diff --git a/idletime.h b/idletime.h
new file mode 100644
index 0000000..acb8407
--- /dev/null
+++ b/idletime.h
@@ -0,0 +1,57 @@
+#ifndef FIO_IDLETIME_H
+#define FIO_IDLETIME_H
+
+#include "fio.h"
+
+#define CALIBRATE_RUNS  10
+#define CALIBRATE_SCALE 1000
+#define MAX_CPU_STR_LEN 32
+
+enum {
+	IDLE_PROF_OPT_NONE,
+	IDLE_PROF_OPT_CALI,                /* calibration only */
+	IDLE_PROF_OPT_SYSTEM,
+	IDLE_PROF_OPT_PERCPU
+};
+
+enum {
+	 IDLE_PROF_STATUS_OK,
+	 IDLE_PROF_STATUS_CALI_STOP,
+	 IDLE_PROF_STATUS_PROF_STOP,
+	 IDLE_PROF_STATUS_ABORT
+};
+
+struct idle_prof_thread {
+	pthread_t thread;
+	int cpu;
+	int state;
+	struct timeval tps;
+	struct timeval tpe;
+	double cali_time; /* microseconds to finish a unit wrok */
+	double loops;
+	double idleness;
+	unsigned char *data;             /* bytes to be touched */
+	pthread_cond_t  cond;
+	pthread_mutex_t init_lock;
+	pthread_mutex_t start_lock;
+};
+
+struct idle_prof_common {
+	struct idle_prof_thread *ipts;
+	int nr_cpus;
+	int status;
+	int opt;
+	double cali_mean;
+	double cali_stddev;
+	void *buf;    /* single data allocation for all threads */
+};
+
+extern int fio_idle_prof_parse_opt(const char *);
+
+extern void fio_idle_prof_init(void);
+extern void fio_idle_prof_start(void);
+extern void fio_idle_prof_stop(void);
+
+extern void show_idle_prof_stats(int, struct json_object *);
+
+#endif