diff --git a/scripts/perf/nvmf/run_nvmf.py b/scripts/perf/nvmf/run_nvmf.py
index 5e893a1f8..69f432eb8 100755
--- a/scripts/perf/nvmf/run_nvmf.py
+++ b/scripts/perf/nvmf/run_nvmf.py
@@ -589,7 +589,7 @@ class Target(Server):
             fh.write(out)
         sar_cpu_usage = cpu_number * 100 - sar_idle_sum
         with open(os.path.join(results_dir, sar_file_name), "a") as f:
-            f.write("Total CPU used: %s", % sar_cpu_usage)
+            f.write("Total CPU used: ".join(sar_cpu_usage))
 
     def measure_pcm_memory(self, results_dir, pcm_file_name):
         time.sleep(self.pcm_delay)