add debugging code

python/test/executor_test.py

@@ -166,9 +166,11 @@ def build_bufs(
     else:
         input_buf = GpuBuffer(nelems_input, dtype=dtype)
 
+    in_place = False
+
     test_buf = cp.zeros(nelems, dtype=dtype)
 
-    return input_buf, result_buf, test_buf
+    return input_buf, result_buf, test_buf, nelems
 
 
 def main(
@@ -190,7 +192,7 @@ def main(
     collective = execution_plan.collective
 
     dtype = parse_dtype(dtype_str)
-    input_buf, result_buf, test_buf = build_bufs(
+    input_buf, result_buf, test_buf, nelem = build_bufs(
         collective,
         size,
         in_place,
@@ -212,6 +214,22 @@ def main(
     )
 
     mscclpp_group.barrier()
+    print("size= ", size, "nelem= ", nelem)
+
+    # Sentinel fill: choose something unlikely in your pattern
+    result_buf.fill(cp.float16(123.0))
+    cp.cuda.runtime.deviceSynchronize()
+
+    # Run ONE execution (no graph), then sync
+    stream = cp.cuda.Stream(non_blocking=True)
+    with stream:
+        executor_func(stream)
+    stream.synchronize()
+
+    # Count how many elements changed
+    changed = cp.count_nonzero(result_buf != cp.float16(123.0)).item()
+    print("changed elements:", changed, "out of", result_buf.size)
+
     bench_correctness(
         collective,
         input_buf,