tools/kvm_stat: add interactive command 'r'

Provide an interactive command to reset the tracepoint statistics.
Requires some extra work for debugfs, as the counters cannot be reset.

On the up side, this offers us the opportunity to have debugfs values
reset on startup and whenever a filter is modified, becoming consistent
with the tracepoint provider. As a bonus, 'kvmstat -dt' will now provide
useful output, instead of mixing values in totally different orders of
magnitude.
Furthermore, we avoid unnecessary resets when any of the filters is
"changed" interactively to the previous value.

Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
This commit is contained in:
Stefan Raspl 2017-03-10 13:40:15 +01:00 committed by Paolo Bonzini
parent 4443084fa0
commit 9f114a03c6
2 changed files with 53 additions and 14 deletions

View File

@ -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.
"""

View File

@ -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.