From 66a07bbd48dfb64a2bc819b937413d47473aed77 Mon Sep 17 00:00:00 2001
From: Allan Stephens <allan.stephens@windriver.com>
Date: Fri, 18 Nov 2016 15:32:13 -0500
Subject: [PATCH] kernel: Minor optimization to kernel event logger
 timestamping

Rewrites the timestamping logic to always generate timestamps
via a function pointer that is initialized to sys_cycle_get_32(),
but can be changed to point to a user-supplied function. This
eliminates the need for an if/then/else construct in every place
that a timestamp is generated.

Change-Id: Id11f8c41b193a93cece16565978a525056010f0e
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
---
 include/misc/kernel_event_logger.h   | 23 ++++++++---------------
 kernel/unified/kernel_event_logger.c | 16 ++++++++++------
 2 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/include/misc/kernel_event_logger.h b/include/misc/kernel_event_logger.h
index 686e8e2b1ae..764aa41d408 100644
--- a/include/misc/kernel_event_logger.h
+++ b/include/misc/kernel_event_logger.h
@@ -57,8 +57,6 @@ static inline void _sys_k_event_logger_interrupt(void) {};
  * @{
  */
 
-#ifdef CONFIG_KERNEL_EVENT_LOGGER_CUSTOM_TIMESTAMP
-
 /**
  * @typedef sys_k_timer_func_t
  * @brief Event timestamp generator function type.
@@ -74,15 +72,11 @@ typedef uint32_t (*sys_k_timer_func_t)(void);
  * @cond INTERNAL_HIDDEN
  */
 
-extern sys_k_timer_func_t _sys_k_timer_func;
-
-static inline uint32_t _sys_k_get_time(void)
-{
-	if (_sys_k_timer_func)
-		return _sys_k_timer_func();
-	else
-		return sys_cycle_get_32();
-}
+#ifdef CONFIG_KERNEL_EVENT_LOGGER_CUSTOM_TIMESTAMP
+extern sys_k_timer_func_t _sys_k_get_time;
+#else
+#define _sys_k_get_time sys_cycle_get_32
+#endif /* CONFIG_KERNEL_EVENT_LOGGER_CUSTOM_TIMESTAMP */
 
 /**
  * INTERNAL_HIDDEN @endcond
@@ -108,11 +102,10 @@ static inline uint32_t _sys_k_get_time(void)
  *
  * @return N/A
  */
-void sys_k_event_logger_set_timer(sys_k_timer_func_t func);
-#else
-static inline uint32_t _sys_k_get_time(void)
+#ifdef CONFIG_KERNEL_EVENT_LOGGER_CUSTOM_TIMESTAMP
+static inline void sys_k_event_logger_set_timer(sys_k_timer_func_t func)
 {
-	return sys_cycle_get_32();
+	_sys_k_get_time = func;
 }
 #endif /* CONFIG_KERNEL_EVENT_LOGGER_CUSTOM_TIMESTAMP */
 
diff --git a/kernel/unified/kernel_event_logger.c b/kernel/unified/kernel_event_logger.c
index a747e229ebf..9986f375907 100644
--- a/kernel/unified/kernel_event_logger.c
+++ b/kernel/unified/kernel_event_logger.c
@@ -63,12 +63,16 @@ SYS_INIT(_sys_k_event_logger_init,
 		POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
 
 #ifdef CONFIG_KERNEL_EVENT_LOGGER_CUSTOM_TIMESTAMP
-sys_k_timer_func_t _sys_k_timer_func;
-void sys_k_event_logger_set_timer(sys_k_timer_func_t func)
-{
-	_sys_k_timer_func = func;
-}
-#endif
+/*
+ * _sys_k_get_time()
+ *
+ * This function pointer can be invoked to generate an event timestamp.
+ * By default it uses the kernel's hardware clock, but can be changed
+ * to point to an application-defined routine.
+ *
+ */
+sys_k_timer_func_t _sys_k_get_time = sys_cycle_get_32;
+#endif /* CONFIG_KERNEL_EVENT_LOGGER_CUSTOM_TIMESTAMP */
 
 void sys_k_event_logger_put_timed(uint16_t event_id)
 {