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tools/kvm_stat: simplify initializers

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Simplify a couple of initialization routines:
* TracepointProvider and DebugfsProvider: Pass pid into __init__() instead
  of switching to the requested value in an extra call after initializing
  to the default first.
* Pass a single options object into Stats.__init__(), delaying options
  evaluation accordingly, instead of evaluating options first and passing
  several parts of the options object to Stats.__init__() individually.
* Eliminate Stats.update_provider_pid(), since this 2-line function is now
  used in a single place only.
* Remove extra call to update_drilldown() in Tui.__init__() by getting the
  value of options.fields right initially when parsing options.
* Simplify get_providers() logic.
* Avoid duplicate fields initialization by handling it once in the
  providers' __init__() methods.

Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Stefan Raspl 2017-06-07 21:08:32 +02:00 committed by Paolo Bonzini
parent 5e3823a49c
commit c469117df0
1 changed files with 36 additions and 38 deletions
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74
tools/kvm/kvm_stat/kvm_stat
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@ -295,6 +295,13 @@ class ArchS390(Arch):
ARCH = Arch.get_arch()
def is_field_wanted(fields_filter, field):
"""Indicate whether field is valid according to fields_filter."""
if not fields_filter:
return True
return re.match(fields_filter, field) is not None
def walkdir(path):
"""Returns os.walk() data for specified directory.
@ -581,11 +588,11 @@ class TracepointProvider(object):
Manages the events/groups from which it acquires its data.
"""
def __init__(self):
def __init__(self, pid, fields_filter):
self.group_leaders = []
self.filters = get_filters()
self._fields = self.get_available_fields()
self._pid = 0
self.update_fields(fields_filter)
self.pid = pid
def get_available_fields(self):
"""Returns a list of available event's of format 'event name(filter
@ -613,6 +620,11 @@ class TracepointProvider(object):
fields += extra
return fields
def update_fields(self, fields_filter):
"""Refresh fields, applying fields_filter"""
self._fields = [field for field in self.get_available_fields()
if is_field_wanted(fields_filter, field)]
def setup_traces(self):
"""Creates all event and group objects needed to be able to retrieve
data."""
@ -723,13 +735,12 @@ class TracepointProvider(object):
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()
def __init__(self, pid, fields_filter):
self.update_fields(fields_filter)
self._baseline = {}
self._pid = 0
self.do_read = True
self.paths = []
self.reset()
self.pid = pid
def get_available_fields(self):
""""Returns a list of available fields.
@ -739,6 +750,11 @@ class DebugfsProvider(object):
"""
return walkdir(PATH_DEBUGFS_KVM)[2]
def update_fields(self, fields_filter):
"""Refresh fields, applying fields_filter"""
self._fields = [field for field in self.get_available_fields()
if is_field_wanted(fields_filter, field)]
@property
def fields(self):
return self._fields
@ -754,9 +770,8 @@ class DebugfsProvider(object):
@pid.setter
def pid(self, pid):
self._pid = pid
if pid != 0:
self._pid = pid
vms = walkdir(PATH_DEBUGFS_KVM)[1]
if len(vms) == 0:
self.do_read = False
@ -818,33 +833,19 @@ class Stats(object):
provider data.
"""
def __init__(self, providers, pid, fields=None):
self.providers = providers
self._pid_filter = pid
self._fields_filter = fields
def __init__(self, options):
self.providers = get_providers(options)
self._pid_filter = options.pid
self._fields_filter = options.fields
self.values = {}
self.update_provider_pid()
self.update_provider_filters()
def update_provider_filters(self):
"""Propagates fields filters to providers."""
def wanted(key):
if not self._fields_filter:
return True
return re.match(self._fields_filter, key) is not None
# As we reset the counters when updating the fields we can
# also clear the cache of old values.
self.values = {}
for provider in self.providers:
provider_fields = [key for key in provider.get_available_fields()
if wanted(key)]
provider.fields = provider_fields
def update_provider_pid(self):
"""Propagates pid filters to providers."""
for provider in self.providers:
provider.pid = self._pid_filter
provider.update_fields(self._fields_filter)
def reset(self):
self.values = {}
@ -870,7 +871,8 @@ class Stats(object):
if pid != self._pid_filter:
self._pid_filter = pid
self.values = {}
self.update_provider_pid()
for provider in self.providers:
provider.pid = self._pid_filter
def get(self):
"""Returns a dict with field -> (value, delta to last value) of all
@ -896,7 +898,6 @@ class Tui(object):
def __init__(self, stats):
self.stats = stats
self.screen = None
self.update_drilldown()
def __enter__(self):
"""Initialises curses for later use. Based on curses.wrapper
@ -1270,7 +1271,7 @@ Press any other key to refresh statistics immediately.
)
optparser.add_option('-f', '--fields',
action='store',
default=None,
default=DEFAULT_REGEX,
dest='fields',
help='fields to display (regex)',
)
@ -1297,12 +1298,10 @@ def get_providers(options):
"""Returns a list of data providers depending on the passed options."""
providers = []
if options.tracepoints:
providers.append(TracepointProvider())
if options.debugfs:
providers.append(DebugfsProvider())
if len(providers) == 0:
providers.append(TracepointProvider())
providers.append(DebugfsProvider(options.pid, options.fields))
if options.tracepoints or not providers:
providers.append(TracepointProvider(options.pid, options.fields))
return providers
@ -1347,8 +1346,7 @@ def main():
sys.stderr.write('Did you use a (unsupported) tid instead of a pid?\n')
sys.exit('Specified pid does not exist.')
providers = get_providers(options)
stats = Stats(providers, options.pid, fields=options.fields)
stats = Stats(options)
if options.log:
log(stats)