kernel: use timing functions to gather thread runtime stats

This uses the timing functions to gather execution cycles of
threads. This provides greater details if arch/SoC/board
uses timer with higher resolution.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>

include/kernel.h

@@ -19,6 +19,10 @@
 #include <stdbool.h>
 #include <toolchain.h>
 
+#ifdef CONFIG_THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS
+#include <timing/timing.h>
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -283,14 +287,22 @@ struct z_poller {
 #ifdef CONFIG_THREAD_RUNTIME_STATS
 struct k_thread_runtime_stats {
 	/* Thread execution cycles */
+#ifdef CONFIG_THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS
+	timing_t execution_cycles;
+#else
 	uint64_t execution_cycles;
+#endif
 };
 
 typedef struct k_thread_runtime_stats k_thread_runtime_stats_t;
 
 struct _thread_runtime_stats {
 	/* Timestamp when last switched in */
+#ifdef CONFIG_THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS
+	timing_t last_switched_in;
+#else
 	uint32_t last_switched_in;
+#endif
 
 	k_thread_runtime_stats_t stats;
 };

kernel/Kconfig

@@ -355,7 +355,7 @@ config THREAD_MAX_NAME_LEN
 config INSTRUMENT_THREAD_SWITCHING
 	bool
 
-config THREAD_RUNTIME_STATS
+menuconfig THREAD_RUNTIME_STATS
 	bool "Thread runtime statistics"
 	select INSTRUMENT_THREAD_SWITCHING
 	help
@@ -364,6 +364,19 @@ config THREAD_RUNTIME_STATS
 	  For example:
 	    - Thread total execution cycles
 
+if THREAD_RUNTIME_STATS
+
+config THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS
+	bool "Use timing functions to gather statistics"
+	select TIMING_FUNCTIONS
+	help
+	  Use timing functions to gather thread runtime statistics.
+
+	  Note that timing functions may use a different timer than
+	  the default timer for OS timekeeping.
+
+endif # THREAD_RUNTIME_STATS
+
 endmenu
 
 menu "Work Queue Options"

kernel/init.c

@@ -480,6 +480,11 @@ FUNC_NORETURN void z_cstart(void)
 	__stack_chk_guard <<= 8;
 #endif	/* CONFIG_STACK_CANARIES */
 
+#ifdef CONFIG_THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS
+	timing_init();
+	timing_start();
+#endif
+
 #ifdef CONFIG_MULTITHREADING
 	switch_to_main_thread(prepare_multithreading());
 #else

kernel/thread.c

@@ -1036,14 +1036,24 @@ void z_thread_mark_switched_in(void)
 	struct k_thread *thread;
 
 	thread = k_current_get();
+#ifdef CONFIG_THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS
+	thread->rt_stats.last_switched_in = timing_counter_get();
+#else
 	thread->rt_stats.last_switched_in = k_cycle_get_32();
+#endif /* CONFIG_THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS */
+
 #endif /* CONFIG_THREAD_RUNTIME_STATS */
 }
 
 void z_thread_mark_switched_out(void)
 {
 #ifdef CONFIG_THREAD_RUNTIME_STATS
+#ifdef CONFIG_THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS
+	timing_t now;
+#else
 	uint32_t now;
+#endif /* CONFIG_THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS */
+
 	uint64_t diff;
 	struct k_thread *thread;
 
@@ -1059,10 +1069,16 @@ void z_thread_mark_switched_out(void)
 		return;
 	}
 
+#ifdef CONFIG_THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS
+	now = timing_counter_get();
+	diff = timing_cycles_get(&thread->rt_stats.last_switched_in, &now);
+#else
 	now = k_cycle_get_32();
 	diff = (uint64_t)now - thread->rt_stats.last_switched_in;
-	thread->rt_stats.stats.execution_cycles += diff;
 	thread->rt_stats.last_switched_in = 0;
+#endif /* CONFIG_THREAD_RUNTIME_STATS_USE_TIMING_FUNCTIONS */
+
+	thread->rt_stats.stats.execution_cycles += diff;
 
 	threads_runtime_stats.execution_cycles += diff;
 #endif /* CONFIG_THREAD_RUNTIME_STATS */