lib/event: do not set default scheduling period during init

reactor_run() decides whether to start gather_metrics
based on non-zero scheduler period.
The default of 1 sec was set during initialization,
in scheduler_subsystem_init().

This resulted in unessecary operations each second,
even if only 'static' scheduler is used.

This patch moves setting default scheduling period to
respective schedulers.

Signed-off-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Change-Id: I953aee271a959b6314c8e83434c922dba9638de4
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/9492
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot
Reviewed-by: Konrad Sztyber <konrad.sztyber@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Shuhei Matsumoto <smatsumoto@nvidia.com>

lib/event/scheduler_static.c

@@ -15,6 +15,9 @@
 static int
 init_static(void)
 {
+	/* There is no scheduling perfomed by static scheduler,
+	 * do not set the scheduling period. */
+	spdk_scheduler_set_period(0);
 	return 0;
 }
 

module/event/subsystems/scheduler/scheduler.c

@@ -19,9 +19,6 @@ scheduler_subsystem_init(void)
 	if (spdk_scheduler_get() == NULL) {
 		rc = spdk_scheduler_set("static");
 	}
-	if (spdk_scheduler_get_period() == 0) {
-		spdk_scheduler_set_period(SPDK_SEC_TO_USEC);
-	}
 
 	spdk_subsystem_init_next(rc);
 }

module/scheduler/dynamic/scheduler_dynamic.c

@@ -244,6 +244,11 @@ init(void)
 		return -ENOMEM;
 	}
 
+	if (spdk_scheduler_get_period() == 0) {
+		/* set default scheduling period to one second */
+		spdk_scheduler_set_period(SPDK_SEC_TO_USEC);
+	}
+
 	return 0;
 }