tools/kvm_stat: add new interactive command 'b'

Toggle display total number of events by guest (debugfs only).
When switching to display of events by guest, field filters remain
active. I.e. the number of events per guest reported considers only
events matching the filters. Likewise with pid/guest filtering.
Note that when switching to display of events by guest, DebugfsProvider
remains to collect data for events as it did before, but the read()
method summarizes the values by pid.
Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/kvm/kvm_stat/kvm_stat

@@ -662,7 +662,7 @@ class TracepointProvider(Provider):
         self.setup_traces()
         self.fields = self._fields
 
-    def read(self):
+    def read(self, by_guest=0):
         """Returns 'event name: current value' for all enabled events."""
         ret = defaultdict(int)
         for group in self.group_leaders:
@@ -731,7 +731,7 @@ class DebugfsProvider(Provider):
             self.do_read = True
         self.reset()
 
-    def read(self, reset=0):
+    def read(self, reset=0, by_guest=0):
         """Returns a dict with format:'file name / field -> current value'.
 
         Parameter 'reset':
@@ -762,8 +762,16 @@ class DebugfsProvider(Provider):
                     self._baseline[key] = 0
                 if self._baseline.get(key, -1) == -1:
                     self._baseline[key] = value
-                results[field] = (results.get(field, 0) + value -
-                                  self._baseline.get(key, 0))
+                increment = (results.get(field, 0) + value -
+                             self._baseline.get(key, 0))
+                if by_guest:
+                    pid = key.split('-')[0]
+                    if pid in results:
+                        results[pid] += increment
+                    else:
+                        results[pid] = increment
+                else:
+                    results[field] = increment
 
         return results
 
@@ -849,18 +857,44 @@ class Stats(object):
             for provider in self.providers:
                 provider.pid = self._pid_filter
 
-    def get(self):
+    def get(self, by_guest=0):
         """Returns a dict with field -> (value, delta to last value) of all
         provider data."""
         for provider in self.providers:
-            new = provider.read()
-            for key in provider.fields:
+            new = provider.read(by_guest=by_guest)
+            for key in new if by_guest else provider.fields:
                 oldval = self.values.get(key, (0, 0))[0]
                 newval = new.get(key, 0)
                 newdelta = newval - oldval
                 self.values[key] = (newval, newdelta)
         return self.values
 
+    def toggle_display_guests(self, to_pid):
+        """Toggle between collection of stats by individual event and by
+        guest pid
+
+        Events reported by DebugfsProvider change when switching to/from
+        reading by guest values. Hence we have to remove the excess event
+        names from self.values.
+
+        """
+        if any(isinstance(ins, TracepointProvider) for ins in self.providers):
+            return 1
+        if to_pid:
+            for provider in self.providers:
+                if isinstance(provider, DebugfsProvider):
+                    for key in provider.fields:
+                        if key in self.values.keys():
+                            del self.values[key]
+        else:
+            oldvals = self.values.copy()
+            for key in oldvals:
+                if key.isdigit():
+                    del self.values[key]
+        # Update oldval (see get())
+        self.get(to_pid)
+        return 0
+
 DELAY_DEFAULT = 3.0
 MAX_GUEST_NAME_LEN = 48
 MAX_REGEX_LEN = 44
@@ -876,6 +910,7 @@ class Tui(object):
         self._delay_initial = 0.25
         self._delay_regular = DELAY_DEFAULT
         self._sorting = SORT_DEFAULT
+        self._display_guests = 0
 
     def __enter__(self):
         """Initialises curses for later use.  Based on curses.wrapper
@@ -1024,8 +1059,12 @@ class Tui(object):
             if len(regex) > MAX_REGEX_LEN:
                 regex = regex[:MAX_REGEX_LEN] + '...'
             self.screen.addstr(1, 17, 'regex filter: {0}'.format(regex))
+        if self._display_guests:
+            col_name = 'Guest Name'
+        else:
+            col_name = 'Event'
         self.screen.addstr(2, 1, '%-40s %10s%7s %8s' %
-                           ('Event', 'Total', '%Total', 'CurAvg/s'),
+                           (col_name, 'Total', '%Total', 'CurAvg/s'),
                            curses.A_STANDOUT)
         self.screen.addstr(4, 1, 'Collecting data...')
         self.screen.refresh()
@@ -1034,7 +1073,7 @@ class Tui(object):
         row = 3
         self.screen.move(row, 0)
         self.screen.clrtobot()
-        stats = self.stats.get()
+        stats = self.stats.get(self._display_guests)
 
         def sortCurAvg(x):
             # sort by current events if available
@@ -1062,6 +1101,8 @@ class Tui(object):
                 break
             if values[0] is not None:
                 cur = int(round(values[1] / sleeptime)) if values[1] else ''
+                if self._display_guests:
+                    key = self.get_gname_from_pid(key)
                 self.screen.addstr(row, 1, '%-40s %10d%7.1f %8s' %
                                    (key, values[0], values[0] * 100 / total,
                                     cur))
@@ -1070,9 +1111,26 @@ class Tui(object):
             self.screen.addstr(4, 1, 'No matching events reported yet')
         self.screen.refresh()
 
+    def show_msg(self, text):
+        """Display message centered text and exit on key press"""
+        hint = 'Press any key to continue'
+        curses.cbreak()
+        self.screen.erase()
+        (x, term_width) = self.screen.getmaxyx()
+        row = 2
+        for line in text:
+            start = (term_width - len(line)) / 2
+            self.screen.addstr(row, start, line)
+            row += 1
+        self.screen.addstr(row + 1, (term_width - len(hint)) / 2, hint,
+                           curses.A_STANDOUT)
+        self.screen.getkey()
+
     def show_help_interactive(self):
         """Display help with list of interactive commands"""
-        msg = ('   c     clear filter',
+        msg = ('   b     toggle events by guests (debugfs only, honors'
+               ' filters)',
+               '   c     clear filter',
                '   f     filter by regular expression',
                '   g     filter by guest name',
                '   h     display interactive commands reference',
@@ -1253,6 +1311,14 @@ class Tui(object):
             sleeptime = self._delay_regular
             try:
                 char = self.screen.getkey()
+                if char == 'b':
+                    self._display_guests = not self._display_guests
+                    if self.stats.toggle_display_guests(self._display_guests):
+                        self.show_msg(['Command not available with tracepoints'
+                                       ' enabled', 'Restart with debugfs only '
+                                       '(see option \'-d\') and try again!'])
+                        self._display_guests = not self._display_guests
+                    self.refresh_header()
                 if char == 'c':
                     self.stats.fields_filter = DEFAULT_REGEX
                     self.refresh_header(0)
@@ -1356,6 +1422,7 @@ Requirements:
   the large number of files that are possibly opened.
 
 Interactive Commands:
+   b     toggle events by guests (debugfs only, honors filters)
    c     clear filter
    f     filter by regular expression
    g     filter by guest name

tools/kvm/kvm_stat/kvm_stat.txt

@@ -29,6 +29,8 @@ meaning of events.
 INTERACTIVE COMMANDS
 --------------------
 [horizontal]
+*b*::	toggle events by guests (debugfs only, honors filters)
+
 *c*::	clear filter
 
 *f*::	filter by regular expression