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Re: [PATCH] perf tools: Fix gaps propagating maps

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On 04/09/15 16:28, Arnaldo Carvalho de Melo wrote:
> Em Fri, Sep 04, 2015 at 03:15:54PM +0300, Adrian Hunter escreveu:
>> A perf_evsel is a selected event containing the perf_event_attr
>> that is passed to perf_event_open().  A perf_evlist is a collection
>> of perf_evsel's.  A perf_evlist also has lists of cpus and threads
>> (pids) on which to open the event.  These lists are called 'maps'
>> and this patch is about how those 'maps' are propagated from the
>>> perf_evlist to the perf_evsels.
> 
> Can't this be broken up in multiple patches, for instance this:

Ok, might not be until next week though.

> 
>  int perf_evlist__create_maps(struct perf_evlist *evlist, struct
>  target *target)
>  {
> +     if (evlist->threads || evlist->cpus)
> +             return -1;
> +

Or you could just drop that chunk.

> 
> Looks like a fix that could be separated. Also FOO__propagate(.., false)
> to do the opposite of propagate seems confusing, how about
> FOO__unpropagate() if that verb exists? :-)

Ok

> 
> 
> Also, when unpropagating, you do:
> 
>              if (evsel->cpus == evlist->cpus) {
>                      cpu_map__put(evsel->cpus);
>                      evsel->cpus = NULL;
>              }
> 
> What if the PMU code _set_ it to the same cpus as in evlist->cpus, but
> now we're unpropagating to set to another CPU, in this case we will be
> changing the PMU setting with a new one. I.e. when a PMU sets it it
> should be sticky, no?

We are comparing the pointer, so that won't happen unless the PMU actually
does evsel->cpus = evlist->cpus which seems unlikely.

> 
> I.e. we would have to know, in the evsel, if evsel->cpus was set by the
> PMU or any other future entity expecting this behaviour, so that we
> don't touch it, i.e. testing (evsel->cpus != evlist->cpus) when
> unpropagating doesn't seem to cut, right?

I think the pointer comparison covers that. i.e. the pointers won't be the
same even if the cpus are.

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Thread

[PATCH 1/1] perf,tools: open event on evsel cpus and threads kan.liang@intel.com - 2015-08-21 15:40 +0200
  Re: [PATCH 1/1] perf,tools: open event on evsel cpus and threads Jiri Olsa <jolsa@redhat.com> - 2015-08-21 16:00 +0200
    Re: [PATCH 1/1] perf,tools: open event on evsel cpus and threads Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-08-31 22:40 +0200
      RE: [PATCH 1/1] perf,tools: open event on evsel cpus and threads "Liang, Kan" <kan.liang@intel.com> - 2015-08-31 23:10 +0200
        Re: [PATCH 1/1] perf,tools: open event on evsel cpus and threads Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-08-31 23:20 +0200
          RE: [PATCH 1/1] perf,tools: open event on evsel cpus and threads "Liang, Kan" <kan.liang@intel.com> - 2015-08-31 23:30 +0200
            Re: [PATCH 1/1] perf,tools: open event on evsel cpus and threads Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-08-31 23:40 +0200
  [tip:perf/urgent] perf evlist:   Open event on evsel cpus and threads tip-bot for Kan Liang <tipbot@zytor.com> - 2015-09-01 10:40 +0200
    Re: [tip:perf/urgent] perf evlist: Open event on evsel cpus and  threads Adrian Hunter <adrian.hunter@intel.com> - 2015-09-03 15:40 +0200
      Re: [tip:perf/urgent] perf evlist: Open event on evsel cpus and  threads Arnaldo Carvalho de Melo <acme@redhat.com> - 2015-09-03 17:30 +0200
        Re: [tip:perf/urgent] perf evlist: Open event on evsel cpus and  threads Adrian Hunter <adrian.hunter@intel.com> - 2015-09-03 18:30 +0200
          Re: [tip:perf/urgent] perf evlist: Open event on evsel cpus and  threads Arnaldo Carvalho de Melo <acme@redhat.com> - 2015-09-03 18:50 +0200
            Re: [tip:perf/urgent] perf evlist: Open event on evsel cpus and  threads Jiri Olsa <jolsa@redhat.com> - 2015-09-03 20:20 +0200
              Re: [tip:perf/urgent] perf evlist: Open event on evsel cpus and  threads Adrian Hunter <adrian.hunter@intel.com> - 2015-09-03 20:40 +0200
                Re: [tip:perf/urgent] perf evlist: Open event on evsel cpus and  threads Jiri Olsa <jolsa@redhat.com> - 2015-09-03 21:10 +0200
              Re: [tip:perf/urgent] perf evlist: Open event on evsel cpus and  threads Arnaldo Carvalho de Melo <acme@redhat.com> - 2015-09-03 22:50 +0200
                Re: [tip:perf/urgent] perf evlist: Open event on evsel cpus and  threads Jiri Olsa <jolsa@redhat.com> - 2015-09-04 09:10 +0200
                Re: [tip:perf/urgent] perf evlist: Open event on evsel cpus and  threads Adrian Hunter <adrian.hunter@intel.com> - 2015-09-04 09:20 +0200
                [PATCH] perf tools: Fix gaps propagating maps Adrian Hunter <adrian.hunter@intel.com> - 2015-09-04 14:20 +0200
                Re: [PATCH] perf tools: Fix gaps propagating maps Arnaldo Carvalho de Melo <acme@redhat.com> - 2015-09-04 15:30 +0200
                Re: [PATCH] perf tools: Fix gaps propagating maps Adrian Hunter <adrian.hunter@intel.com> - 2015-09-04 15:50 +0200
                Re: [PATCH] perf tools: Fix gaps propagating maps Arnaldo Carvalho de Melo <acme@redhat.com> - 2015-09-04 16:50 +0200

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