Pfair: various fixes concerning release timers

1 files changed, 52 insertions, 19 deletions

diff --git a/litmus/sched_pfair.c b/litmus/sched_pfair.c
index 055ac623edb4..e3db82a2bdf8 100644
--- a/litmus/sched_pfair.c
+++ b/litmus/sched_pfair.c
@@ -77,8 +77,9 @@ struct pfair_state {
         struct task_struct* local;     /* the local copy of linked          */
         struct task_struct* scheduled; /* what is actually scheduled        */
 
-        unsigned long missed_quanta;
         lt_t offset;                    /* stagger offset */
+        unsigned int missed_updates;
+        unsigned int missed_quanta;
 };
 
 struct pfair_cluster {
@@ -289,6 +290,15 @@ static void drop_all_references(struct task_struct *t)
         }
 }
 
+static void pfair_prepare_next_period(struct task_struct* t)
+{
+        struct pfair_param* p = tsk_pfair(t);
+
+        prepare_for_next_period(t);
+        get_rt_flags(t) = RT_F_RUNNING;
+        p->release += p->period;
+}
+
 /* returns 1 if the task needs to go the release queue */
 static int advance_subtask(quanta_t time, struct task_struct* t, int cpu)
 {
@@ -297,10 +307,8 @@ static int advance_subtask(quanta_t time, struct task_struct* t, int cpu)
         p->cur = (p->cur + 1) % p->quanta;
         if (!p->cur) {
                 if (tsk_rt(t)->present) {
-                        /* we start a new job */
-                        prepare_for_next_period(t);
-                        get_rt_flags(t) = RT_F_RUNNING;
-                        p->release += p->period;
+                        /* The job overran; we start a new budget allocation. */
+                        pfair_prepare_next_period(t);
                 } else {
                         /* remove task from system until it wakes */
                         drop_all_references(t);
@@ -310,14 +318,13 @@ static int advance_subtask(quanta_t time, struct task_struct* t, int cpu)
                 }
         }
         to_relq = time_after(cur_release(t), time);
-        TRACE_TASK(t, "on %d advanced to subtask %lu -> to_relq=%d\n",
-                   cpu, p->cur, to_relq);
+        TRACE_TASK(t, "on %d advanced to subtask %lu -> to_relq=%d (cur_release:%lu time:%lu)\n",
+                   cpu, p->cur, to_relq, cur_release(t), time);
         return to_relq;
 }
 
 static void advance_subtasks(struct pfair_cluster *cluster, quanta_t time)
 {
-        int missed;
         struct task_struct* l;
         struct pfair_param* p;
         struct list_head* pos;
@@ -326,15 +333,17 @@ static void advance_subtasks(struct pfair_cluster *cluster, quanta_t time)
         list_for_each(pos, &cluster->topology.cpus) {
                 cpu = from_cluster_list(pos);
                 l = cpu->linked;
-                missed = cpu->linked != cpu->local;
+                cpu->missed_updates += cpu->linked != cpu->local;
                 if (l) {
                         p = tsk_pfair(l);
                         p->last_quantum = time;
                         p->last_cpu     =  cpu_id(cpu);
                         if (advance_subtask(time, l, cpu_id(cpu))) {
-                                cpu->linked = NULL;
-                                sched_trace_task_release(l);
-                                add_release(&cluster->pfair, l);
+                                //cpu->linked = NULL;
+                                PTRACE_TASK(l, "should go to release queue. "
+                                            "scheduled_on=%d present=%d\n",
+                                            tsk_rt(l)->scheduled_on,
+                                            tsk_rt(l)->present);
                         }
                 }
         }
@@ -455,7 +464,7 @@ static void schedule_next_quantum(struct pfair_cluster *cluster, quanta_t time)
         list_for_each(pos, &cluster->topology.cpus) {
                 cpu = from_cluster_list(pos);
                 if (cpu->linked)
-                        PTRACE_TASK(pstate[cpu]->linked,
+                        PTRACE_TASK(cpu->linked,
                                     " linked on %d.\n", cpu_id(cpu));
                 else
                         PTRACE("(null) linked on %d.\n", cpu_id(cpu));
@@ -590,23 +599,40 @@ static int safe_to_schedule(struct task_struct* t, int cpu)
 static struct task_struct* pfair_schedule(struct task_struct * prev)
 {
         struct pfair_state* state = &__get_cpu_var(pfair_state);
-        int blocks;
+        struct pfair_cluster* cluster = cpu_cluster(state);
+        int blocks, completion, out_of_time;
         struct task_struct* next = NULL;
 
 #ifdef CONFIG_RELEASE_MASTER
         /* Bail out early if we are the release master.
          * The release master never schedules any real-time tasks.
          */
-        if (cpu_cluster(state)->pfair.release_master == cpu_id(state))
+        if (unlikely(cluster->pfair.release_master == cpu_id(state)))
                 return NULL;
 #endif
 
         raw_spin_lock(cpu_lock(state));
 
-        if (is_realtime(prev) && get_rt_flags(prev) == RT_F_SLEEP)
+        blocks      = is_realtime(prev) && !is_running(prev);
+        completion  = is_realtime(prev) && get_rt_flags(prev) == RT_F_SLEEP;
+        out_of_time = is_realtime(prev) && time_after(cur_release(prev),
+                                                      state->local_tick);
+
+        if (is_realtime(prev))
+            PTRACE_TASK(prev, "blocks:%d completion:%d out_of_time:%d\n",
+                        blocks, completion, out_of_time);
+
+        if (completion) {
                 sched_trace_task_completion(prev, 0);
+                pfair_prepare_next_period(prev);
+                prepare_release(prev, cur_release(prev));
+        }
 
-        blocks  = is_realtime(prev) && !is_running(prev);
+        if (!blocks && (completion || out_of_time)) {
+                drop_all_references(prev);
+                sched_trace_task_release(prev);
+                add_release(&cluster->pfair, prev);
+        }
 
         if (state->local && safe_to_schedule(state->local, cpu_id(state)))
                 next = state->local;
@@ -679,9 +705,12 @@ static void pfair_task_wake_up(struct task_struct *t)
                 release_at(t, now);
                 prepare_release(t, time2quanta(now, CEIL));
                 sched_trace_task_release(t);
-                __add_ready(&cluster->pfair, t);
         }
 
+        /* only add to ready queue if the task isn't still linked somewhere */
+        if (tsk_rt(t)->linked_on == NO_CPU)
+                __add_ready(&cluster->pfair, t);
+
         check_preempt(t);
 
         raw_spin_unlock_irqrestore(cluster_lock(cluster), flags);
@@ -879,8 +908,11 @@ static void cleanup_clusters(void)
         num_pfair_clusters = 0;
 
         /* avoid stale pointers */
-        for (i = 0; i < num_online_cpus(); i++)
+        for (i = 0; i < num_online_cpus(); i++) {
                 pstate[i]->topology.cluster = NULL;
+                printk("P%d missed %u updates and %u quanta.\n", cpu_id(pstate[i]),
+                       pstate[i]->missed_updates, pstate[i]->missed_quanta);
+        }
 }
 
 static long pfair_activate_plugin(void)
@@ -926,6 +958,7 @@ static long pfair_activate_plugin(void)
                 state->cur_tick   = now;
                 state->local_tick = now;
                 state->missed_quanta = 0;
+                state->missed_updates = 0;
                 state->offset     = cpu_stagger_offset(i);
                 printk(KERN_ERR "cpus[%d] set; %d\n", i, num_online_cpus());
                 cpus[i] = &state->topology;