Add support for delays of different durations in work queue processing

include/nuttx/wqueue.h

@@ -44,7 +44,7 @@
 
 #include <sys/types.h>
 #include <stdint.h>
-#include <signal.h>
+#include <semaphore.h>
 #include <queue.h>
 
 /****************************************************************************
@@ -66,11 +66,14 @@
  *   build (CONFIG_SCHED_KERNEL=n) but must be defined in kernel mode
  *   in order to build the high priority work queue.
  * CONFIG_SCHED_WORKPRIORITY - The execution priority of the worker
- *   thread.  Default: 192
+ *   thread.  Default: 224
  * CONFIG_SCHED_WORKPERIOD - How often the worker thread checks for
- *   work in units of microseconds.  Default: 50*1000 (50 MS).
+ *   work in units of microseconds.  If the high priority worker thread is
+ *   performing garbage collection, then the default is 50*1000 (50 MS).
+ *   Otherwise, if the lower priority worker thread is performing garbage
+ *   collection, the default is 100*1000.
  * CONFIG_SCHED_WORKSTACKSIZE - The stack size allocated for the worker
- *   thread.  Default: CONFIG_IDLETHREAD_STACKSIZE.
+ *   thread.  Default: 2048.
  * CONFIG_SIG_SIGWORK - The signal number that will be used to wake-up
  *   the worker thread.  Default: 17
  *
@@ -86,7 +89,20 @@
  * CONFIG_SCHED_LPWORKPERIOD - How often the lower priority worker thread
  *  checks for work in units of microseconds.  Default: 50*1000 (50 MS).
  * CONFIG_SCHED_LPWORKSTACKSIZE - The stack size allocated for the lower
- *   priority worker thread.  Default: CONFIG_IDLETHREAD_STACKSIZE.
+ *   priority worker thread.  Default: 2048.
+ *
+ * The user-mode work queue is only available in the protected or kernel
+ * builds.  This those configurations, the user-mode work queue provides the
+ * same (non-standard) facility for use by applications.
+ *
+ * CONFIG_SCHED_USRWORK. If CONFIG_SCHED_USRWORK is also defined then the
+ *   user-mode work queue will be created.
+ * CONFIG_SCHED_USRWORKPRIORITY - The minimum execution priority of the lower
+ *   priority worker thread.  Default: 100
+ * CONFIG_SCHED_USRWORKPERIOD - How often the lower priority worker thread
+ *  checks for work in units of microseconds.  Default: 100*1000 (100 MS).
+ * CONFIG_SCHED_USRWORKSTACKSIZE - The stack size allocated for the lower
+ *   priority worker thread.  Default: 2048.
  */
 
 /* Is this a protected build (CONFIG_BUILD_PROTECTED=y) */
@@ -147,22 +163,20 @@
 
 #ifdef CONFIG_SCHED_WORKQUEUE
 
-/* We are building work queues... Work queues need signal support */
-
-#ifdef CONFIG_DISABLE_SIGNALS
-#  warning "Worker thread support requires signals"
-#endif
-
 /* High priority, kernel work queue configuration ***************************/
 
 #ifdef CONFIG_SCHED_HPWORK
 
 #  ifndef CONFIG_SCHED_WORKPRIORITY
-#    define CONFIG_SCHED_WORKPRIORITY 192
+#    define CONFIG_SCHED_WORKPRIORITY 224
 #  endif
 
 #  ifndef CONFIG_SCHED_WORKPERIOD
-#    define CONFIG_SCHED_WORKPERIOD (50*1000) /* 50 milliseconds */
+#    ifdef CONFIG_SCHED_LOWORK
+#      define CONFIG_SCHED_WORKPERIOD (100*1000) /* 100 milliseconds */
+#    else
+#      define CONFIG_SCHED_WORKPERIOD (50*1000)  /* 50 milliseconds */
+#    endif
 #  endif
 
 #  ifndef CONFIG_SCHED_WORKSTACKSIZE
@@ -223,11 +237,11 @@
 #ifdef CONFIG_SCHED_USRWORK
 
 #  ifndef CONFIG_SCHED_USRWORKPRIORITY
-#    define CONFIG_SCHED_USRWORKPRIORITY 50
+#    define CONFIG_SCHED_USRWORKPRIORITY 100
 #  endif
 
 #  ifndef CONFIG_SCHED_USRWORKPERIOD
-#    define CONFIG_SCHED_USRWORKPERIOD (50*1000) /* 50 milliseconds */
+#    define CONFIG_SCHED_USRWORKPERIOD (100*1000) /* 100 milliseconds */
 #  endif
 
 #  ifndef CONFIG_SCHED_USRWORKSTACKSIZE
@@ -286,8 +300,9 @@
 
 struct wqueue_s
 {
-  pid_t             pid; /* The task ID of the worker thread */
-  struct dq_queue_s q;   /* The queue of pending work */
+  uint32_t          delay;  /* Delay between polling cycles (ticks) */
+  struct dq_queue_s q;      /* The queue of pending work */
+  pid_t             pid[1]; /* The task ID of the worker thread(s) */
 };
 
 /* Defines the work callback */

libc/Kconfig

@@ -421,7 +421,7 @@ if SCHED_HPWORK
 
 config SCHED_WORKPRIORITY
 	int "High priority worker thread priority"
-	default 192
+	default 224
 	---help---
 		The execution priority of the higher priority worker thread.
 
@@ -440,10 +440,14 @@ config SCHED_WORKPRIORITY
 
 config SCHED_WORKPERIOD
 	int "High priority worker thread period"
-	default 50000
+	default 100000 if SCHED_LPWORK
+	default 50000 if !SCHED_LPWORK
 	---help---
 		How often the worker thread checks for work in units of microseconds.
-		Default: 50*1000 (50 MS).
+		Default:  If the high priority worker thread is performing garbage
+		collection, then the default is 50*1000 (50 MS).  Otherwise, if the
+		lower priority worker thread is performing garbage collection, the
+		default is 100*1000.
 
 config SCHED_WORKSTACKSIZE
 	int "High priority worker thread stack size"
@@ -452,6 +456,8 @@ config SCHED_WORKSTACKSIZE
 	---help---
 		The stack size allocated for the worker thread.  Default: 2K.
 
+endif # SCHED_HPWORK
+
 config SCHED_LPWORK
 	bool "Low priority (kernel) worker thread"
 	default n
@@ -533,7 +539,6 @@ config SCHED_LPWORKSTACKSIZE
 		The stack size allocated for the lower priority worker thread.  Default: 2K.
 
 endif # SCHED_LPWORK
-endif # SCHED_HPWORK
 
 if BUILD_PROTECTED
 
@@ -545,20 +550,20 @@ config SCHED_USRWORK
 
 if SCHED_USRWORK
 
-config SCHED_LPWORKPRIORITY
+config SCHED_USRWORKPRIORITY
 	int "User mode priority worker thread priority"
-	default 50
+	default 100
 	---help---
 		The execution priority of the lopwer priority worker thread.  Default: 192
 
-config SCHED_LPWORKPERIOD
+config SCHED_USRWORKPERIOD
 	int "User mode worker thread period"
-	default 50000
+	default 100000
 	---help---
 		How often the lower priority worker thread checks for work in units
-		of microseconds. Default: 50*1000 (50 MS).
+		of microseconds. Default: 100*1000 (100 MS).
 
-config SCHED_LPWORKSTACKSIZE
+config SCHED_USRWORKSTACKSIZE
 	int "User mode worker thread stack size"
 	default 2048
 	---help---

libc/wqueue/work_process.c

@@ -64,9 +64,9 @@
 #  define WORK_CLOCK CLOCK_REALTIME
 #endif
 
-/* The work poll period is in system ticks. */
-
-#define WORKPERIOD_TICKS  (CONFIG_SCHED_WORKPERIOD / USEC_PER_TICK)
+#ifndef MIN
+#  define MIN(a,b) ((a) < (b) ? (a) : (b))
+#endif
 
 /****************************************************************************
  * Private Type Declarations
@@ -121,7 +121,7 @@ void work_process(FAR struct wqueue_s *wqueue)
    * we process items in the work list.
    */
 
-  next  = WORKPERIOD_TICKS;
+  next  = wqueue->delay;
   flags = irqsave();
 
   /* Get the time that we started this polling cycle in clock ticks. */
@@ -221,18 +221,28 @@ void work_process(FAR struct wqueue_s *wqueue)
         }
     }
 
-  /* There is no work to be performed now.  Check if we need to delay or if we have
-   * already exceed the duration of the polling period.
-   */
+  /* Get the delay (in clock ticks) since we started the sampling */
 
-  if (next < WORKPERIOD_TICKS)
+  elapsed = clock_systimer() - work->qtime;
+  if (elapsed <= wqueue->delay)
     {
-      /* Wait awhile to check the work list.  We will wait here until either
-       * the time elapses or until we are awakened by a signal.  Interrupts
-       * will be re-enabled while we wait.
+      /* How must time would we need to delay to get to the end of the 
+       * sampling period?  The amount of time we delay should be the smaller
+       * of the time to the end of the sampling period and the time to the
+       * next work expiry.
        */
 
-      usleep(next * USEC_PER_TICK);
+      remaining = wqueue->delay - elapsed;
+      next      = MIN(next, remaining);
+      if (next > 0)
+        {
+          /* Wait awhile to check the work list.  We will wait here until
+           * either the time elapses or until we are awakened by a signal.
+           * Interrupts will be re-enabled while we wait.
+           */
+
+          usleep(next * USEC_PER_TICK);
+        }
     }
 
   irqrestore(flags);

libc/wqueue/work_queue.c

@@ -127,7 +127,7 @@ int work_qqueue(FAR struct wqueue_s *wqueue, FAR struct work_s *work,
   work->qtime  = clock_systimer(); /* Time work queued */
 
   dq_addlast((FAR dq_entry_t *)work, &wqueue->q);
-  kill(wqueue->pid, SIGWORK);      /* Wake up the worker thread */
+  kill(wqueue->pid[0], SIGWORK);   /* Wake up the worker thread */
 
   irqrestore(flags);
   return OK;

libc/wqueue/work_signal.c

@@ -96,7 +96,7 @@ int work_signal(int qid)
     {
       /* Signal the worker thread */
 
-      ret = kill(g_usrwork.pid, SIGWORK);
+      ret = kill(g_usrwork.pid[0], SIGWORK);
       if (ret < 0)
         {
           int errcode = errno;

libc/wqueue/work_usrthread.c

@@ -44,6 +44,7 @@
 #include <debug.h>
 
 #include <nuttx/wqueue.h>
+#include <nuttx/clock.h>
 
 #if defined(CONFIG_SCHED_WORKQUEUE) && defined(CONFIG_SCHED_USRWORK) && \
    !defined(__KERNEL__)
@@ -130,20 +131,21 @@ int work_usrstart(void)
 {
   /* Initialize work queue data structures */
 
+  g_usrwork.delay = CONFIG_SCHED_USRWORKPERIOD / USEC_PER_TICK;
   dq_init(&g_usrwork.q);
 
   /* Start a user-mode worker thread for use by applications. */
 
   svdbg("Starting user-mode worker thread\n");
 
-  g_usrwork.pid = task_create("uwork",
-                              CONFIG_SCHED_USRWORKPRIORITY,
-                              CONFIG_SCHED_USRWORKSTACKSIZE,
-                              (main_t)work_usrthread,
-                              (FAR char * const *)NULL);
+  g_usrwork.pid[0] = task_create("uwork",
+                                  CONFIG_SCHED_USRWORKPRIORITY,
+                                  CONFIG_SCHED_USRWORKSTACKSIZE,
+                                  (main_t)work_usrthread,
+                                  (FAR char * const *)NULL);
 
-  DEBUGASSERT(g_usrwork.pid > 0);
-  if (g_usrwork.pid < 0)
+  DEBUGASSERT(g_usrwork.pid[0] > 0);
+  if (g_usrwork.pid[0] < 0)
     {
       int errcode = errno;
       DEBUGASSERT(errcode > 0);
@@ -152,7 +154,7 @@ int work_usrstart(void)
       return -errcode;
     }
 
-  return g_usrwork.pid;
+  return g_usrwork.pid[0];
 }
 
 #endif /* CONFIG_SCHED_WORKQUEUE && CONFIG_SCHED_USRWORK && !__KERNEL__*/

sched/wqueue/kwork_hpthread.c

@@ -46,6 +46,7 @@
 #include <nuttx/wqueue.h>
 #include <nuttx/kthread.h>
 #include <nuttx/kmalloc.h>
+#include <nuttx/clock.h>
 
 #include "wqueue/wqueue.h"
 
@@ -151,19 +152,20 @@ int work_hpstart(void)
 {
   /* Initialize work queue data structures */
 
+  g_hpwork.delay = CONFIG_SCHED_WORKPERIOD / USEC_PER_TICK;
   dq_init(&g_hpwork.q);
 
   /* Start the high-priority, kernel mode worker thread */
 
   svdbg("Starting high-priority kernel worker thread\n");
 
-  g_hpwork.pid = kernel_thread(HPWORKNAME, CONFIG_SCHED_WORKPRIORITY,
-                               CONFIG_SCHED_WORKSTACKSIZE,
-                               (main_t)work_hpthread,
-                               (FAR char * const *)NULL);
+  g_hpwork.pid[0] = kernel_thread(HPWORKNAME, CONFIG_SCHED_WORKPRIORITY,
+                                  CONFIG_SCHED_WORKSTACKSIZE,
+                                  (main_t)work_hpthread,
+                                  (FAR char * const *)NULL);
 
-  DEBUGASSERT(g_hpwork.pid > 0);
-  if (g_hpwork.pid < 0)
+  DEBUGASSERT(g_hpwork.pid[0] > 0);
+  if (g_hpwork.pid[0] < 0)
     {
       int errcode = errno;
       DEBUGASSERT(errcode > 0);
@@ -172,7 +174,7 @@ int work_hpstart(void)
       return -errcode;
     }
 
-  return g_hpwork.pid;
+  return g_hpwork.pid[0];
 }
 
 #endif /* CONFIG_SCHED_WORKQUEUE && CONFIG_SCHED_HPWORK*/

sched/wqueue/kwork_inherit.c

@@ -91,7 +91,7 @@ void lpwork_boostpriority(uint8_t reqprio)
    * thread from the process ID.
    */
 
-  wpid = g_lpwork.pid;
+  wpid = g_lpwork.pid[0];
   wtcb = sched_gettcb(wpid);
 
   /* Prevent context switches until we get the priorities right */
@@ -214,7 +214,7 @@ void lpwork_restorepriority(uint8_t reqprio)
    * thread from the process ID.
    */
 
-  wpid = g_lpwork.pid;
+  wpid = g_lpwork.pid[0];
   wtcb = sched_gettcb(wpid);
 
   /* Prevent context switches until we get the priorities right */