[V1] Implement sliding window attention in kv_cache_manager (#14097)

Signed-off-by: Chen Zhang <zhangch99@outlook.com>

Author: heheda12345

tests/core/block/e2e/test_correctness_sliding_window.py

@@ -129,12 +129,16 @@ def test_sliding_window_chunked_prefill(test_llm_generator, batch_size, seed,
     check_answers(indices, answer, test_texts)
 
 
-def prep_prompts(batch_size: int):
+def prep_prompts(batch_size: int, ln_range: tuple[int, int] = (800, 1100)):
     """
     Generate prompts which a bunch of assignments,
     then asking for the value of one of them.
     The prompt is just under 10k tokens; sliding window is 4k
     so the answer is outside sliding window, but should still be correct.
+
+    Args:
+        batch_size: number of prompts to generate
+        ln_range: an argument to control the length of the prompt
     """
     prompts: list[str] = []
     answer: list[int] = []
@@ -145,7 +149,7 @@ def prep_prompts(batch_size: int):
         indices.append(idx)
         prompt = "```python\n# We set a number of variables, " + \
                  f"x{idx} will be important later\n"
-        ln = random.randint(800, 1100)
+        ln = random.randint(*ln_range)
         for k in range(30, ln):
             v = random.randint(10, 99)
             if k == idx:
@@ -157,7 +161,10 @@ def prep_prompts(batch_size: int):
     return prompts, answer, indices
 
 
-def check_answers(indices: list[int], answer: list[int], outputs: list[str]):
+def check_answers(indices: list[int],
+                  answer: list[int],
+                  outputs: list[str],
+                  accept_rate: float = 0.7):
     answer2 = [int(text[0:2].strip()) for text in outputs]
     print(list(zip(indices, zip(answer, answer2))))
     numok = 0
@@ -166,7 +173,7 @@ def check_answers(indices: list[int], answer: list[int], outputs: list[str]):
             numok += 1
     frac_ok = numok / len(answer)
     print(f"Num OK: {numok}/{len(answer)} {frac_ok}")
-    assert frac_ok > 0.7
+    assert frac_ok >= accept_rate
 
 
 def check_window(prompts: list[str]):