From: Michael Tremer <michael.tremer@ipfire.org>
Date: Mon, 6 Oct 2025 17:03:52 +0000 (+0000)
Subject: source: Stagger sources to avoid load peaks
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=360fce41179c347ee12f0b68760dc8de4198c2c5;p=telemetry.git

source: Stagger sources to avoid load peaks

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/daemon/source.c b/src/daemon/source.c
index cd07503..fd53b31 100644
--- a/src/daemon/source.c
+++ b/src/daemon/source.c
@@ -38,6 +38,11 @@
 #include "time.h"
 #include "util.h"
 
+// When the daemon starts up, we should not collect everything straight away to
+// avoid any usage peaks. Therefore we will stagger all sources randomly across
+// N seconds.
+#define STAGGER	60
+
 #define STEPSIZE 60 // seconds
 
 // Interval after which the heartbeat function is being called again
@@ -326,15 +331,19 @@ static int collecty_source_heartbeat(sd_event_source* source, uint64_t usec, voi
 }
 
 static int collecty_source_register_heartbeat(collecty_source* self) {
+	uint64_t heartbeat = 0;
 	int r;
 
 	// No need to do this if we don't have a collect method
 	if (!self->impl->collect)
 		return 0;
 
+	// To avoid any load peaks, stagger sources
+	heartbeat = SEC_TO_USEC(rand() % STAGGER);
+
 	// Call the heartbeat function immediately
 	r = sd_event_add_time_relative(self->loop, &self->events.heartbeat,
-			CLOCK_MONOTONIC, 0, 0, collecty_source_heartbeat, self);
+			CLOCK_MONOTONIC, heartbeat, 0, collecty_source_heartbeat, self);
 	if (r < 0) {
 		ERROR(self->ctx, "Failed to register the heartbeat timer: %s\n", strerror(-r));
 		return r;