Точное измерение временных промежутков

Первый же example оттуда не компилится. Говорит, undefined reference to 'clock_getres'. Какой ключ подсунуть gcc?

valgrind --tool=cachegrind
kcachegrind

#ifndef __TSC_TSCMEASUREMENT_H__
#define __TSC_TSCMEASUREMENT_H__

#ifdef __cplusplus
extern "C" {
#endif

typedef struct {
	long unsigned	tsc_low,
			tsc_high,
			tsc_low1,
			tsc_high1;
} TscMeasurement;

#define rdtsc(low,high) \
     __asm__ __volatile__("rdtsc" : "=a" (low), "=d" (high))

inline void tsc_start_measurement (TscMeasurement *tm) {
	rdtsc (tm->tsc_low, tm->tsc_high);
}

inline void tsc_stop_measurement (TscMeasurement *tm) {
	rdtsc (tm->tsc_low1, tm->tsc_high1);
}

inline long long unsigned tsc_get_ticks (const TscMeasurement *tm)
{
	long long unsigned tsc, tsc1;
	tsc = (long long unsigned) tm->tsc_high << 32 |
		((long long unsigned) tm->tsc_low & 0xffffffff);
	tsc1 = (long long unsigned) tm->tsc_high1 << 32 |
		((long long unsigned) tm->tsc_low1 & 0xffffffff);
	return tsc1 - tsc;
}

#ifdef __cplusplus
}
#endif

#endif /*__TSC_TSCMEASUREMENT_H__*/

#define rdtsc(low,high) \ __asm__ __volatile__("rdtsc" : "=a" (low), "=d" (high))

можно

#define rdtsc(tsc) \ __asm__ __volatile___( "rdtsc" : "=A" (tsc) );

дальше сами переделывайте

> #define rdtsc(tsc) \ __asm__ __volatile___( "rdtsc" : "=A" (tsc) );

точно, спасибо!