diff --git a/tools/src/h5perf/pio_perf.c b/tools/src/h5perf/pio_perf.c
index 1460772d27..26e90f8a5b 100644
--- a/tools/src/h5perf/pio_perf.c
+++ b/tools/src/h5perf/pio_perf.c
@@ -311,7 +311,7 @@ run_test_loop(struct options *opts)
 {
     parameters parms;
     int        num_procs;
-    int        doing_pio; /* if this process is doing PIO */
+    int        doing_pio = 0; /* if this process is doing parallel IO */
 
     parms.num_files     = opts->num_files;
     parms.num_dsets     = opts->num_dsets;