Model: Warn user if context > max_seq_len

Unlike other backends, tabby attempts to generate even if the context
is greater than the max sequence length via truncation of the given
context.

Rather than artifically erroring out, give a warning that outputted
console metrics are going to be incorrect and to make sure that
context <= max_seq_len.

Signed-off-by: kingbri <bdashore3@proton.me>

model.py

@@ -336,6 +336,13 @@ class ModelContainer:
             add_bos=kwargs.get("add_bos_token", True),
             encode_special_tokens = True
         )
+        context_len = len(ids[0])
+
+        if context_len > self.config.max_seq_len:
+            print(
+                f"WARNING: The context length {context_len} is greater than the max_seq_len {self.config.max_seq_len}.",
+                "Generation is truncated and metrics may not be accurate."
+            )
 
         # Begin
 
@@ -392,14 +399,18 @@ class ModelContainer:
         elapsed_time = last_chunk_time - start_time
 
         initial_response = f"Response: {round(generated_tokens, 2)} tokens generated in {round(elapsed_time, 2)} seconds"
-        extra_responses = []
+        itemization = []
+        extra_parts = []
 
         # Add tokens per second
-        extra_responses.append(f"{'Indeterminate' if elapsed_time == 0 else round(generated_tokens / elapsed_time, 2)} T/s")
+        itemization.append(f"{'Indeterminate' if elapsed_time == 0 else round(generated_tokens / elapsed_time, 2)} T/s")
 
         # Add context (original token count)
         if ids is not None:
-            extra_responses.append(f"context {len(ids[0])} tokens")
+            itemization.append(f"context {context_len} tokens")
+
+        if context_len > self.config.max_seq_len:
+            extra_parts.append("<-- Not accurate (truncated)")
 
         # Print output
-        print(initial_response + " (" + ", ".join(extra_responses) + ")")
+        print(initial_response + " (" + ", ".join(itemization) + ") " + " ".join(extra_parts))