Merge branch 'oom' into 'main'

Adding checks for total number of tokens to keep server from crashing

See merge request ADLR/megatron-lm!428

megatron/text_generation/generation.py

@@ -28,6 +28,8 @@ from .forward_step import ForwardStep
 from .sampling import sample
 from .beam_utils import BeamHypotheses
 
+MAX_TOKENS_TO_OOM = 12000  # (rprenger) Perfect value depends on hardware and network
+
 def score_and_return_on_first_stage(model, tokens, lengths):
     """Function for just scoring.
     Arguments:
@@ -133,11 +135,12 @@ def generate_tokens_probs_and_return_on_first_stage(
     batch_size = tokens.size(0)
     min_prompt_length = lengths.min().item()
     max_sequence_length = tokens.size(1)
-    max_sequence_length = min(max_sequence_length, args.max_position_embeddings)
+
+    if max_sequence_length > args.max_position_embeddings:
+        raise ValueError("Length of prompt + tokens_to_generate longer than allowed")
     
-    # If the context is too big, this happens
-    if min_prompt_length >= max_sequence_length:
-        raise ValueError("context length + tokens_to_generate too large")
+    if max_sequence_length * batch_size >= MAX_TOKENS_TO_OOM:
+        raise ValueError("Too many tokens.  " + str(max_sequence_length*batch_size)+ " is greater than "+str(MAX_TOKENS_TO_OOM))
 
     # forward step.
     forward_step = ForwardStep(model, batch_size, max_sequence_length)

megatron/text_generation_server.py

@@ -226,7 +226,7 @@ class MegatronGenerate(Resource):
                         "logprobs": response_logprobs})
 
             except ValueError as ve:
-                return "Length of prompt + tokens_to_generate longer than allowed"
+                return ve.args[0]
             print("end time: ", datetime.datetime.now())