* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
-#ifndef UST_CLOCK_H
-#define UST_CLOCK_H
+#ifndef _UST_CLOCK_H
+#define _UST_CLOCK_H
+#include <time.h>
#include <sys/time.h>
#include <ust/kcompat/kcompat.h>
- gettimeofday() clock
Microbenchmarks on Linux 2.6.30 on Core2 Duo 3GHz (functions are inlined):
- Calls (100000000) to tsc(): 4004035641 cycles or 40 cycles/call
- Calls (100000000) to gettimeofday(): 9723158352 cycles or 97 cycles/call
+ Calls (100000000) to tsc(): 4004035641 cycles or 40 cycles/call
+ Calls (100000000) to gettimeofday(): 9723158352 cycles or 97 cycles/call
For merging traces with the kernel, a time source compatible with that of
the kernel is necessary.
+ Instead of gettimeofday(), we are now using clock_gettime for better
+ precision and monotonicity.
*/
-#define TRACE_CLOCK_GENERIC
-#ifdef TRACE_CLOCK_GENERIC
+/* Only available for x86 arch */
+#define CLOCK_TRACE_FREQ 14
+#define CLOCK_TRACE 15
+union lttng_timespec {
+ struct timespec ts;
+ u64 lttng_ts;
+};
+
+extern int ust_clock_source;
+
+/* Choosing correct trace clock */
static __inline__ u64 trace_clock_read64(void)
{
- struct timeval tv;
+ struct timespec ts;
u64 retval;
-
- gettimeofday(&tv, NULL);
- retval = tv.tv_sec;
- retval *= 1000000;
- retval += tv.tv_usec;
+ union lttng_timespec *lts = (union lttng_timespec *) &ts;
+
+ clock_gettime(ust_clock_source, &ts);
+ /*
+ * Clock source can change when loading the binary (tracectl.c)
+ * so we must check if the clock source has changed before
+ * returning the correct value
+ */
+ if (likely(ust_clock_source == CLOCK_TRACE)) {
+ retval = lts->lttng_ts;
+ } else { /* CLOCK_MONOTONIC */
+ retval = ts.tv_sec;
+ retval *= 1000000000;
+ retval += ts.tv_nsec;
+ }
return retval;
}
-#else
-
-#if __i386 || __x86_64
-
-/* WARNING: Make sure to set frequency and scaling functions that will not
- * result in lttv timestamps (sec.nsec) with seconds greater than 2**32-1.
- */
-static __inline__ u64 trace_clock_read64(void)
-{
- uint32_t low;
- uint32_t high;
- uint64_t retval;
- __asm__ volatile ("rdtsc\n" : "=a" (low), "=d" (high));
-
- retval = high;
- retval <<= 32;
- return retval | low;
-}
-
-#endif /* __i386 || __x86_64 */
-
-#ifdef __PPC__
-
-static __inline__ u64 trace_clock_read64(void)
+#if __i386__ || __x86_64__
+static __inline__ u64 trace_clock_frequency(void)
{
- unsigned long tb_l;
- unsigned long tb_h;
- unsigned long tb_h2;
- u64 tb;
-
- __asm__ (
- "1:\n\t"
- "mftbu %[rhigh]\n\t"
- "mftb %[rlow]\n\t"
- "mftbu %[rhigh2]\n\t"
- "cmpw %[rhigh],%[rhigh2]\n\t"
- "bne 1b\n\t"
- : [rhigh] "=r" (tb_h), [rhigh2] "=r" (tb_h2), [rlow] "=r" (tb_l));
-
- tb = tb_h;
- tb <<= 32;
- tb |= tb_l;
-
- return tb;
+ struct timespec ts;
+ union lttng_timespec *lts = (union lttng_timespec *) &ts;
+
+ if (likely(ust_clock_source == CLOCK_TRACE)) {
+ clock_gettime(CLOCK_TRACE_FREQ, &ts);
+ return lts->lttng_ts;
+ }
+ return 1000000000LL;
}
-
-#endif /* __PPC__ */
-
-#endif /* ! UST_TRACE_CLOCK_GENERIC */
-
+#else /* #if __i386__ || __x86_64__ */
static __inline__ u64 trace_clock_frequency(void)
{
- return 1000000LL;
+ return 1000000000LL;
}
+#endif /* #else #if __i386__ || __x86_64__ */
static __inline__ u32 trace_clock_freq_scale(void)
{
return 1;
}
-#endif /* UST_CLOCK_H */
+#endif /* _UST_CLOCK_H */