2017-03-10 13:40+0100, Stefan Raspl:
> 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@xxxxxxxxxxxxxxxxxx>
> Acked-by: Janosch Frank <frankja@xxxxxxxxxxxxxxxxxx>
> ---
> tools/kvm/kvm_stat/kvm_stat | 65 ++++++++++++++++++++++++++++++++---------
> tools/kvm/kvm_stat/kvm_stat.txt | 2 ++
> 2 files changed, 53 insertions(+), 14 deletions(-)
>
> diff --git a/tools/kvm/kvm_stat/kvm_stat b/tools/kvm/kvm_stat/kvm_stat
> index 676a92a..f8c48f8 100755
> --- a/tools/kvm/kvm_stat/kvm_stat
> +++ b/tools/kvm/kvm_stat/kvm_stat
> @@ -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':
Could be turned into elif.
> + 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.
> """
>
> diff --git a/tools/kvm/kvm_stat/kvm_stat.txt b/tools/kvm/kvm_stat/kvm_stat.txt
> index c3ab6a2..109431b 100644
> --- a/tools/kvm/kvm_stat/kvm_stat.txt
> +++ b/tools/kvm/kvm_stat/kvm_stat.txt
> @@ -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.
> --
> 2.8.4
>
