fix flent

tools/network_timing_benchmark.py

@@ -810,8 +810,8 @@ def run_flent(args: argparse.Namespace, out_dir: Path) -> list[dict[str, Any]]:
 
     results: list[dict[str, Any]] = []
     for test_name in args.flent_tests:
-        data_file = out_dir / f"flent_{safe_name(test_name)}.flent.gz"
         raw_name = f"flent_{safe_name(test_name)}.txt"
+        existing_data_files = set(out_dir.glob("*.flent.gz"))
         command = [
             "flent",
             test_name,
@@ -821,8 +821,8 @@ def run_flent(args: argparse.Namespace, out_dir: Path) -> list[dict[str, Any]]:
             args.target,
             "-t",
             f"{args.label}-{test_name}",
-            "-o",
-            str(data_file),
+            "-D",
+            str(out_dir),
         ]
         result, meta = run_command(
             command,
@@ -838,13 +838,17 @@ def run_flent(args: argparse.Namespace, out_dir: Path) -> list[dict[str, Any]]:
                 "On Ubuntu, install python3-setuptools or run Flent from a virtual environment "
                 "with setuptools installed."
             )
-        data_file_exists = data_file.is_file()
+        created_data_files = sorted(
+            set(out_dir.glob("*.flent.gz")) - existing_data_files,
+            key=lambda path: path.stat().st_mtime,
+        )
+        data_file = created_data_files[-1] if created_data_files else None
         results.append(
             {
                 "type": "flent",
                 "test": test_name,
-                "data_file": str(data_file),
-                "data_file_exists": data_file_exists,
+                "data_file": str(data_file) if data_file is not None else None,
+                "data_file_exists": data_file is not None and data_file.is_file(),
                 "meta": meta,
                 "error": error,
             }