sched/hrtimer: Only enable SMP related logic when in SMP mode

 Improve hrtimer to only enable SMP related logic when in SMP mode to
 improve performance in non-SMP mode

Signed-off-by: Chengdong Wang <[email protected]>

Author: wangchdo

boards/risc-v/qemu-rv/rv-virt/configs/smp64/defconfig

@@ -69,7 +69,6 @@ CONFIG_NSH_BUILTIN_APPS=y
 CONFIG_NSH_FILEIOSIZE=64
 CONFIG_RAM_SIZE=33554432
 CONFIG_RAM_START=0x80000000
-CONFIG_RR_INTERVAL=200
 CONFIG_SCHED_WAITPID=y
 CONFIG_SERIAL_UART_ARCH_MMIO=y
 CONFIG_SMP=y
@@ -82,3 +81,5 @@ CONFIG_SYSTEM_NSH_STACKSIZE=3072
 CONFIG_TESTING_OSTEST=y
 CONFIG_TESTING_SMP=y
 CONFIG_USEC_PER_TICK=1000
+CONFIG_HRTIMER=y
+CONFIG_EXAMPLES_HELLO=y

include/nuttx/hrtimer.h

@@ -102,7 +102,9 @@ struct hrtimer_s
   hrtimer_cb func;             /* Expiration callback function */
   FAR void *arg;               /* Argument passed to callback */
   uint64_t expired;            /* Absolute expiration time (ns) */
+#ifdef CONFIG_SMP
   uint8_t cpus;                /* Number of cpus that are running the timer */
+#endif
 };
 
 /****************************************************************************
@@ -142,7 +144,9 @@ void hrtimer_init(FAR hrtimer_t *hrtimer,
   hrtimer->state = HRTIMER_STATE_INACTIVE;
   hrtimer->func = func;
   hrtimer->arg = arg;
+#ifdef CONFIG_SMP
   hrtimer->cpus = 0;
+#endif
 }
 
 /****************************************************************************

sched/hrtimer/hrtimer_cancel.c

@@ -41,8 +41,12 @@
 
 #define HRTIMER_CANCEL_SYNC_DELAY_MS  5
 
-#define hrtimer_is_free(hrtimer) (((hrtimer)->state == HRTIMER_STATE_INACTIVE) && \
-                                  ((hrtimer)->cpus == 0))
+#ifdef CONFIG_SMP
+#  define hrtimer_is_free(hrtimer) (((hrtimer)->state == HRTIMER_STATE_INACTIVE) && \
+                                    ((hrtimer)->cpus == 0))
+#else
+#  define hrtimer_is_free(hrtimer) (((hrtimer)->state == HRTIMER_STATE_INACTIVE))
+#endif
 
 /****************************************************************************
  * Public Functions

sched/hrtimer/hrtimer_process.c

@@ -98,11 +98,14 @@ void hrtimer_process(uint64_t now)
       DEBUGASSERT(hrtimer->func != NULL);
 
       hrtimer->state = HRTIMER_STATE_RUNNING;
+
+#ifdef CONFIG_SMP
       hrtimer->cpus++;
 
       /* cpus is a running reference counter and must never wrap */
 
       DEBUGASSERT(hrtimer->cpus != 0);
+#endif
 
       /* Leave critical section before invoking the callback */
 
@@ -116,7 +119,9 @@ void hrtimer_process(uint64_t now)
 
       flags = spin_lock_irqsave(&g_hrtimer_spinlock);
 
+#ifdef CONFIG_SMP
       hrtimer->cpus--;
+#endif
 
       switch (hrtimer->state)
         {
@@ -137,11 +142,14 @@ void hrtimer_process(uint64_t now)
               else
                 {
                   /* One-shot timer: deactivate when last instance ends */
-
+#ifdef CONFIG_SMP
                   if (hrtimer->cpus == 0)
                     {
+#endif
                       hrtimer->state = HRTIMER_STATE_INACTIVE;
+#ifdef CONFIG_SMP
                     }
+#endif
                 }
 
               break;
@@ -151,10 +159,14 @@ void hrtimer_process(uint64_t now)
             {
               /* Timer was canceled during callback execution */
 
+#ifdef CONFIG_SMP
               if (hrtimer->cpus == 0)
                 {
+#endif
                   hrtimer->state = HRTIMER_STATE_INACTIVE;
+#ifdef CONFIG_SMP
                 }
+#endif
 
               break;
             }