Add notes about 384 default max_prompt_length

Signed-off-by: Andrea Fasoli <andrea.fasoli@ibm.com>

Author: andrea-fasoli

aiu_fms_testing_utils/utils/args_parsing.py

@@ -176,7 +176,7 @@ def get_args(parser: argparse.ArgumentParser) -> argparse.Namespace:
         help=(
             "Cap the number of tokens per prompt to a maximum length prior to padding. "
             "If None, prompts to decoder models will have no cap, while prompts to "
-            "encoder models will be capped to a default of 384 tokens."
+            "encoder models will be capped to a default of 384 tokens (for QA task)."
         ),
     )
 

aiu_fms_testing_utils/utils/encoders_utils.py

@@ -102,7 +102,7 @@ def prepare_validation_features(
         max_prompt_length = (
             args.max_prompt_length
             if args.max_prompt_length is not None
-            else 384
+            else 384  # this default is targeted at QA task (not a model limitation)
         )
 
         # Some of the questions have lots of whitespace on the left, which is not useful