tools/kvm_stat: group child events indented after parent

We keep the current logic that sorts all events (parent and child), but
re-shuffle the events afterwards, grouping the children after the
respective parent. Note that the percentage column for child events
gives the percentage of the parent's total.
Since we rework the logic anyway, we modify the total average
calculation to use the raw numbers instead of the (rounded) averages.
Note that this can result in differing numbers (between total average
and the sum of the individual averages) due to rounding errors.

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

tools/kvm/kvm_stat/kvm_stat

@@ -1124,6 +1124,45 @@ class Tui(object):
         def is_child_field(field):
             return field.find('(') != -1
 
+        def insert_child(sorted_items, child, values, parent):
+            num = len(sorted_items)
+            for i in range(0, num):
+                # only add child if parent is present
+                if parent.startswith(sorted_items[i][0]):
+                    sorted_items.insert(i + 1, ('  ' + child, values))
+
+        def get_sorted_events(self, stats):
+            """ separate parent and child events """
+            if self._sorting == SORT_DEFAULT:
+                def sortkey((_k, v)):
+                    # sort by (delta value, overall value)
+                    return (v.delta, v.value)
+            else:
+                def sortkey((_k, v)):
+                    # sort by overall value
+                    return v.value
+
+            childs = []
+            sorted_items = []
+            # we can't rule out child events to appear prior to parents even
+            # when sorted - separate out all children first, and add in later
+            for key, values in sorted(stats.items(), key=sortkey,
+                                      reverse=True):
+                if values == (0, 0):
+                    continue
+                if key.find(' ') != -1:
+                    if not self.stats.child_events:
+                        continue
+                    childs.insert(0, (key, values))
+                else:
+                    sorted_items.append((key, values))
+            if self.stats.child_events:
+                for key, values in childs:
+                    (child, parent) = key.split(' ')
+                    insert_child(sorted_items, child, values, parent)
+
+            return sorted_items
+
         row = 3
         self.screen.move(row, 0)
         self.screen.clrtobot()
@@ -1143,44 +1182,34 @@ class Tui(object):
             # we don't have any fields, or all non-child events are filtered
             total = ctotal
 
-        if self._sorting == SORT_DEFAULT:
-            def sortkey((_k, v)):
-                # sort by (delta value, overall value)
-                return (v.delta, v.value)
-        else:
-            def sortkey((_k, v)):
-                # sort by overall value
-                return v.value
-
-        sorted_items = sorted(stats.items(), key=sortkey, reverse=True)
-
         # print events
         tavg = 0
-        for key, values in sorted_items:
-            if row >= self.screen.getmaxyx()[0] - 1:
+        tcur = 0
+        for key, values in get_sorted_events(self, stats):
+            if row >= self.screen.getmaxyx()[0] - 1 or values == (0, 0):
                 break
-            if values == (0, 0):
-                continue
-            if not self.stats.child_events and key.find(' ') != -1:
-                continue
-            if values.value is not None:
-                cur = int(round(values.delta / sleeptime)) if values.delta else ''
-                if self._display_guests:
-                    key = self.get_gname_from_pid(key)
-                    if not key:
-                        continue
-                self.screen.addstr(row, 1, '%-40s %10d%7.1f %8s' % (key
-                                   .split(' ')[0], values.value,
-                                   values.value * 100 / total, cur))
-                if cur != '' and key.find('(') == -1:
-                    tavg += cur
+            if self._display_guests:
+                key = self.get_gname_from_pid(key)
+                if not key:
+                    continue
+            cur = int(round(values.delta / sleeptime)) if values.delta else ''
+            if key[0] != ' ':
+                if values.delta:
+                    tcur += values.delta
+                ptotal = values.value
+                ltotal = total
+            else:
+                ltotal = ptotal
+            self.screen.addstr(row, 1, '%-40s %10d%7.1f %8s' % (key,
+                               values.value,
+                               values.value * 100 / float(ltotal), cur))
             row += 1
         if row == 3:
             self.screen.addstr(4, 1, 'No matching events reported yet')
         else:
+            tavg = int(round(tcur / sleeptime)) if tcur > 0 else ''
             self.screen.addstr(row, 1, '%-40s %10d        %8s' %
-                               ('Total', total, tavg if tavg else ''),
-                               curses.A_BOLD)
+                               ('Total', total, tavg), curses.A_BOLD)
         self.screen.refresh()
 
     def _show_msg(self, text):