119 lines
3.7 KiB
Python
119 lines
3.7 KiB
Python
# SPDX-License-Identifier: Apache-2.0
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# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
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from vllm.logger import init_logger
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from vllm.platforms import current_platform
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logger = init_logger(__name__)
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if current_platform.is_cuda():
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from vllm import _custom_ops as ops
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reshape_and_cache_flash = ops.reshape_and_cache_flash
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from vllm.vllm_flash_attn import flash_attn_varlen_func, get_scheduler_metadata
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elif current_platform.is_xpu():
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from vllm._ipex_ops import ipex_ops as ops
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reshape_and_cache_flash = ops.reshape_and_cache_flash
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flash_attn_varlen_func = ops.flash_attn_varlen_func
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get_scheduler_metadata = ops.get_scheduler_metadata
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elif current_platform.is_rocm():
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try:
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from flash_attn import flash_attn_varlen_func # noqa: F401
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except ImportError as e:
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raise ImportError(
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"Rocm platform requires upstream flash-attn "
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"to be installed. Please install flash-attn first."
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) from e
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def get_flash_attn_version(requires_alibi: bool = False) -> int | None:
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# import here to avoid circular dependencies
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from vllm.platforms import current_platform
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if current_platform.is_xpu():
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return 2
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try:
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from vllm.vllm_flash_attn.flash_attn_interface import (
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fa_version_unsupported_reason,
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is_fa_version_supported,
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)
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device_capability = current_platform.get_device_capability()
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assert device_capability is not None
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# 1. default version depending on platform
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fa_version = (
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3 if (device_capability.major == 9 and is_fa_version_supported(3)) else 2
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)
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# 2. override if passed by environment or config
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from vllm.config import get_current_vllm_config
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vllm_config = get_current_vllm_config()
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if vllm_config.attention_config.flash_attn_version is not None:
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fa_version = vllm_config.attention_config.flash_attn_version
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# 3. fallback for unsupported combinations
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if device_capability.major == 10 and fa_version == 3:
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logger.warning_once(
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"Cannot use FA version 3 on Blackwell platform "
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"defaulting to FA version 2."
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)
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fa_version = 2
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if requires_alibi and fa_version == 3:
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logger.warning_once(
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"Cannot use FA version 3 with ALiBi, defaulting to FA version 2."
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)
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fa_version = 2
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if not is_fa_version_supported(fa_version):
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logger.error(
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"Cannot use FA version %d is not supported due to %s",
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fa_version,
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fa_version_unsupported_reason(fa_version),
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)
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assert is_fa_version_supported(fa_version)
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return fa_version
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except (ImportError, AssertionError):
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return None
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def flash_attn_supports_fp8() -> bool:
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return (
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get_flash_attn_version() == 3
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and current_platform.get_device_capability().major == 9
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)
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def flash_attn_supports_sinks() -> bool:
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if current_platform.is_xpu():
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return True
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else:
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return get_flash_attn_version() == 3
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def flash_attn_supports_mla():
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from vllm.platforms import current_platform
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if current_platform.is_cuda():
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try:
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from vllm.vllm_flash_attn.flash_attn_interface import (
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is_fa_version_supported,
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)
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return (
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is_fa_version_supported(3)
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and current_platform.get_device_capability()[0] == 9
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)
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except (ImportError, AssertionError):
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pass
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return False
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def is_flash_attn_varlen_func_available() -> bool:
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return current_platform.is_cuda() or current_platform.is_xpu()
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