Use CLOCK_MONOTONIC if we can

[fio.git] / gettime.c

diff --git a/gettime.c b/gettime.c
index 08d2d2b3b1205a56543ec6aef00e52b37711d622..15356b1b9227c2b92f7676aae124664647f0e5d1 100644 (file)
--- a/gettime.c
+++ b/gettime.c
@@ -5,15 +5,18 @@
 #include <unistd.h>
 #include <math.h>
 #include <sys/time.h>
+#include <time.h>
 
 #include "fio.h"
 #include "smalloc.h"
 
 #include "hash.h"
 
+#ifdef ARCH_HAVE_CPU_CLOCK
 static unsigned long cycles_per_usec;
-static struct timeval last_tv;
 static unsigned long last_cycles;
+#endif
+static struct timeval last_tv;
 static int last_tv_valid;
 
 static struct timeval *fio_tv;
@@ -137,7 +140,11 @@ void fio_gettime(struct timeval *tp, void fio_unused *caller)
        case CS_CGETTIME: {
                struct timespec ts;
 
+#ifdef FIO_HAVE_CLOCK_MONOTONIC
+               if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
+#else
                if (clock_gettime(CLOCK_REALTIME, &ts) < 0) {
+#endif
                        log_err("fio: clock_gettime fails\n");
                        assert(0);
                }
@@ -183,6 +190,7 @@ void fio_gettime(struct timeval *tp, void fio_unused *caller)
        memcpy(&last_tv, tp, sizeof(*tp));
 }
 
+#ifdef ARCH_HAVE_CPU_CLOCK
 static unsigned long get_cycles_per_usec(void)
 {
        struct timeval s, e;
@@ -204,14 +212,12 @@ static unsigned long get_cycles_per_usec(void)
        return c_e - c_s;
 }
 
-void fio_clock_init(void)
+static void calibrate_cpu_clock(void)
 {
        double delta, mean, S;
        unsigned long avg, cycles[10];
        int i, samples;
 
-       last_tv_valid = 0;
-
        cycles[0] = get_cycles_per_usec();
        S = delta = mean = 0.0;
        for (i = 0; i < 10; i++) {
@@ -229,7 +235,7 @@ void fio_clock_init(void)
        for (i = 0; i < 10; i++) {
                double this = cycles[i];
 
-               if ((max(this, mean) - min(this, mean)) > S)
+               if ((fmax(this, mean) - fmin(this, mean)) > S)
                        continue;
                samples++;
                avg += this;
@@ -246,6 +252,18 @@ void fio_clock_init(void)
        dprint(FD_TIME, "mean=%f, S=%f\n", mean, S);
 
        cycles_per_usec = avg;
+
+}
+#else
+static void calibrate_cpu_clock(void)
+{
+}
+#endif
+
+void fio_clock_init(void)
+{
+       last_tv_valid = 0;
+       calibrate_cpu_clock();
 }
 
 void fio_gtod_init(void)