tools/kvm_stat: Misc Patches

index 581278c..8cc83a30 100755
@@ -812,6 +812,13 @@ class Tui(object):
         except:
             pass
 
+        # Hide cursor in extra statement as some monochrome terminals
+        # might support hiding but not colors.
+        try:
+            curses.curs_set(0)
+        except curses.error:
+            pass
+
         curses.use_default_colors()
         return self
 

index 8cc83a30..ef47ad7 100755
@@ -809,7 +809,7 @@ class Tui(object):
         # return from C start_color() is ignorable.
         try:
             curses.start_color()
-        except:
+        except curses.error:
             pass
 
         # Hide cursor in extra statement as some monochrome terminals

index ef47ad7..14536c0 100755
@@ -969,12 +969,15 @@ class Tui(object):
 
 def batch(stats):
     """Prints statistics in a key, value format."""
-    s = stats.get()
-    time.sleep(1)
-    s = stats.get()
-    for key in sorted(s.keys()):
-        values = s[key]
-        print '%-42s%10d%10d' % (key, values[0], values[1])
+    try:
+        s = stats.get()
+        time.sleep(1)
+        s = stats.get()
+        for key in sorted(s.keys()):
+            values = s[key]
+            print '%-42s%10d%10d' % (key, values[0], values[1])
+    except KeyboardInterrupt:
+        pass
 
 def log(stats):
     """Prints statistics as reiterating key block, multiple value blocks."""

@@ -991,11 +994,14 @@ def log(stats):
     line = 0
     banner_repeat = 20
     while True:
-        time.sleep(1)
-        if line % banner_repeat == 0:
-            banner()
-        statline()
-        line += 1
+        try:
+            time.sleep(1)
+            if line % banner_repeat == 0:
+                banner()
+            statline()
+            line += 1
+        except KeyboardInterrupt:
+            break
 
 def get_options():
     """Returns processed program arguments."""

index 14536c0..231186a 100755
@@ -31,7 +31,6 @@ import resource
 import struct
 import re
 from collections import defaultdict
-from time import sleep
 
 VMX_EXIT_REASONS = {
     'EXCEPTION_NMI':        0,

@@ -657,6 +656,7 @@ class DebugfsProvider(object):
         self._fields = self.get_available_fields()
         self._pid = 0
         self.do_read = True
+        self.paths = []
 
     def get_available_fields(self):
         """"Returns a list of available fields.

@@ -794,7 +794,6 @@ class Tui(object):
     def __init__(self, stats):
         self.stats = stats
         self.screen = None
-        self.drilldown = False
         self.update_drilldown()
 
     def __enter__(self):

@@ -950,11 +949,10 @@ class Tui(object):
         while True:
             self.refresh(sleeptime)
             curses.halfdelay(int(sleeptime * 10))
-            sleeptime = 3
+            sleeptime = 3.0
             try:
                 char = self.screen.getkey()
                 if char == 'x':
-                    self.drilldown = not self.drilldown
                     self.update_drilldown()
                 if char == 'q':
                     break

@@ -1064,12 +1062,12 @@ Requirements:
                          help='fields to display (regex)',
                          )
     optparser.add_option('-p', '--pid',
-                        action='store',
-                        default=0,
-                        type=int,
-                        dest='pid',
-                        help='restrict statistics to pid',
-                        )
+                         action='store',
+                         default=0,
+                         type='int',
+                         dest='pid',
+                         help='restrict statistics to pid',
+                         )
     (options, _) = optparser.parse_args(sys.argv)
     return options
 

@@ -1099,8 +1097,8 @@ def check_access(options):
                          "Also ensure, that the kvm modules are loaded.\n")
         sys.exit(1)
 
-    if not os.path.exists(PATH_DEBUGFS_TRACING) and (options.tracepoints
-                                                     or not options.debugfs):
+    if not os.path.exists(PATH_DEBUGFS_TRACING) and (options.tracepoints or
+                                                     not options.debugfs):
         sys.stderr.write("Please enable CONFIG_TRACING in your kernel "
                          "when using the option -t (default).\n"
                          "If it is enabled, make {0} readable by the "

@@ -1111,7 +1109,7 @@ def check_access(options):
 
         sys.stderr.write("Falling back to debugfs statistics!\n")
         options.debugfs = True
-        sleep(5)
+        time.sleep(5)
 
     return options
 

index 231186a..6207843 100755
@@ -550,6 +550,7 @@ class TracepointProvider(object):
     def setup_traces(self):
         """Creates all event and group objects needed to be able to retrieve
         data."""
+        fields = self.get_available_fields()
         if self._pid > 0:
             # Fetch list of all threads of the monitored pid, as qemu
             # starts a thread for each vcpu.

@@ -560,7 +561,7 @@ class TracepointProvider(object):
 
         # The constant is needed as a buffer for python libs, std
         # streams and other files that the script opens.
-        newlim = len(groupids) * len(self._fields) + 50
+        newlim = len(groupids) * len(fields) + 50
         try:
             softlim_, hardlim = resource.getrlimit(resource.RLIMIT_NOFILE)
 

@@ -576,7 +577,7 @@ class TracepointProvider(object):
 
         for groupid in groupids:
             group = Group()
-            for name in self._fields:
+            for name in fields:
                 tracepoint = name
                 tracefilter = None
                 match = re.match(r'(.*)\((.*)\)', name)

index 6207843..5c4f248 100755
@@ -224,6 +224,7 @@ IOCTL_NUMBERS = {
     'RESET':       0x00002403,
 }
 
+
 class Arch(object):
     """Encapsulates global architecture specific data.
 

@@ -254,12 +255,14 @@ class Arch(object):
                     return ArchX86(SVM_EXIT_REASONS)
                 return
 
+
 class ArchX86(Arch):
     def __init__(self, exit_reasons):
         self.sc_perf_evt_open = 298
         self.ioctl_numbers = IOCTL_NUMBERS
         self.exit_reasons = exit_reasons
 
+
 class ArchPPC(Arch):
     def __init__(self):
         self.sc_perf_evt_open = 319

@@ -274,12 +277,14 @@ class ArchPPC(Arch):
         self.ioctl_numbers['SET_FILTER'] = 0x80002406 | char_ptr_size << 16
         self.exit_reasons = {}
 
+
 class ArchA64(Arch):
     def __init__(self):
         self.sc_perf_evt_open = 241
         self.ioctl_numbers = IOCTL_NUMBERS
         self.exit_reasons = AARCH64_EXIT_REASONS
 
+
 class ArchS390(Arch):
     def __init__(self):
         self.sc_perf_evt_open = 331

@@ -341,6 +346,7 @@ def get_filters():
 libc = ctypes.CDLL('libc.so.6', use_errno=True)
 syscall = libc.syscall
 
+
 class perf_event_attr(ctypes.Structure):
     """Struct that holds the necessary data to set up a trace event.
 

@@ -369,6 +375,7 @@ class perf_event_attr(ctypes.Structure):
         self.size = ctypes.sizeof(self)
         self.read_format = PERF_FORMAT_GROUP
 
+
 def perf_event_open(attr, pid, cpu, group_fd, flags):
     """Wrapper for the sys_perf_evt_open() syscall.
 

@@ -394,6 +401,7 @@ PERF_FORMAT_GROUP = 1 << 3
 PATH_DEBUGFS_TRACING = '/sys/kernel/debug/tracing'
 PATH_DEBUGFS_KVM = '/sys/kernel/debug/kvm'
 
+
 class Group(object):
     """Represents a perf event group."""
 

@@ -426,6 +434,7 @@ class Group(object):
                         struct.unpack(read_format,
                                       os.read(self.events[0].fd, length))))
 
+
 class Event(object):
     """Represents a performance event and manages its life cycle."""
     def __init__(self, name, group, trace_cpu, trace_pid, trace_point,

@@ -509,6 +518,7 @@ class Event(object):
         """Resets the count of the trace event in the kernel."""
         fcntl.ioctl(self.fd, ARCH.ioctl_numbers['RESET'], 0)
 
+
 class TracepointProvider(object):
     """Data provider for the stats class.
 

@@ -650,6 +660,7 @@ class TracepointProvider(object):
                     ret[name] += val
         return ret
 
+
 class DebugfsProvider(object):
     """Provides data from the files that KVM creates in the kvm debugfs
     folder."""

@@ -719,6 +730,7 @@ class DebugfsProvider(object):
         except IOError:
             return 0
 
+
 class Stats(object):
     """Manages the data providers and the data they provide.
 

@@ -790,6 +802,7 @@ class Stats(object):
 LABEL_WIDTH = 40
 NUMBER_WIDTH = 10
 
+
 class Tui(object):
     """Instruments curses to draw a nice text ui."""
     def __init__(self, stats):

@@ -859,6 +872,7 @@ class Tui(object):
                            len('Current'), 'Current')
         row = 3
         stats = self.stats.get()
+
         def sortkey(x):
             if stats[x][1]:
                 return (-stats[x][1], -stats[x][0])

@@ -966,6 +980,7 @@ class Tui(object):
             except curses.error:
                 continue
 
+
 def batch(stats):
     """Prints statistics in a key, value format."""
     try:

@@ -978,13 +993,16 @@ def batch(stats):
     except KeyboardInterrupt:
         pass
 
+
 def log(stats):
     """Prints statistics as reiterating key block, multiple value blocks."""
     keys = sorted(stats.get().iterkeys())
+
     def banner():
         for k in keys:
             print '%s' % k,
         print
+
     def statline():
         s = stats.get()
         for k in keys:

@@ -1002,6 +1020,7 @@ def log(stats):
         except KeyboardInterrupt:
             break
 
+
 def get_options():
     """Returns processed program arguments."""
     description_text = """

@@ -1072,6 +1091,7 @@ Requirements:
     (options, _) = optparser.parse_args(sys.argv)
     return options
 
+
 def get_providers(options):
     """Returns a list of data providers depending on the passed options."""
     providers = []

@@ -1085,6 +1105,7 @@ def get_providers(options):
 
     return providers
 
+
 def check_access(options):
     """Exits if the current user can't access all needed directories."""
     if not os.path.exists('/sys/kernel/debug'):

@@ -1114,6 +1135,7 @@ def check_access(options):
 
     return options
 
+
 def main():
     options = get_options()
     options = check_access(options)

index 5c4f248..3e60d93 100755
@@ -801,6 +801,8 @@ class Stats(object):
 
 LABEL_WIDTH = 40
 NUMBER_WIDTH = 10
+DELAY_INITIAL = 0.25
+DELAY_REGULAR = 3.0
 
 
 class Tui(object):

@@ -856,13 +858,14 @@ class Tui(object):
         """Propagates pid selection to stats object."""
         self.stats.pid_filter = pid
 
-    def refresh(self, sleeptime):
-        """Refreshes on-screen data."""
+    def refresh_header(self, pid=None):
+        """Refreshes the header."""
+        if pid is None:
+            pid = self.stats.pid_filter
         self.screen.erase()
-        if self.stats.pid_filter > 0:
+        if pid > 0:
             self.screen.addstr(0, 0, 'kvm statistics - pid {0}'
-                               .format(self.stats.pid_filter),
-                               curses.A_BOLD)
+                               .format(pid), curses.A_BOLD)
         else:
             self.screen.addstr(0, 0, 'kvm statistics - summary', curses.A_BOLD)
         self.screen.addstr(2, 1, 'Event')

@@ -870,7 +873,13 @@ class Tui(object):
                            len('Total'), 'Total')
         self.screen.addstr(2, 1 + LABEL_WIDTH + NUMBER_WIDTH + 8 -
                            len('Current'), 'Current')
+        self.screen.addstr(4, 1, 'Collecting data...')
+        self.screen.refresh()
+
+    def refresh_body(self, sleeptime):
         row = 3
+        self.screen.move(row, 0)
+        self.screen.clrtobot()
         stats = self.stats.get()
 
         def sortkey(x):

@@ -914,10 +923,12 @@ class Tui(object):
             regex = self.screen.getstr()
             curses.noecho()
             if len(regex) == 0:
+                self.refresh_header()
                 return
             try:
                 re.compile(regex)
                 self.stats.fields_filter = regex
+                self.refresh_header()
                 return
             except re.error:
                 continue

@@ -944,37 +955,38 @@ class Tui(object):
 
             try:
                 pid = int(pid)
-
-                if pid == 0:
-                    self.update_pid(pid)
-                    break
-                else:
-                    if not os.path.isdir(os.path.join('/proc/', str(pid))):
-                        continue
-                    else:
-                        self.update_pid(pid)
-                        break
+                if pid != 0 and not os.path.isdir(os.path.join('/proc/',
+                                                               str(pid))):
+                    continue
+                self.refresh_header(pid)
+                self.update_pid(pid)
+                break
 
             except ValueError:
                 continue
 
     def show_stats(self):
         """Refreshes the screen and processes user input."""
-        sleeptime = 0.25
+        sleeptime = DELAY_INITIAL
+        self.refresh_header()
         while True:
-            self.refresh(sleeptime)
+            self.refresh_body(sleeptime)
             curses.halfdelay(int(sleeptime * 10))
-            sleeptime = 3.0
+            sleeptime = DELAY_REGULAR
             try:
                 char = self.screen.getkey()
                 if char == 'x':
+                    self.refresh_header()
                     self.update_drilldown()
+                    sleeptime = DELAY_INITIAL
                 if char == 'q':
                     break
                 if char == 'f':
                     self.show_filter_selection()
+                    sleeptime = DELAY_INITIAL
                 if char == 'p':
                     self.show_vm_selection()
+                    sleeptime = DELAY_INITIAL
             except KeyboardInterrupt:
                 break
             except curses.error:

index 3e60d93..aca8508 100755
@@ -1052,6 +1052,13 @@ Requirements:
   CAP_SYS_ADMIN and perf events are used.
 - CAP_SYS_RESOURCE if the hard limit is not high enough to allow
   the large number of files that are possibly opened.
+
+Interactive Commands:
+   f     filter by regular expression
+   p     filter by PID
+   q     quit
+   x     toggle reporting of stats for individual child trace events
+Press any other key to refresh statistics immediately.
 """
 
     class PlainHelpFormatter(optparse.IndentedHelpFormatter):

index b92a153..077bcc7 100644
@@ -18,11 +18,27 @@ state transitions such as guest mode entry and exit.
 This tool is useful for observing guest behavior from the host perspective.
 Often conclusions about performance or buggy behavior can be drawn from the
 output.
+While running in regular mode, use any of the keys listed in section
+'Interactive Commands' below.
+Use batch and logging modes for scripting purposes.
 
 The set of KVM kernel module trace events may be specific to the kernel version
 or architecture.  It is best to check the KVM kernel module source code for the
 meaning of events.
 
+INTERACTIVE COMMANDS
+--------------------
+[horizontal]
+*f*::	filter by regular expression
+
+*p*::	filter by PID
+
+*q*::	quit
+
+*x*::	toggle reporting of stats for child trace events
+
+Press any other key to refresh statistics immediately.
+
 OPTIONS
 -------
 -1::

index aca8508..95ffa9a 100755
@@ -320,6 +320,37 @@ def parse_int_list(list_string):
     return integers
 
 
+def get_gname_from_pid(pid):
+    """Returns the guest name for a QEMU process pid.
+
+    Extracts the guest name from the QEMU comma line by processing the '-name'
+    option. Will also handle names specified out of sequence.
+
+    """
+    name = ''
+    try:
+        line = open('/proc/{}/cmdline'.format(pid), 'rb').read().split('\0')
+        parms = line[line.index('-name') + 1].split(',')
+        while '' in parms:
+            # commas are escaped (i.e. ',,'), hence e.g. 'foo,bar' results in
+            # ['foo', '', 'bar'], which we revert here
+            idx = parms.index('')
+            parms[idx - 1] += ',' + parms[idx + 1]
+            del parms[idx:idx+2]
+        # the '-name' switch allows for two ways to specify the guest name,
+        # where the plain name overrides the name specified via 'guest='
+        for arg in parms:
+            if '=' not in arg:
+                name = arg
+                break
+            if arg[:6] == 'guest=':
+                name = arg[6:]
+    except (ValueError, IOError, IndexError):
+        pass
+
+    return name
+
+
 def get_online_cpus():
     """Returns a list of cpu id integers."""
     with open('/sys/devices/system/cpu/online') as cpu_list:

@@ -803,6 +834,7 @@ LABEL_WIDTH = 40
 NUMBER_WIDTH = 10
 DELAY_INITIAL = 0.25
 DELAY_REGULAR = 3.0
+MAX_GUEST_NAME_LEN = 48
 
 
 class Tui(object):

@@ -863,9 +895,14 @@ class Tui(object):
         if pid is None:
             pid = self.stats.pid_filter
         self.screen.erase()
+        gname = get_gname_from_pid(pid)
+        if gname:
+            gname = ('({})'.format(gname[:MAX_GUEST_NAME_LEN] + '...'
+                                   if len(gname) > MAX_GUEST_NAME_LEN
+                                   else gname))
         if pid > 0:
-            self.screen.addstr(0, 0, 'kvm statistics - pid {0}'
-                               .format(pid), curses.A_BOLD)
+            self.screen.addstr(0, 0, 'kvm statistics - pid {0} {1}'
+                               .format(pid, gname), curses.A_BOLD)
         else:
             self.screen.addstr(0, 0, 'kvm statistics - summary', curses.A_BOLD)
         self.screen.addstr(2, 1, 'Event')

index 95ffa9a..9e9eb98 100755
@@ -991,10 +991,13 @@ class Tui(object):
             curses.noecho()
 
             try:
-                pid = int(pid)
-                if pid != 0 and not os.path.isdir(os.path.join('/proc/',
-                                                               str(pid))):
-                    continue
+                if len(pid) > 0:
+                    pid = int(pid)
+                    if pid != 0 and not os.path.isdir(os.path.join('/proc/',
+                                                                   str(pid))):
+                        continue
+                else:
+                    pid = 0
                 self.refresh_header(pid)
                 self.update_pid(pid)
                 break

index 9e9eb98..ced0cb9 100755
@@ -976,6 +976,7 @@ class Tui(object):
         Asks for a pid until a valid pid or 0 has been entered.
 
         """
+        msg = ''
         while True:
             self.screen.erase()
             self.screen.addstr(0, 0,

@@ -984,6 +985,7 @@ class Tui(object):
             self.screen.addstr(1, 0,
                                'This might limit the shown data to the trace '
                                'statistics.')
+            self.screen.addstr(5, 0, msg)
 
             curses.echo()
             self.screen.addstr(3, 0, "Pid [0 or pid]: ")

@@ -995,6 +997,7 @@ class Tui(object):
                     pid = int(pid)
                     if pid != 0 and not os.path.isdir(os.path.join('/proc/',
                                                                    str(pid))):
+                        msg = '"' + str(pid) + '": Not a running process'
                         continue
                 else:
                     pid = 0

@@ -1003,6 +1006,7 @@ class Tui(object):
                 break
 
             except ValueError:
+                msg = '"' + str(pid) + '": Not a valid pid'
                 continue
 
     def show_stats(self):

index ced0cb9..af70717 100755
@@ -835,6 +835,7 @@ NUMBER_WIDTH = 10
 DELAY_INITIAL = 0.25
 DELAY_REGULAR = 3.0
 MAX_GUEST_NAME_LEN = 48
+MAX_REGEX_LEN = 44
 
 
 class Tui(object):

@@ -905,6 +906,11 @@ class Tui(object):
                                .format(pid, gname), curses.A_BOLD)
         else:
             self.screen.addstr(0, 0, 'kvm statistics - summary', curses.A_BOLD)
+        if self.stats.fields_filter and self.stats.fields_filter != '^[^\(]*$':
+            regex = self.stats.fields_filter
+            if len(regex) > MAX_REGEX_LEN:
+                regex = regex[:MAX_REGEX_LEN] + '...'
+            self.screen.addstr(1, 17, 'regex filter: {0}'.format(regex))
         self.screen.addstr(2, 1, 'Event')
         self.screen.addstr(2, 1 + LABEL_WIDTH + NUMBER_WIDTH -
                            len('Total'), 'Total')

index af70717..f2a868b 100755
@@ -966,6 +966,7 @@ class Tui(object):
             regex = self.screen.getstr()
             curses.noecho()
             if len(regex) == 0:
+                self.stats.fields_filter = r'^[^\(]*$'
                 self.refresh_header()
                 return
             try:

index f2a868b..f263312 100755
@@ -30,6 +30,7 @@ import fcntl
 import resource
 import struct
 import re
+import subprocess
 from collections import defaultdict
 
 VMX_EXIT_REASONS = {

@@ -320,6 +321,30 @@ def parse_int_list(list_string):
     return integers
 
 
+def get_pid_from_gname(gname):
+    """Fuzzy function to convert guest name to QEMU process pid.
+
+    Returns a list of potential pids, can be empty if no match found.
+    Throws an exception on processing errors.
+
+    """
+    pids = []
+    try:
+        child = subprocess.Popen(['ps', '-A', '--format', 'pid,args'],
+                                 stdout=subprocess.PIPE)
+    except:
+        raise Exception
+    for line in child.stdout:
+        line = line.lstrip().split(' ', 1)
+        # perform a sanity check before calling the more expensive
+        # function to possibly extract the guest name
+        if ' -name ' in line[1] and gname == get_gname_from_pid(line[0]):
+            pids.append(int(line[0]))
+    child.stdout.close()
+
+    return pids
+
+
 def get_gname_from_pid(pid):
     """Returns the guest name for a QEMU process pid.
 

@@ -977,7 +1002,7 @@ class Tui(object):
             except re.error:
                 continue
 
-    def show_vm_selection(self):
+    def show_vm_selection_by_pid(self):
         """Draws PID selection mask.
 
         Asks for a pid until a valid pid or 0 has been entered.

@@ -1016,6 +1041,50 @@ class Tui(object):
                 msg = '"' + str(pid) + '": Not a valid pid'
                 continue
 
+    def show_vm_selection_by_guest_name(self):
+        """Draws guest selection mask.
+
+        Asks for a guest name until a valid guest name or '' is entered.
+
+        """
+        msg = ''
+        while True:
+            self.screen.erase()
+            self.screen.addstr(0, 0,
+                               'Show statistics for specific guest.',
+                               curses.A_BOLD)
+            self.screen.addstr(1, 0,
+                               'This might limit the shown data to the trace '
+                               'statistics.')
+            self.screen.addstr(5, 0, msg)
+            curses.echo()
+            self.screen.addstr(3, 0, "Guest [ENTER or guest]: ")
+            gname = self.screen.getstr()
+            curses.noecho()
+
+            if not gname:
+                self.refresh_header(0)
+                self.update_pid(0)
+                break
+            else:
+                pids = []
+                try:
+                    pids = get_pid_from_gname(gname)
+                except:
+                    msg = '"' + gname + '": Internal error while searching, ' \
+                          'use pid filter instead'
+                    continue
+                if len(pids) == 0:
+                    msg = '"' + gname + '": Not an active guest'
+                    continue
+                if len(pids) > 1:
+                    msg = '"' + gname + '": Multiple matches found, use pid ' \
+                          'filter instead'
+                    continue
+                self.refresh_header(pids[0])
+                self.update_pid(pids[0])
+                break
+
     def show_stats(self):
         """Refreshes the screen and processes user input."""
         sleeptime = DELAY_INITIAL

@@ -1035,8 +1104,11 @@ class Tui(object):
                 if char == 'f':
                     self.show_filter_selection()
                     sleeptime = DELAY_INITIAL
+                if char == 'g':
+                    self.show_vm_selection_by_guest_name()
+                    sleeptime = DELAY_INITIAL
                 if char == 'p':
-                    self.show_vm_selection()
+                    self.show_vm_selection_by_pid()
                     sleeptime = DELAY_INITIAL
             except KeyboardInterrupt:
                 break

@@ -1106,6 +1178,7 @@ Requirements:
 
 Interactive Commands:
    f     filter by regular expression
+   g     filter by guest name
    p     filter by PID
    q     quit
    x     toggle reporting of stats for individual child trace events

@@ -1119,6 +1192,22 @@ Press any other key to refresh statistics immediately.
             else:
                 return ""
 
+    def cb_guest_to_pid(option, opt, val, parser):
+        try:
+            pids = get_pid_from_gname(val)
+        except:
+            raise optparse.OptionValueError('Error while searching for guest '
+                                            '"{}", use "-p" to specify a pid '
+                                            'instead'.format(val))
+        if len(pids) == 0:
+            raise optparse.OptionValueError('No guest by the name "{}" '
+                                            'found'.format(val))
+        if len(pids) > 1:
+            raise optparse.OptionValueError('Multiple processes found (pids: '
+                                            '{}) - use "-p" to specify a pid '
+                                            'instead'.format(" ".join(pids)))
+        parser.values.pid = pids[0]
+
     optparser = optparse.OptionParser(description=description_text,
                                       formatter=PlainHelpFormatter())
     optparser.add_option('-1', '--once', '--batch',

@@ -1158,6 +1247,14 @@ Press any other key to refresh statistics immediately.
                          dest='pid',
                          help='restrict statistics to pid',
                          )
+    optparser.add_option('-g', '--guest',
+                         action='callback',
+                         type='string',
+                         dest='pid',
+                         metavar='GUEST',
+                         help='restrict statistics to guest by name',
+                         callback=cb_guest_to_pid,
+                         )
     (options, _) = optparser.parse_args(sys.argv)
     return options
 

index 077bcc7..35587c3 100644
@@ -31,6 +31,8 @@ INTERACTIVE COMMANDS
 [horizontal]
 *f*::	filter by regular expression
 
+*g*::	filter by guest name
+
 *p*::	filter by PID
 
 *q*::	quit

@@ -62,6 +64,10 @@ OPTIONS
 --pid=<pid>::
 	limit statistics to one virtual machine (pid)
 
+-g<guest>::
+--guest=<guest_name>::
+	limit statistics to one virtual machine (guest name)
+
 -f<fields>::
 --fields=<fields>::
 	fields to display (regex)

index f263312..676a92a 100755
@@ -861,6 +861,7 @@ DELAY_INITIAL = 0.25
 DELAY_REGULAR = 3.0
 MAX_GUEST_NAME_LEN = 48
 MAX_REGEX_LEN = 44
+DEFAULT_REGEX = r'^[^\(]*$'
 
 
 class Tui(object):

@@ -907,9 +908,9 @@ class Tui(object):
     def update_drilldown(self):
         """Sets or removes a filter that only allows fields without braces."""
         if not self.stats.fields_filter:
-            self.stats.fields_filter = r'^[^\(]*$'
+            self.stats.fields_filter = DEFAULT_REGEX
 
-        elif self.stats.fields_filter == r'^[^\(]*$':
+        elif self.stats.fields_filter == DEFAULT_REGEX:
             self.stats.fields_filter = None
 
     def update_pid(self, pid):

@@ -931,7 +932,8 @@ class Tui(object):
                                .format(pid, gname), curses.A_BOLD)
         else:
             self.screen.addstr(0, 0, 'kvm statistics - summary', curses.A_BOLD)
-        if self.stats.fields_filter and self.stats.fields_filter != '^[^\(]*$':
+        if self.stats.fields_filter and self.stats.fields_filter \
+           != DEFAULT_REGEX:
             regex = self.stats.fields_filter
             if len(regex) > MAX_REGEX_LEN:
                 regex = regex[:MAX_REGEX_LEN] + '...'

@@ -991,7 +993,7 @@ class Tui(object):
             regex = self.screen.getstr()
             curses.noecho()
             if len(regex) == 0:
-                self.stats.fields_filter = r'^[^\(]*$'
+                self.stats.fields_filter = DEFAULT_REGEX
                 self.refresh_header()
                 return
             try:

@@ -1101,6 +1103,11 @@ class Tui(object):
                     sleeptime = DELAY_INITIAL
                 if char == 'q':
                     break
+                if char == 'c':
+                    self.stats.fields_filter = DEFAULT_REGEX
+                    self.refresh_header(0)
+                    self.update_pid(0)
+                    sleeptime = DELAY_INITIAL
                 if char == 'f':
                     self.show_filter_selection()
                     sleeptime = DELAY_INITIAL

@@ -1177,6 +1184,7 @@ Requirements:
   the large number of files that are possibly opened.
 
 Interactive Commands:
+   c     clear filter
    f     filter by regular expression
    g     filter by guest name
    p     filter by PID

index 35587c3..c3ab6a2 100644
@@ -29,6 +29,8 @@ meaning of events.
 INTERACTIVE COMMANDS
 --------------------
 [horizontal]
+*c*::	clear filter
+
 *f*::	filter by regular expression
 
 *g*::	filter by guest name

index 676a92a..f8c48f8 100755
@@ -716,15 +716,23 @@ class TracepointProvider(object):
                     ret[name] += val
         return ret
 
+    def reset(self):
+        """Reset all field counters"""
+        for group in self.group_leaders:
+            for event in group.events:
+                event.reset()
+
 
 class DebugfsProvider(object):
     """Provides data from the files that KVM creates in the kvm debugfs
     folder."""
     def __init__(self):
         self._fields = self.get_available_fields()
+        self._baseline = {}
         self._pid = 0
         self.do_read = True
         self.paths = []
+        self.reset()
 
     def get_available_fields(self):
         """"Returns a list of available fields.

@@ -741,6 +749,7 @@ class DebugfsProvider(object):
     @fields.setter
     def fields(self, fields):
         self._fields = fields
+        self.reset()
 
     @property
     def pid(self):

@@ -758,10 +767,11 @@ class DebugfsProvider(object):
             self.paths = filter(lambda x: "{}-".format(pid) in x, vms)
 
         else:
-            self.paths = ['']
+            self.paths = []
             self.do_read = True
+        self.reset()
 
-    def read(self):
+    def read(self, reset=0):
         """Returns a dict with format:'file name / field -> current value'."""
         results = {}
 

@@ -769,10 +779,22 @@ class DebugfsProvider(object):
         if not self.do_read:
             return results
 
-        for path in self.paths:
+        paths = self.paths
+        if self._pid == 0:
+            paths = []
+            for entry in os.walk(PATH_DEBUGFS_KVM):
+                for dir in entry[1]:
+                    paths.append(dir)
+        for path in paths:
             for field in self._fields:
-                results[field] = results.get(field, 0) \
-                                 + self.read_field(field, path)
+                value = self.read_field(field, path)
+                key = path + field
+                if reset:
+                    self._baseline[key] = value
+                if self._baseline.get(key, -1) == -1:
+                    self._baseline[key] = value
+                results[field] = (results.get(field, 0) + value -
+                                  self._baseline.get(key, 0))
 
         return results
 

@@ -786,6 +808,11 @@ class DebugfsProvider(object):
         except IOError:
             return 0
 
+    def reset(self):
+        """Reset field counters"""
+        self._baseline = {}
+        self.read(1)
+
 
 class Stats(object):
     """Manages the data providers and the data they provide.

@@ -822,14 +849,20 @@ class Stats(object):
         for provider in self.providers:
             provider.pid = self._pid_filter
 
+    def reset(self):
+        self.values = {}
+        for provider in self.providers:
+            provider.reset()
+
     @property
     def fields_filter(self):
         return self._fields_filter
 
     @fields_filter.setter
     def fields_filter(self, fields_filter):
-        self._fields_filter = fields_filter
-        self.update_provider_filters()
+        if fields_filter != self._fields_filter:
+            self._fields_filter = fields_filter
+            self.update_provider_filters()
 
     @property
     def pid_filter(self):

@@ -837,9 +870,10 @@ class Stats(object):
 
     @pid_filter.setter
     def pid_filter(self, pid):
-        self._pid_filter = pid
-        self.values = {}
-        self.update_provider_pid()
+        if pid != self._pid_filter:
+            self._pid_filter = pid
+            self.values = {}
+            self.update_provider_pid()
 
     def get(self):
         """Returns a dict with field -> (value, delta to last value) of all

@@ -847,11 +881,9 @@ class Stats(object):
         for provider in self.providers:
             new = provider.read()
             for key in provider.fields:
-                oldval = self.values.get(key, (0, 0))
+                oldval = self.values.get(key, (0, 0))[0]
                 newval = new.get(key, 0)
-                newdelta = None
-                if oldval is not None:
-                    newdelta = newval - oldval[0]
+                newdelta = newval - oldval
                 self.values[key] = (newval, newdelta)
         return self.values
 

@@ -1117,6 +1149,10 @@ class Tui(object):
                 if char == 'p':
                     self.show_vm_selection_by_pid()
                     sleeptime = DELAY_INITIAL
+                if char == 'r':
+                    self.refresh_header()
+                    self.stats.reset()
+                    sleeptime = DELAY_INITIAL
             except KeyboardInterrupt:
                 break
             except curses.error:

@@ -1190,6 +1226,7 @@ Interactive Commands:
    p     filter by PID
    q     quit
    x     toggle reporting of stats for individual child trace events
+   r     reset stats
 Press any other key to refresh statistics immediately.
 """
 

index c3ab6a2..109431b 100644
@@ -39,6 +39,8 @@ INTERACTIVE COMMANDS
 
 *q*::	quit
 
+*r*::	reset stats
+
 *x*::	toggle reporting of stats for child trace events
 
 Press any other key to refresh statistics immediately.

index f8c48f8..8f74ed8 100755
@@ -973,7 +973,9 @@ class Tui(object):
         self.screen.addstr(2, 1, 'Event')
         self.screen.addstr(2, 1 + LABEL_WIDTH + NUMBER_WIDTH -
                            len('Total'), 'Total')
-        self.screen.addstr(2, 1 + LABEL_WIDTH + NUMBER_WIDTH + 8 -
+        self.screen.addstr(2, 1 + LABEL_WIDTH + NUMBER_WIDTH + 7 -
+                           len('%Total'), '%Total')
+        self.screen.addstr(2, 1 + LABEL_WIDTH + NUMBER_WIDTH + 7 + 8 -
                            len('Current'), 'Current')
         self.screen.addstr(4, 1, 'Collecting data...')
         self.screen.refresh()

@@ -989,6 +991,9 @@ class Tui(object):
                 return (-stats[x][1], -stats[x][0])
             else:
                 return (0, -stats[x][0])
+        total = 0.
+        for val in stats.values():
+            total += val[0]
         for key in sorted(stats.keys(), key=sortkey):
 
             if row >= self.screen.getmaxyx()[0]:

@@ -1001,6 +1006,8 @@ class Tui(object):
             col += LABEL_WIDTH
             self.screen.addstr(row, col, '%10d' % (values[0],))
             col += NUMBER_WIDTH
+            self.screen.addstr(row, col, '%7.1f' % (values[0] * 100 / total,))
+            col += 7
             if values[1] is not None:
                 self.screen.addstr(row, col, '%8d' % (values[1] / sleeptime,))
             row += 1