[CI][MPS] Fix compile benchmark correctness (pytorch#159731)

By passing `fullgraph=True` attribute and increasing cache size limit to 2**16

Otherwise, compiler might decide not to fall back to eager to avoid recompilations
Pull Request resolved: pytorch#159731
Approved by: https://github.com/dcci

Author: malfet

test/bench_mps_ops.py

@@ -90,7 +90,7 @@ def f(t):
         return reduction_func(t, dim=0)
 
     f.__name__ = reduction_func.__name__
-    f_c = torch.compile(f, dynamic=False)
+    f_c = torch.compile(f, dynamic=False, fullgraph=True)
 
     for size in (512, 1024, 2048, 4096):
         x = torch.testing.make_tensor(size, size, device=device, dtype=dtype)
@@ -116,7 +116,7 @@ def bench_scan(
         def f(t):
             return scan_func(t, dim=dim)
 
-        f_c = torch.compile(f, dynamic=False)
+        f_c = torch.compile(f, dynamic=False, fullgraph=True)
 
         for size in (32, 128, 512, 1024):
             f.__name__ = f"{scan_func.__name__}-dim{dim}-{size}x{size}"
@@ -135,7 +135,7 @@ def f(t):
     def f_1d(t):
         return scan_func(t, dim=0)
 
-    f_1d_c = torch.compile(f_1d, dynamic=False)
+    f_1d_c = torch.compile(f_1d, dynamic=False, fullgraph=True)
 
     for size in (100, 10000, 1000000):
         f_1d.__name__ = f"{scan_func.__name__}-1d-{size}"
@@ -204,4 +204,5 @@ def main() -> None:
 
 
 if __name__ == "__main__":
+    torch._dynamo.config.cache_size_limit = 2**16
     main()