From 87a92d995fe1a13ef96c031cbc71f69584119eec Mon Sep 17 00:00:00 2001
From: ligd <liguiding1@xiaomi.com>
Date: Fri, 10 Feb 2023 22:54:55 +0800
Subject: [PATCH] sim: fix nuttx consumes much CPU time

Signed-off-by: ligd <liguiding1@xiaomi.com>
---
 arch/sim/src/sim/sim_oneshot.c | 38 +++++++++++++++++++++++-----------
 1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/arch/sim/src/sim/sim_oneshot.c b/arch/sim/src/sim/sim_oneshot.c
index 113843fefc..df89fd8ae3 100644
--- a/arch/sim/src/sim/sim_oneshot.c
+++ b/arch/sim/src/sim/sim_oneshot.c
@@ -122,6 +122,20 @@ static inline void sim_timer_current(struct timespec *ts)
   ts->tv_nsec = nsec;
 }
 
+/****************************************************************************
+ * Name: sim_reset_alarm
+ *
+ * Description:
+ *   Reset the alarm to MAX
+ *
+ ****************************************************************************/
+
+static inline void sim_reset_alarm(struct timespec *alarm)
+{
+  alarm->tv_sec  = UINT_MAX;
+  alarm->tv_nsec = NSEC_PER_SEC - 1;
+}
+
 /****************************************************************************
  * Name: sim_update_hosttimer
  *
@@ -217,16 +231,18 @@ static void sim_process_tick(sq_entry_t *entry)
 
   DEBUGASSERT(priv != NULL);
 
+  struct timespec current;
+
+  sim_timer_current(&current);
+  if (clock_timespec_compare(&priv->alarm, &current) > 0)
+    {
+      return; /* Alarm doesn't expire yet */
+    }
+
+  sim_reset_alarm(&priv->alarm);
+
   if (priv->callback)
     {
-      struct timespec current;
-
-      sim_timer_current(&current);
-      if (clock_timespec_compare(&priv->alarm, &current) > 0)
-        {
-          return; /* Alarm doesn't expire yet */
-        }
-
       /* Sample and nullify BEFORE executing callback (in case the callback
        * restarts the oneshot).
        */
@@ -355,9 +371,7 @@ static int sim_cancel(struct oneshot_lowerhalf_s *lower,
   sim_timer_current(&current);
   clock_timespec_subtract(&priv->alarm, &current, ts);
 
-  priv->alarm.tv_sec  = UINT_MAX;
-  priv->alarm.tv_nsec = NSEC_PER_SEC - 1;
-
+  sim_reset_alarm(&priv->alarm);
   sim_update_hosttimer();
 
   priv->callback = NULL;
@@ -505,7 +519,6 @@ void up_timer_initialize(void)
 
 void sim_timer_update(void)
 {
-#ifdef CONFIG_SIM_WALLTIME_SLEEP
   static uint64_t until;
 
   /* Wait a bit so that the timing is close to the correct rate. */
@@ -513,6 +526,7 @@ void sim_timer_update(void)
   until += NSEC_PER_TICK;
   host_sleepuntil(until);
 
+#ifdef CONFIG_SIM_WALLTIME_SLEEP
   sim_timer_update_internal();
 #endif
 }