fix flashattn warning

src/llmtuner/extras/patches/llama_patch.py

@@ -5,11 +5,14 @@ from typing import Optional, Tuple
 from transformers.utils import logging
 from transformers.models.llama.modeling_llama import LlamaAttention, apply_rotary_pos_emb, repeat_kv
 
+is_flash_attn_2_available = False
+
 try:
     from flash_attn import flash_attn_func, flash_attn_varlen_func # type: ignore
     from flash_attn.bert_padding import pad_input, unpad_input # type: ignore
+    is_flash_attn_2_available = True
 except ImportError:
-    print("FlashAttention-2 is not installed, ignore this if you are not using FlashAttention.")
+    is_flash_attn_2_available = False
 
 
 logger = logging.get_logger(__name__)

src/llmtuner/tuner/core/loader.py

@@ -123,9 +123,12 @@ def load_model_and_tokenizer(
     # Set FlashAttention-2
     if model_args.flash_attn:
         if getattr(config, "model_type", None) == "llama":
+            if LlamaPatches.is_flash_attn_2_available:
                 LlamaModule.LlamaAttention = LlamaPatches.LlamaFlashAttention2
                 LlamaModule.LlamaModel._prepare_decoder_attention_mask = LlamaPatches._prepare_decoder_attention_mask
                 logger.info("Using FlashAttention-2 for faster training and inference.")
+            else:
+                logger.warning("FlashAttention-2 is not installed.")
         elif getattr(config, "model_type", None) in ["qwen", "Yi"]:
             logger.info("Current model automatically enables FlashAttention if installed.")
         else: