Re: [PATCH 2/3] perf, tool: Enable grouping logic for parsed events

[Namhyung Kim <namhyung@kernel.org>]

On Fri, 29 Jun 2012 11:08:26 +0200, Jiri Olsa wrote:
> This patch adds a functionality that allows to create event groups
> based on the way they are specified on the command line. Adding
> functionality to the '{}' group syntax introduced in earlier patch.
>
> The current '--group/-g' option behaviour remains intact.  If you
> specify it for record/stat/top command, all the specified events
> become members of a single group with the first event as a group
> leader.
>
> With the new '{}' group syntax you can create group like:
>   # perf record -e '{cycles,faults}' ls
>
> resulting in single event group containing 'cycles' and 'faults'
> events, with cycles event as group leader.
>
> All groups are created with regards to threads and cpus. Thus
> recording an event group within a 2 threads on server with
> 4 CPUs will create 8 separate groups.
>
> Examples (first event in brackets is group leader):
>
>   # 1 group (cpu-clock,task-clock)
>   perf record --group -e cpu-clock,task-clock ls
>   perf record -e '{cpu-clock,task-clock}' ls
>
>   # 2 groups (cpu-clock,task-clock) (minor-faults,major-faults)
>   perf record -e '{cpu-clock,task-clock},{minor-faults,major-faults}' ls
>
>   # 1 group (cpu-clock,task-clock,minor-faults,major-faults)
>   perf record --group -e cpu-clock,task-clock -e minor-faults,major-faults ls
>   perf record -e '{cpu-clock,task-clock,minor-faults,major-faults}' ls
>
>   # 2 groups (cpu-clock,task-clock) (minor-faults,major-faults)
>   perf record -e '{cpu-clock,task-clock} -e '{minor-faults,major-faults}' \
>    -e instructions ls
>
>   # 1 group (cpu-clock,task-clock,minor-faults,major-faults,instructions)
>   perf record --group -e cpu-clock,task-clock \
>    -e minor-faults,major-faults -e instructions ls
>   perf record -e '{cpu-clock,task-clock,minor-faults,major-faults,instructions}' ls
>
> It's possible to use standard event modifier for a group, which spans
> over all events in the group and overrides any event modifier settings,
> for example:
>
>   # perf record -r '{faults:k,cache-references}:u'
>
> resulting in ':u' modifier being used for both 'faults' and 'cache-references'
> events, regardless of their modifier setup (':k' for faults event).
>

So the faults event would get only 'u' for the modifier not 'uk', right?

Thanks,
Namhyung