Qualcomm AI Engine Direct - Refactor calibration flow (#13150)

Summary:
- Update calibration flow to enhance the speed of wikitext calibration

cc: @haowhsu-quic , @winskuo-quic

Author: shewu-quic

examples/qualcomm/oss_scripts/llama/decoder_utils.py

@@ -219,37 +219,42 @@ def post_process():
 
 
 def smart_mask_updater(
-    ar_len, atten_mask, pos, k_caches, v_caches, new_k_caches, new_v_caches
+    _, n_updates, atten_mask, pos, k_caches, v_caches, new_k_caches, new_v_caches
 ):
-    # Update the KV cache input for the next inference when the position exceeds the autoregressive length.
-    if pos >= ar_len:
+    # ar_len is unused in smart mask
+    max_cache_len = k_caches[0].size(-1)
+    if pos + n_updates <= max_cache_len:
         for i, k_cache in enumerate(k_caches):
-            k_cache[:, :, pos - ar_len] = new_k_caches[i][:, :, 0]
+            k_cache[:, :, pos : pos + n_updates] = new_k_caches[i][:, :, :n_updates]
 
         for i, v_cache in enumerate(v_caches):
-            v_cache[:, pos - ar_len, :] = new_v_caches[i][:, 0, :]
-        atten_mask[:, :, pos - ar_len] = 0
+            v_cache[:, pos : pos + n_updates, :] = new_v_caches[i][:, :n_updates, :]
+        atten_mask[:, :, pos : pos + n_updates] = 0
+    pos += n_updates
 
-    pos += 1
     return (atten_mask, pos, k_caches, v_caches)
 
 
 def shift_pointer_updater(
-    ar_len, atten_mask, pos, k_caches, v_caches, new_k_caches, new_v_caches
+    ar_len, n_updates, atten_mask, pos, k_caches, v_caches, new_k_caches, new_v_caches
 ):
-    # Update the KV cache input for the next inference when the position exceeds the autoregressive length.
-    if pos >= ar_len:
+    max_cache_len = k_caches[0].size(-1)
+    if pos + n_updates <= max_cache_len:
         k_caches = [
-            torch.cat([k_cache[:, :, 1:], new_k_caches[i][:, :, :1]], dim=-1)
+            torch.cat(
+                [k_cache[:, :, n_updates:], new_k_caches[i][:, :, :n_updates]], dim=-1
+            )
             for i, k_cache in enumerate(k_caches)
         ]
         v_caches = [
-            torch.cat([v_cache[:, 1:, :], new_v_caches[i][:, :1, :]], dim=1)
+            torch.cat(
+                [v_cache[:, n_updates:, :], new_v_caches[i][:, :n_updates, :]], dim=1
+            )
             for i, v_cache in enumerate(v_caches)
         ]
-        atten_mask[:, :, -pos - 1] = 0
+        atten_mask[:, :, -pos - n_updates - ar_len : -pos - ar_len] = 0
+    pos += n_updates
 
-    pos += 1
     return (atten_mask, pos, k_caches, v_caches)
 
 
@@ -269,70 +274,121 @@ def kv_inference(
     # TODO: change criteria & support batch inputs if necessary
     all_pos = torch.arange(0, max_seq_len, 1, dtype=torch.int32).unsqueeze(0)
 
-    token_list, result_logits = [], []
+    prompt_token_list, total_token_list, result_logits = [], [], []
 
     if isinstance(prompt, str):
         # Llama2 tokenizer has no special tokens
         if isinstance(tokenizer, (SentencePieceTokenizer, HuggingFaceTokenizer)):
-            token_list = tokenizer.encode(prompt, bos=True, eos=False)
+            prompt_token_list = tokenizer.encode(prompt, bos=True, eos=False)
         elif isinstance(tokenizer, TiktokenTokenizer):
-            token_list = tokenizer.encode(
+            prompt_token_list = tokenizer.encode(
                 prompt, bos=True, eos=False, allowed_special="all"
             )
         else:
             raise RuntimeError("Unknown tokenizer")
     else:
         # pyre-ignore
-        token_list = prompt.flatten().tolist()
-    pos = len(token_list) if len(token_list) < ar_len else ar_len
+        prompt_token_list = prompt.flatten().tolist()
+    total_token_list = prompt_token_list
     dtype = torch.int64 if use_i64_token else torch.int32
 
     with torch.no_grad():
-        while token_list[-1] != tokenizer.eos_id and pos < max_seq_len:
-            tmp_token_list = torch.tensor(
-                token_list[pos - ar_len : pos], dtype=dtype
-            ).reshape(1, -1)
-            tmp_pos = all_pos[:, pos - ar_len : pos]
-            tmp_atten_mask = atten_mask
-            if pos < ar_len:
-                tmp_token_list = torch.cat(
-                    [
-                        torch.zeros((1, ar_len - pos), dtype=dtype),
-                        torch.tensor(token_list, dtype=dtype).reshape(1, -1),
-                    ],
-                    dim=1,
-                )
-                tmp_pos = torch.cat(
-                    [
-                        torch.zeros((1, ar_len - pos), dtype=torch.int32),
-                        all_pos[:, :pos],
-                    ],
-                    dim=1,
-                )
-                tmp_atten_mask = torch.cat(
-                    [
-                        torch.ones(1, ar_len, max_seq_len - pos) * -255.0,
-                        atten_mask[:, :, -pos:],
-                    ],
-                    dim=-1,
-                )
+        # Phase 1: Prefill the prompt in ar_len chunks.
+        num_prompt_tokens = len(prompt_token_list)
+        pos = 0  # Tracks how many prompt tokens have been processed.
+        while pos < num_prompt_tokens:
+            chunk_start_idx = pos
+            # Take a chunk of prompt tokens, up to ar_len length.
+            chunk_end_idx = min(num_prompt_tokens, pos + ar_len)
+            actual_chunk_tokens = prompt_token_list[chunk_start_idx:chunk_end_idx]
+            num_tokens_in_chunk = len(actual_chunk_tokens)
+
+            # Prepare tmp_token_list (padded with zeros).
+            tmp_token_list = torch.zeros((1, ar_len), dtype=dtype)
+            tmp_token_list[0, :num_tokens_in_chunk] = torch.tensor(
+                actual_chunk_tokens, dtype=dtype
+            )
 
+            # Prepare tmp_pos (padded with zeros).
+            tmp_pos = torch.zeros((1, ar_len), dtype=torch.int32)
+            tmp_pos[0, :num_tokens_in_chunk] = all_pos[
+                0,
+                pos : pos + num_tokens_in_chunk,
+            ]
+
+            # Run inference.
             logits, new_k_caches, new_v_caches = module(
                 tmp_token_list,
-                tmp_atten_mask,
+                atten_mask,
                 tmp_pos,
                 *k_caches,
                 *v_caches,
             )
             if collect_logits:
-                result_logits.append(logits)
+                result_logits.append(logits[:, :num_tokens_in_chunk])
+
+            # Update the pos, KV cache and attention mask.
             atten_mask, pos, k_caches, v_caches = kv_updater(
-                ar_len, atten_mask, pos, k_caches, v_caches, new_k_caches, new_v_caches
+                ar_len,
+                num_tokens_in_chunk,
+                atten_mask,
+                pos,
+                k_caches,
+                v_caches,
+                new_k_caches,
+                new_v_caches,
+            )
+        # Append the last run logits to the total_token_list.
+        total_token_list.append(
+            torch.argmax(logits[:, num_tokens_in_chunk - 1], dim=-1).item()
+        )
+
+        # Phase 2: Generate tokens until the EOS token is generated or max_seq_len is reached.
+        # When run on wikitext for ppl evaluation, this while-loop is not expected to run.
+        max_cache_len = max_seq_len - ar_len
+        num_tokens = len(total_token_list)
+        while total_token_list[-1] != tokenizer.eos_id and num_tokens < max_seq_len:
+            chunk_start_idx = min(pos, max_cache_len)
+            # Take a chunk of generated tokens, up to ar_len length.
+            chunk_end_idx = num_tokens
+            actual_chunk_tokens = total_token_list[chunk_start_idx:chunk_end_idx]
+            num_tokens_in_chunk = len(actual_chunk_tokens)
+
+            # Prepare tmp_token_list (padded with zeros).
+            tmp_token_list = torch.zeros((1, ar_len), dtype=dtype)
+            tmp_token_list[0, :num_tokens_in_chunk] = torch.tensor(
+                actual_chunk_tokens, dtype=dtype
+            )
+
+            # Prepare tmp_pos (padded with zeros).
+            tmp_pos = torch.zeros((1, ar_len), dtype=torch.int32)
+            tmp_pos[0, :num_tokens_in_chunk] = all_pos[0, chunk_start_idx:chunk_end_idx]
+
+            logits, new_k_caches, new_v_caches = module(
+                tmp_token_list,
+                atten_mask,
+                tmp_pos,
+                *k_caches,
+                *v_caches,
             )
-            if pos > len(token_list):
-                token_list.append(torch.argmax(logits[:, -1], dim=-1).item())
+            if collect_logits:
+                result_logits.append(logits[:, :num_tokens_in_chunk])
 
-    logging.info(f"kv inference result:\n{tokenizer.decode(token_list)}")
+            atten_mask, pos, k_caches, v_caches = kv_updater(
+                ar_len,
+                1,
+                atten_mask,
+                pos,
+                k_caches,
+                v_caches,
+                new_k_caches,
+                new_v_caches,
+            )
+            total_token_list.append(
+                torch.argmax(logits[:, num_tokens_in_chunk - 1], dim=-1).item()
+            )
+            num_tokens = len(total_token_list)
+    logging.info(f"kv inference result:\n{tokenizer.decode(total_token_list)}")
     if collect_logits:
         result_logits = torch.cat(result_logits, dim=1)
     return result_logits