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-rw-r--r--erts/emulator/beam/erl_time_sup.c76
1 files changed, 74 insertions, 2 deletions
diff --git a/erts/emulator/beam/erl_time_sup.c b/erts/emulator/beam/erl_time_sup.c
index 668dbb5daa..6509c6a805 100644
--- a/erts/emulator/beam/erl_time_sup.c
+++ b/erts/emulator/beam/erl_time_sup.c
@@ -1749,7 +1749,7 @@ erts_get_monotonic_time(ErtsSchedulerData *esdp)
{
ErtsMonotonicTime mtime = time_sup.r.o.get_time();
update_last_mtime(esdp, mtime);
- return mtime;
+ return mtime;
}
ErtsMonotonicTime
@@ -2435,9 +2435,81 @@ BIF_RETTYPE os_system_time_0(BIF_ALIST_0)
BIF_RET(make_time_val(BIF_P, stime));
}
-BIF_RETTYPE os_system_time_1(BIF_ALIST_0)
+BIF_RETTYPE os_system_time_1(BIF_ALIST_1)
{
ErtsSystemTime stime = erts_os_system_time();
BIF_RET(time_unit_conversion(BIF_P, BIF_ARG_1, stime, 0));
}
+BIF_RETTYPE
+os_perf_counter_0(BIF_ALIST_0)
+{
+ ErtsSysHrTime pcounter;
+ sys_perf_counter(&pcounter);
+ BIF_RET(make_time_val(BIF_P, pcounter));
+}
+
+BIF_RETTYPE erts_internal_perf_counter_unit_0(BIF_ALIST_0)
+{
+ BIF_RET(make_time_val(BIF_P, SYS_PERF_COUNTER_UNIT));
+}
+
+/* What resolution to spin to in micro seconds */
+#define RESOLUTION 100
+/* How many iterations to spin */
+#define ITERATIONS 1
+/* How many significant figures to round to */
+#define SIGFIGS 3
+
+static ErtsSysHrTime perf_counter_unit = 0;
+
+static ErtsSysHrTime erts_calculate_perf_counter_unit(void);
+static ErtsSysHrTime erts_calculate_perf_counter_unit() {
+ int i;
+ ErtsSysHrTime pre, post;
+ double value = 0;
+ double round_factor;
+#if defined(HAVE_GETHRTIME) && defined(GETHRTIME_WITH_CLOCK_GETTIME)
+ struct timespec basetime,comparetime;
+#define __GETTIME(arg) clock_gettime(CLOCK_MONOTONIC,arg)
+#define __GETUSEC(arg) (arg.tv_nsec / 1000)
+#else
+ SysTimeval basetime,comparetime;
+#define __GETTIME(arg) sys_gettimeofday(arg)
+#define __GETUSEC(arg) arg.tv_usec
+#endif
+
+ for (i = 0; i < ITERATIONS; i++) {
+ /* Make sure usec just flipped over at current resolution */
+ __GETTIME(&basetime);
+ do {
+ __GETTIME(&comparetime);
+ } while ((__GETUSEC(basetime) / RESOLUTION) == (__GETUSEC(comparetime) / RESOLUTION));
+
+ sys_perf_counter(&pre);
+
+ __GETTIME(&basetime);
+ do {
+ __GETTIME(&comparetime);
+ } while ((__GETUSEC(basetime) / RESOLUTION) == (__GETUSEC(comparetime) / RESOLUTION));
+
+ sys_perf_counter(&post);
+
+ value += post - pre;
+ }
+ /* After this value is ticks per us */
+ value /= (RESOLUTION*ITERATIONS);
+
+ /* We round to 3 significant figures */
+ round_factor = pow(10.0, SIGFIGS - ceil(log10(value)));
+ value = ((ErtsSysHrTime)(value * round_factor + 0.5)) / round_factor;
+
+ /* convert to ticks per second */
+ return 1000000 * value;
+}
+
+ErtsSysHrTime erts_perf_counter_unit() {
+ if (perf_counter_unit == 0)
+ perf_counter_unit = erts_calculate_perf_counter_unit();
+ return perf_counter_unit;
+}