introduce heartbeat API using monotonic clock
Signed-off-by: Rémi Lefèvre <remi.lefevre@parrot.com>
Rémi Lefèvre committed
Dec 13, 2016 at 16:12 UTC
c032b7be6773ba76c0560bfed83d2b0b86b267d6
2 files changed
+49
-2
src/clocks.c
+35
@@ -71,3 +71,38 @@ inline usec_t dt_usec(struct timeval *now, struct timeval *old) {
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usec_t ts2 = timeval_usec(old);
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return (ts1 > ts2) ? (ts1 - ts2) : (ts2 - ts1);
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}
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+
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+inline void heartbeat_init(heartbeat_t *hb)
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+{
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+ *hb = 0ULL;
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+}
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+
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+usec_t heartbeat_next(heartbeat_t *hb, usec_t tick)
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+{
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+ heartbeat_t now = now_monotonic_usec();
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+ usec_t next = now - (now % tick) + tick;
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+
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+ while(now < next) {
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+ sleep_usec(next - now);
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+ now = now_monotonic_usec();
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+ }
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+
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+ if(likely(*hb != 0ULL)) {
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+ usec_t dt = now - *hb;
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+ *hb = now;
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+ if(unlikely(dt / tick > 1))
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+ error("heartbeat missed between %llu usec and %llu usec", *hb, now);
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+ return dt;
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+ }
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+ else {
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+ *hb = now;
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+ return 0ULL;
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+ }
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+}
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+
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+inline usec_t heartbeat_dt_usec(heartbeat_t *hb)
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+{
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+ if(!*hb)
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+ return 0ULL;
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+ return now_monotonic_usec() - *hb;
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+}
src/clocks.h
+14
-2
@@ -12,6 +12,10 @@ struct timespec {
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typedef int clockid_t;
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#endif
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+typedef unsigned long long usec_t;
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+
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+typedef usec_t heartbeat_t;
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+
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#ifndef HAVE_CLOCK_GETTIME
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int clock_gettime(clockid_t clk_id, struct timespec *ts);
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#endif
@@ -35,8 +39,6 @@ int clock_gettime(clockid_t clk_id, struct timespec *ts);
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#endif
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#endif
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-typedef unsigned long long usec_t;
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-
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#define NSEC_PER_SEC 1000000000ULL
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#define NSEC_PER_MSEC 1000000ULL
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#define NSEC_PER_USEC 1000ULL
@@ -89,4 +91,14 @@ extern usec_t now_boottime_usec(void);
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extern usec_t timeval_usec(struct timeval *ts);
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extern usec_t dt_usec(struct timeval *now, struct timeval *old);
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+extern void heartbeat_init(heartbeat_t *hb);
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+
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+/* Sleeps until next multiple of tick using monotonic clock.
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+ * Returns elapsed time in microseconds since previous heartbeat
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+ */
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+extern usec_t heartbeat_next(heartbeat_t *hb, usec_t tick);
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+
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+/* Returns elapsed time in microseconds since last heartbeat */
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+extern usec_t heartbeat_dt_usec(heartbeat_t *hb);
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+
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#endif /* NETDATA_CLOCKS_H */