[Xen-devel] [PATCH RFC 35/49] xen/sched: add runstate counters to struct sched_item

[Juergen Gross <jgross@xxxxxxxx>]

Add counters to struct sched_item indicating how many vcpus are either
running/runnable or blocked/paused. The counters are updated when a
vcpu runstate is changed.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/common/schedule.c      | 27 +++++++++++++++++++++++++++
 xen/include/xen/sched-if.h |  4 ++++
 2 files changed, 31 insertions(+)

diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index 5a12d9bdc7..0a94505b89 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -178,6 +178,7 @@ static inline void vcpu_runstate_change(
     struct vcpu *v, int new_state, s_time_t new_entry_time)
 {
     s_time_t delta;
+    bool old_run, new_run;
 
     ASSERT(v->runstate.state != new_state);
     ASSERT(spin_is_locked(per_cpu(sched_res, v->processor)->schedule_lock));
@@ -186,6 +187,26 @@ static inline void vcpu_runstate_change(
 
     trace_runstate_change(v, new_state);
 
+    old_run = (v->runstate.state == RUNSTATE_running ||
+               v->runstate.state == RUNSTATE_runnable);
+    new_run = (new_state == RUNSTATE_running || new_state == 
RUNSTATE_runnable);
+
+    if ( old_run != new_run )
+    {
+        struct sched_item *item = v->sched_item;
+
+        if ( old_run )
+        {
+            item->run_cnt--;
+            item->idle_cnt++;
+        }
+        else
+        {
+            item->run_cnt++;
+            item->idle_cnt--;
+        }
+    }
+
     delta = new_entry_time - v->runstate.state_entry_time;
     if ( delta > 0 )
     {
@@ -362,9 +383,15 @@ int sched_init_vcpu(struct vcpu *v)
         return 1;
 
     if ( is_idle_domain(d) )
+    {
         processor = v->vcpu_id;
+        item->run_cnt++;
+    }
     else
+    {
         processor = sched_select_initial_cpu(v);
+        item->idle_cnt++;
+    }
 
     sched_set_res(item, per_cpu(sched_res, processor));
 
diff --git a/xen/include/xen/sched-if.h b/xen/include/xen/sched-if.h
index 38b403dfbf..795b2fafe5 100644
--- a/xen/include/xen/sched-if.h
+++ b/xen/include/xen/sched-if.h
@@ -62,6 +62,10 @@ struct sched_item {
     /* Last time item got (de-)scheduled. */
     uint64_t               state_entry_time;
 
+    /* Vcpu state summary. */
+    unsigned int           run_cnt;   /* vcpus running or runnable */
+    unsigned int           idle_cnt;  /* vcpus blocked or offline */
+
     /* Currently running on a CPU? */
     bool                   is_running;
     /* Item needs affinity restored */
-- 
2.16.4


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