1 files changed, 34 insertions, 0 deletions

diff --git a/nacl/cpucycles/monotonic.c b/nacl/cpucycles/monotonic.c
new file mode 100644
index 00000000..412a44fb
--- /dev/null
+++ b/nacl/cpucycles/monotonic.c
@@ -0,0 +1,34 @@
+#include <time.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+
+static double cpufrequency = 0;
+
+static void init(void)
+{
+  long result = 0; size_t resultlen = sizeof(long);
+  sysctlbyname("machdep.tsc_freq",&result,&resultlen,0,0);
+  cpufrequency = result;
+}
+
+long long cpucycles_monotonic(void)
+{
+  double result;
+  struct timespec t;
+  if (!cpufrequency) init();
+  clock_gettime(CLOCK_MONOTONIC,&t);
+  result = t.tv_nsec;
+  result *= 0.000000001;
+  result += (double) t.tv_sec;
+  result *= cpufrequency;
+  return result;
+}
+
+long long cpucycles_monotonic_persecond(void)
+{
+  if (!cpufrequency) init();
+  return cpufrequency;
+}