- Make SCHED_STATS more generic by adding a wrapper to create the

   variables and sysctl nodes.
 - In reset walk the children of kern_sched_stats and reset the counters
   via the oid_arg1 pointer.  This allows us to add arbitrary counters to
   the tree and still reset them properly.
 - Define a set of switch types to be passed with flags to mi_switch().
   These types are named SWT_*.  These types correspond to SCHED_STATS
   counters and are automatically handled in this way.
 - Make the new SWT_ types more specific than the older switch stats.
   There are now stats for idle switches, remote idle wakeups, remote
   preemption ithreads idling, etc.
 - Add switch statistics for ULE's pickcpu algorithm.  These stats include
   how much migration there is, how often affinity was successful, how
   often threads were migrated to the local cpu on wakeup, etc.

Sponsored by:	Nokia

1 files changed, 41 insertions, 25 deletions

diff --git a/sys/kern/kern_switch.c b/sys/kern/kern_switch.c
index 10bfb73dd3dc..b7cb0b6b82db 100644
--- a/sys/kern/kern_switch.c
+++ b/sys/kern/kern_switch.c
@@ -73,25 +73,35 @@ static int kern_sched_preemption = 0;
 SYSCTL_INT(_kern_sched, OID_AUTO, preemption, CTLFLAG_RD,
     &kern_sched_preemption, 0, "Kernel preemption enabled");
 
+/*
+ * Support for scheduler stats exported via kern.sched.stats.  All stats may
+ * be reset with kern.sched.stats.reset = 1.  Stats may be defined elsewhere
+ * with SCHED_STAT_DEFINE().
+ */
 #ifdef SCHED_STATS
-long switch_preempt;
-long switch_owepreempt;
-long switch_turnstile;
-long switch_sleepq;
-long switch_sleepqtimo;
-long switch_relinquish;
-long switch_needresched;
-static SYSCTL_NODE(_kern_sched, OID_AUTO, stats, CTLFLAG_RW, 0, "switch stats");
-SYSCTL_INT(_kern_sched_stats, OID_AUTO, preempt, CTLFLAG_RD, &switch_preempt, 0, "");
-SYSCTL_INT(_kern_sched_stats, OID_AUTO, owepreempt, CTLFLAG_RD, &switch_owepreempt, 0, "");
-SYSCTL_INT(_kern_sched_stats, OID_AUTO, turnstile, CTLFLAG_RD, &switch_turnstile, 0, "");
-SYSCTL_INT(_kern_sched_stats, OID_AUTO, sleepq, CTLFLAG_RD, &switch_sleepq, 0, "");
-SYSCTL_INT(_kern_sched_stats, OID_AUTO, sleepqtimo, CTLFLAG_RD, &switch_sleepqtimo, 0, "");
-SYSCTL_INT(_kern_sched_stats, OID_AUTO, relinquish, CTLFLAG_RD, &switch_relinquish, 0, "");
-SYSCTL_INT(_kern_sched_stats, OID_AUTO, needresched, CTLFLAG_RD, &switch_needresched, 0, "");
+long sched_switch_stats[SWT_COUNT];	/* Switch reasons from mi_switch(). */
+
+SYSCTL_NODE(_kern_sched, OID_AUTO, stats, CTLFLAG_RW, 0, "switch stats");
+SCHED_STAT_DEFINE_VAR(uncategorized, &sched_switch_stats[SWT_NONE], "");
+SCHED_STAT_DEFINE_VAR(preempt, &sched_switch_stats[SWT_PREEMPT], "");
+SCHED_STAT_DEFINE_VAR(owepreempt, &sched_switch_stats[SWT_OWEPREEMPT], "");
+SCHED_STAT_DEFINE_VAR(turnstile, &sched_switch_stats[SWT_TURNSTILE], "");
+SCHED_STAT_DEFINE_VAR(sleepq, &sched_switch_stats[SWT_SLEEPQ], "");
+SCHED_STAT_DEFINE_VAR(sleepqtimo, &sched_switch_stats[SWT_SLEEPQTIMO], "");
+SCHED_STAT_DEFINE_VAR(relinquish, &sched_switch_stats[SWT_RELINQUISH], "");
+SCHED_STAT_DEFINE_VAR(needresched, &sched_switch_stats[SWT_NEEDRESCHED], "");
+SCHED_STAT_DEFINE_VAR(idle, &sched_switch_stats[SWT_IDLE], "");
+SCHED_STAT_DEFINE_VAR(iwait, &sched_switch_stats[SWT_IWAIT], "");
+SCHED_STAT_DEFINE_VAR(suspend, &sched_switch_stats[SWT_SUSPEND], "");
+SCHED_STAT_DEFINE_VAR(remotepreempt, &sched_switch_stats[SWT_REMOTEPREEMPT],
+    "");
+SCHED_STAT_DEFINE_VAR(remotewakeidle, &sched_switch_stats[SWT_REMOTEWAKEIDLE],
+    "");
+
 static int
 sysctl_stats_reset(SYSCTL_HANDLER_ARGS)
 {
+	struct sysctl_oid *p;
         int error;
 	int val;
 
@@ -101,14 +111,15 @@ sysctl_stats_reset(SYSCTL_HANDLER_ARGS)
                 return (error);
         if (val == 0)
                 return (0);
-	switch_preempt = 0;
-	switch_owepreempt = 0;
-	switch_turnstile = 0;
-	switch_sleepq = 0;
-	switch_sleepqtimo = 0;
-	switch_relinquish = 0;
-	switch_needresched = 0;
-
+	/*
+	 * Traverse the list of children of _kern_sched_stats and reset each
+	 * to 0.  Skip the reset entry.
+	 */
+	SLIST_FOREACH(p, oidp->oid_parent, oid_link) {
+		if (p == oidp || p->oid_arg1 == NULL)
+			continue;
+		*(long *)p->oid_arg1 = 0;
+	}
 	return (0);
 }
 
@@ -164,6 +175,7 @@ void
 critical_exit(void)
 {
 	struct thread *td;
+	int flags;
 
 	td = curthread;
 	KASSERT(td->td_critnest != 0,
@@ -175,8 +187,12 @@ critical_exit(void)
 			td->td_critnest = 1;
 			thread_lock(td);
 			td->td_critnest--;
-			SCHED_STAT_INC(switch_owepreempt);
-			mi_switch(SW_INVOL|SW_PREEMPT, NULL);
+			flags = SW_INVOL | SW_PREEMPT;
+			if (TD_IS_IDLETHREAD(td))
+				flags |= SWT_IDLE;
+			else
+				flags |= SWT_OWEPREEMPT;
+			mi_switch(flags, NULL);
 			thread_unlock(td);
 		}
 	} else