tools/kvm_stat: fix child trace events accounting

Child trace events were included in calculation of the overall total,
which is used for calculation of the percentages of the '%Total' column.
However, the parent trace envents' stats summarize the child trace
events, hence we'd incorrectly account for them twice, leading to
slightly wrong stats.
With this fix, we use the correct total. Consequently, the sum of the
child trace events' '%Total' column values is identical to the
respective value of the respective parent event. However, this also
means that the sum of the '%Total' column values will aggregate to more
than 100 percent.

Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2 files changed, 5 insertions, 3 deletions

diff --git a/tools/kvm/kvm_stat/kvm_stat b/tools/kvm/kvm_stat/kvm_stat
index 4faf9f85a00e..90f0445d7808 100755
--- a/tools/kvm/kvm_stat/kvm_stat
+++ b/tools/kvm/kvm_stat/kvm_stat
@@ -1092,14 +1092,14 @@ class Tui(object):
             # sort by totals
             return (0, -stats[x][0])
         total = 0.
-        for val in stats.values():
-            total += val[0]
+        for key in stats.keys():
+            if key.find('(') is -1:
+                total += stats[key][0]
         if self._sorting == SORT_DEFAULT:
             sortkey = sortCurAvg
         else:
             sortkey = sortTotal
         for key in sorted(stats.keys(), key=sortkey):
-
             if row >= self.screen.getmaxyx()[0]:
                 break
             values = stats[key]
diff --git a/tools/kvm/kvm_stat/kvm_stat.txt b/tools/kvm/kvm_stat/kvm_stat.txt
index e5cf836be8a1..75368a3c285f 100644
--- a/tools/kvm/kvm_stat/kvm_stat.txt
+++ b/tools/kvm/kvm_stat/kvm_stat.txt
@@ -50,6 +50,8 @@ INTERACTIVE COMMANDS
 *s*::   set update interval
 
 *x*::   toggle reporting of stats for child trace events
+ ::     *Note*: The stats for the parents summarize the respective child trace
+                events
 
 Press any other key to refresh statistics immediately.