adaptive: introduce optimizer hooks

Predict task weight, introduce optimizer run.

1 files changed, 33 insertions, 1 deletions

diff --git a/kernel/sched_adaptive.c b/kernel/sched_adaptive.c
index 6756bef0bf..f17807d31d 100644
--- a/kernel/sched_adaptive.c
+++ b/kernel/sched_adaptive.c
@@ -116,6 +116,13 @@ static LIST_HEAD(adaptive_cpu_queue);
 
 static rt_domain_t adaptive;
 
+/* feedback control parameters */
+static fp_t fc_a, fc_b, fc_c;
+
+/* optimizer trigger */
+static jiffie_t last_optimizer_run;
+static jiffie_t optimizer_period;
+static fp_t     task_error_threshold;
 
 static void set_service_level(struct task_struct* t, unsigned int level)
 {
@@ -132,6 +139,10 @@ static void set_service_level(struct task_struct* t, unsigned int level)
         TRACE_TASK(t, "service level %u activated\n", level);
 }
 
+void adaptive_optimize(void)
+{
+        last_optimizer_run = jiffies;
+}
 
 /* update_cpu_position - Move the cpu entry to the correct place to maintain 
  *                       order in the cpu queue. Caller must hold adaptive lock.
@@ -362,7 +373,11 @@ static reschedule_check_t adaptive_scheduler_tick(void)
         if (get_rt_mode() == MODE_RT_RUN && smp_processor_id() == 0) {
                 queue_lock_irqsave(&adaptive_lock, flags);
                 
-                /* (1) try to release pending jobs */
+                /* (1) run the optimizer if it did not trigger often enough */
+                if (time_before_eq(last_optimizer_run + optimizer_period, jiffies))
+                        adaptive_optimize();
+
+                /* (2) try to release pending jobs */
                 adaptive_release_jobs();
 
                 /* we don't need to check linked != scheduled since
@@ -379,12 +394,20 @@ static reschedule_check_t adaptive_scheduler_tick(void)
 static noinline void job_completion(struct task_struct *t)
 {
         long delta;
+        fp_t actual_weight;
         BUG_ON(!t);
 
         sched_trace_job_completion(t);
         delta = t->rt_param.times.exec_time - 
                 t->rt_param.basic_params.exec_cost;
 
+        actual_weight = _frac(t->rt_param.times.exec_time, 
+                              t->rt_param.basic_params.period);
+        update_estimate(&t->rt_param.predictor_state, actual_weight, 
+                        fc_a, fc_b, fc_c);
+        if (_gt(t->rt_param.predictor_state.error, task_error_threshold))
+                adaptive_optimize();
+
         TRACE_TASK(t, "job %d completes, delta WCET = %d\n", 
                    t->rt_param.times.job_no, delta);
 
@@ -754,6 +777,8 @@ static int adaptive_mode_change(int new_mode)
                         list_add(&entry->list, &adaptive_cpu_queue);
                 }               
 
+                adaptive_optimize();
+                
                 queue_unlock_irqrestore(&adaptive_lock, flags);
 
         }
@@ -793,6 +818,13 @@ sched_plugin_t *__init init_adaptive_plugin(void)
         int cpu;
         cpu_entry_t *entry;
 
+        fc_a = FP(1);
+        fc_b = FP(1);
+        fc_c = FP(1);
+        
+        optimizer_period = 250;
+        task_error_threshold = _frac(1, 2);
+
         if (!s_plugin.ready_to_use)
         {
                 /* initialize CPU state */