[PATCH 2/2] KVM: PPC: use ticks, not usecs, for exit timing

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From: Stuart Yoder <stuart.yoder@xxxxxxxxxxxxx>

Convert to microseconds when displaying
(with fix from Bharat Bhushan <Bharat.Bhushan@xxxxxxxxxxxxx>).

This reduces rounding error with large quantities of short exits.

Signed-off-by: Stuart Yoder <stuart.yoder@xxxxxxxxxxxxx>
Signed-off-by: Scott Wood <scottwood@xxxxxxxxxxxxx>
---
 arch/powerpc/kvm/timing.c |   30 +++++++++++++++++-------------
 1 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kvm/timing.c b/arch/powerpc/kvm/timing.c
index a021f58..5f79d91 100644
--- a/arch/powerpc/kvm/timing.c
+++ b/arch/powerpc/kvm/timing.c
@@ -56,15 +56,6 @@ static void add_exit_timing(struct kvm_vcpu *vcpu, u64 duration, int type)
 {
 	u64 old;
 
-	do_div(duration, tb_ticks_per_usec);
-	if (unlikely(duration > 0xFFFFFFFF)) {
-		printk(KERN_ERR"%s - duration too big -> overflow"
-			" duration %lld type %d exit #%d\n",
-			__func__, duration, type,
-			vcpu->arch.timing_count_type[type]);
-		return;
-	}
-
 	vcpu->arch.timing_count_type[type]++;
 
 	/* sum */
@@ -147,17 +138,30 @@ static int kvmppc_exit_timing_show(struct seq_file *m, void *private)
 {
 	struct kvm_vcpu *vcpu = m->private;
 	int i;
+	u64 min, max, sum, sum_quad;
 
 	seq_printf(m, "%s", "type	count	min	max	sum	sum_squared\n");
 
+
 	for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) {
+
+		min = vcpu->arch.timing_min_duration[i];
+		do_div(min, tb_ticks_per_usec);
+		max = vcpu->arch.timing_max_duration[i];
+		do_div(max, tb_ticks_per_usec);
+		sum = vcpu->arch.timing_sum_duration[i];
+		do_div(sum, tb_ticks_per_usec);
+		sum_quad = vcpu->arch.timing_sum_quad_duration[i];
+		do_div(sum_quad, tb_ticks_per_usec);
+
 		seq_printf(m, "%12s	%10d	%10lld	%10lld	%20lld	%20lld\n",
 			kvm_exit_names[i],
 			vcpu->arch.timing_count_type[i],
-			vcpu->arch.timing_min_duration[i],
-			vcpu->arch.timing_max_duration[i],
-			vcpu->arch.timing_sum_duration[i],
-			vcpu->arch.timing_sum_quad_duration[i]);
+			min,
+			max,
+			sum,
+			sum_quad);
+
 	}
 	return 0;
 }
-- 
1.7.1

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