTI_STEP_CHUNKED_PREFILL_ATTENTION_BACKENDS = ["flash-attn"]
+MULTI_STEP_CHUNKED_PREFILL_ATTENTION_BACKENDS = ["FLASH_ATTN"]
 
 def _get_supported_attention_backends(chunked_prefill_enabled: bool) \
     -> List[str]: