diff --git a/run.py b/run.py
index f2cbfc6..7e5ccfc 100755
--- a/run.py
+++ b/run.py
@@ -6,44 +6,89 @@
 import subprocess
 import statistics
 import sys
+import time
 from tabulate import tabulate
 
-def run_benchmark(executable, suite, test_file, iterations, index, total, suppress_output=False):
+
+def run_benchmark(
+    executable, suite, test_file, iterations, index, total, suppress_output=False
+):
     times = []
     for i in range(iterations):
         if not suppress_output:
-            print(f"[{index}/{total}] {suite}/{test_file} (Iteration {i+1}/{iterations}, Avg: {statistics.mean(times):.3f}s)" if times else f"[{index}/{total}] {suite}/{test_file} (Iteration {i+1}/{iterations})", end="\r")
+            print(
+                f"[{index}/{total}] {suite}/{test_file} (Iteration {i + 1}/{iterations}, Avg: {statistics.mean(times):.3f}s)"
+                if times
+                else f"[{index}/{total}] {suite}/{test_file} (Iteration {i + 1}/{iterations})",
+                end="\r",
+            )
             sys.stdout.flush()
 
-        result = subprocess.run([f"time -p {executable} {suite}/{test_file}"], shell=True, stderr=subprocess.PIPE, stdout=subprocess.DEVNULL, text=True, executable="/bin/bash")
+        command = [executable, os.path.join(suite, test_file)]
+        start_time = time.perf_counter_ns()
+        result = subprocess.run(
+            command,
+            stderr=subprocess.PIPE,
+            stdout=subprocess.DEVNULL,
+            text=True,
+        )
+        end_time = time.perf_counter_ns()
         result.check_returncode()
+        elapsed_time_ns = end_time - start_time
+        elapsed_time_s = elapsed_time_ns / 1_000_000_000.0
 
-        time_output = result.stderr.split("\n")
-        real_time_line = [line for line in time_output if "real" in line][0]
-        time_taken = float(real_time_line.split(" ")[-1])
-        times.append(time_taken)
+        times.append(elapsed_time_s)
 
     mean = statistics.mean(times)
     stdev = statistics.stdev(times) if len(times) > 1 else 0
     min_time = min(times)
     max_time = max(times)
     if not suppress_output:
-        print(f"[{index}/{total}] {suite}/{test_file} completed. Mean: {mean:.3f}s ± {stdev:.3f}s, Range: {min_time:.3f}s … {max_time:.3f}s\033[K")
+        print(
+            f"[{index}/{total}] {suite}/{test_file} completed. Mean: {mean:.3f}s ± {stdev:.3f}s, Range: {min_time:.3f}s … {max_time:.3f}s\033[K"
+        )
         sys.stdout.flush()
 
     return mean, stdev, min_time, max_time, times
 
+
 def main():
     parser = argparse.ArgumentParser(description="Run JavaScript benchmarks.")
-    parser.add_argument("--executable", "-e", default="js", help="Path to the JavaScript executable.")
-    parser.add_argument("--iterations", "-i", type=int, default=3, help="Number of iterations for each test.")
-    parser.add_argument("--suites", "-s", default="all", help="Comma-separated list of suites to run.")
-    parser.add_argument("--warmups", "-w", type=int, default=0, help="Number of warm-up runs of SunSpider.")
-    parser.add_argument("--output", "-o", default="results.json", help="JSON output file name.")
+    parser.add_argument(
+        "--executable", "-e", default="js", help="Path to the JavaScript executable."
+    )
+    parser.add_argument(
+        "--iterations",
+        "-i",
+        type=int,
+        default=3,
+        help="Number of iterations for each test.",
+    )
+    parser.add_argument(
+        "--suites", "-s", default="all", help="Comma-separated list of suites to run."
+    )
+    parser.add_argument(
+        "--warmups",
+        "-w",
+        type=int,
+        default=0,
+        help="Number of warm-up runs of SunSpider.",
+    )
+    parser.add_argument(
+        "--output", "-o", default="results.json", help="JSON output file name."
+    )
     args = parser.parse_args()
 
     if args.suites == "all":
-        suites = ["SunSpider", "Kraken", "Octane", "JetStream", "JetStream3", "RegExp", "MicroBench"]
+        suites = [
+            "SunSpider",
+            "Kraken",
+            "Octane",
+            "JetStream",
+            "JetStream3",
+            "RegExp",
+            "MicroBench",
+        ]
     else:
         suites = args.suites.split(",")
 
@@ -53,7 +98,15 @@ def main():
             for test_file in sorted(os.listdir("SunSpider")):
                 if not test_file.endswith(".js"):
                     continue
-                run_benchmark(args.executable, "SunSpider", test_file, 1, 0, 0, suppress_output=True)
+                run_benchmark(
+                    args.executable,
+                    "SunSpider",
+                    test_file,
+                    1,
+                    0,
+                    0,
+                    suppress_output=True,
+                )
 
     results = {}
     table_data = []
@@ -65,21 +118,38 @@ def main():
         for test_file in sorted(os.listdir(suite)):
             if not test_file.endswith(".js"):
                 continue
-            mean, stdev, min_time, max_time, runs = run_benchmark(args.executable, suite, test_file, args.iterations, current_test, total_tests)
+            mean, stdev, min_time, max_time, runs = run_benchmark(
+                args.executable,
+                suite,
+                test_file,
+                args.iterations,
+                current_test,
+                total_tests,
+            )
             results[suite][test_file] = {
                 "mean": mean,
                 "stdev": stdev,
                 "min": min_time,
                 "max": max_time,
-                "runs": runs
+                "runs": runs,
             }
-            table_data.append([suite, test_file, f"{mean:.3f} ± {stdev:.3f}", f"{min_time:.3f} … {max_time:.3f}"])
+            table_data.append(
+                [
+                    suite,
+                    test_file,
+                    f"{mean:.3f} ± {stdev:.3f}",
+                    f"{min_time:.3f} … {max_time:.3f}",
+                ]
+            )
             current_test += 1
 
-    print(tabulate(table_data, headers=["Suite", "Test", "Mean ± σ", "Range (min … max)"]))
+    print(
+        tabulate(table_data, headers=["Suite", "Test", "Mean ± σ", "Range (min … max)"])
+    )
 
     with open(args.output, "w") as f:
         json.dump(results, f, indent=4)
 
+
 if __name__ == "__main__":
     main()