Change in libosmocore[master]: stats: Change timer to timerfd to make it a true interval timer.

[ipse]

ipse has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmocore/+/18141 )


Change subject: stats: Change timer to timerfd to make it a true interval timer.
......................................................................

stats: Change timer to timerfd to make it a true interval timer.

Previously the interval between stats flushes would slowly increase
which would lead to reporting time jitter and confuse a timescale
database.

Change-Id: I23d8b5157ef8a9833ba16a81d9b28a126f303c30
---
M src/stats.c
1 file changed, 32 insertions(+), 7 deletions(-)



  git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/41/18141/1

diff --git a/src/stats.c b/src/stats.c
index 5954167..8cccf67 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -85,7 +85,7 @@
 #include <osmocom/core/logging.h>
 #include <osmocom/core/rate_ctr.h>
 #include <osmocom/core/stat_item.h>
-#include <osmocom/core/timer.h>
+#include <osmocom/core/select.h>
 #include <osmocom/core/counter.h>
 #include <osmocom/core/msgb.h>
 
@@ -102,7 +102,7 @@
 };
 struct osmo_stats_config *osmo_stats_config = &s_stats_config;
 
-static struct osmo_timer_list osmo_stats_timer;
+static struct osmo_fd osmo_stats_timer = {.fd=-1};
 
 static int osmo_stats_reporter_log_send_counter(struct osmo_stats_reporter *srep,
 	const struct rate_ctr_group *ctrg,
@@ -140,23 +140,48 @@
 	return rc;
 }
 
-static void osmo_stats_timer_cb(void *data)
+static int osmo_stats_timer_cb(struct osmo_fd *ofd, unsigned int what)
 {
-	int interval = osmo_stats_config->interval;
+	uint64_t expire_count;
+	int rc;
+
+	/* check that the timer has actually expired */
+	if (!(what & BSC_FD_READ))
+		return 0;
+
+	/* read from timerfd: number of expirations of periodic timer */
+	rc = read(ofd->fd, (void *) &expire_count, sizeof(expire_count));
+	if (rc < 0 && errno == EAGAIN)
+		return 0;
+	OSMO_ASSERT(rc == sizeof(expire_count));
 
 	if (!llist_empty(&osmo_stats_reporter_list))
 		osmo_stats_report();
 
-	osmo_timer_schedule(&osmo_stats_timer, interval, 0);
+	return 0;
 }
 
 static int start_timer()
 {
+	int rc;
+	int interval = osmo_stats_config->interval;
+
 	if (!is_initialised)
 		return -ESRCH;
 
-	osmo_timer_setup(&osmo_stats_timer, osmo_stats_timer_cb, NULL);
-	osmo_timer_schedule(&osmo_stats_timer, 0, 1);
+	struct timespec ts_first = {.tv_sec=0, .tv_nsec=1000};
+	struct timespec ts_interval = {.tv_sec=interval, .tv_nsec=0};
+
+	rc = osmo_timerfd_setup(&osmo_stats_timer, osmo_stats_timer_cb, NULL);
+	if (rc < 0)
+		LOGP(DLSTATS, LOGL_ERROR, "Failed to setup the timer with error code %d (fd=%d)\n",
+		     rc, osmo_stats_timer.fd);
+	rc = osmo_timerfd_schedule(&osmo_stats_timer, &ts_first, &ts_interval);
+	if (rc < 0)
+		LOGP(DLSTATS, LOGL_ERROR, "Failed to schedule the timer with error code %d (fd=%d, interval %d sec)\n",
+		     rc, osmo_stats_timer.fd, interval);
+
+	LOGP(DLSTATS, LOGL_INFO, "Stats timer started with interval %d sec\n", interval);
 
 	return 0;
 }

-- 
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Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: I23d8b5157ef8a9833ba16a81d9b28a126f303c30
Gerrit-Change-Number: 18141
Gerrit-PatchSet: 1
Gerrit-Owner: ipse <Alexander.Chemeris at gmail.com>
Gerrit-MessageType: newchange
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