On 21/04/19 15:26, Stefan Raspl wrote:
> From: Stefan Raspl <stefan.raspl@xxxxxxxxxx>
>
> The fields filter would not work with child fields, as the respective
> parents would not be included. No parents displayed == no childs displayed.
> To reproduce, run on s390 (would work on other platforms, too, but would
> require a different filter name):
> - Run 'kvm_stat -d'
> - Press 'f'
> - Enter 'instruct'
> Notice that events like instruction_diag_44 or instruction_diag_500 are not
> displayed - the output remains empty.
> With this patch, we will filter by matching events and their parents.
> However, consider the following example where we filter by
> instruction_diag_44:
>
> kvm statistics - summary
> regex filter: instruction_diag_44
> Event Total %Total CurAvg/s
> exit_instruction 276 100.0 12
> instruction_diag_44 256 92.8 11
> Total 276 12
>
> Note that the parent ('exit_instruction') displays the total events, but
> the childs listed do not match its total (256 instead of 276). This is
> intended (since we're filtering all but one child), but might be confusing
> on first sight.
>
> Signed-off-by: Stefan Raspl <raspl@xxxxxxxxxxxxx>
> ---
> tools/kvm/kvm_stat/kvm_stat | 16 ++++++++++++----
> tools/kvm/kvm_stat/kvm_stat.txt | 2 ++
> 2 files changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/tools/kvm/kvm_stat/kvm_stat b/tools/kvm/kvm_stat/kvm_stat
> index 2ed395b817cb..bc508dae286c 100755
> --- a/tools/kvm/kvm_stat/kvm_stat
> +++ b/tools/kvm/kvm_stat/kvm_stat
> @@ -575,8 +575,12 @@ class TracepointProvider(Provider):
> def update_fields(self, fields_filter):
> """Refresh fields, applying fields_filter"""
> self.fields = [field for field in self._get_available_fields()
> - if self.is_field_wanted(fields_filter, field) or
> - ARCH.tracepoint_is_child(field)]
> + if self.is_field_wanted(fields_filter, field)]
> + # add parents for child fields - otherwise we won't see any output!
> + for field in self._fields:
> + parent = ARCH.tracepoint_is_child(field)
> + if (parent and parent not in self._fields):
> + self.fields.append(parent)
>
> @staticmethod
> def _get_online_cpus():
> @@ -735,8 +739,12 @@ class DebugfsProvider(Provider):
> def update_fields(self, fields_filter):
> """Refresh fields, applying fields_filter"""
> self._fields = [field for field in self._get_available_fields()
> - if self.is_field_wanted(fields_filter, field) or
> - ARCH.debugfs_is_child(field)]
> + if self.is_field_wanted(fields_filter, field)]
> + # add parents for child fields - otherwise we won't see any output!
> + for field in self._fields:
> + parent = ARCH.debugfs_is_child(field)
> + if (parent and parent not in self._fields):
> + self.fields.append(parent)
>
> @property
> def fields(self):
> diff --git a/tools/kvm/kvm_stat/kvm_stat.txt b/tools/kvm/kvm_stat/kvm_stat.txt
> index 0811d860fe75..c057ba52364e 100644
> --- a/tools/kvm/kvm_stat/kvm_stat.txt
> +++ b/tools/kvm/kvm_stat/kvm_stat.txt
> @@ -34,6 +34,8 @@ INTERACTIVE COMMANDS
> *c*:: clear filter
>
> *f*:: filter by regular expression
> + :: *Note*: Child events pull in their parents, and parents' stats summarize
> + all child events, not just the filtered ones
>
> *g*:: filter by guest name/PID
>
>
Queued, thanks.
Paolo
