• Arnaldo Carvalho de Melo's avatar
    perf hists browser: Take the --comm, --dsos, etc filters into account · 6bf9964d
    Arnaldo Carvalho de Melo authored
    commit 9c0fa8dd upstream.
    
    At some point:
    
      commit 2c86c7ca
      Author: Namhyung Kim <namhyung@kernel.org>
      Date:   Mon Mar 17 18:18:54 2014 -0300
    
        perf report: Merge al->filtered with hist_entry->filtered
    
    We stopped dropping samples for things filtered via the --comms, --dsos,
    --symbols, etc, i.e. things marked as filtered in the symbol resolution
    routines (thread__find_addr_map(), perf_event__preprocess_sample(),
    etc).
    
    But then, in:
    
      commit 268397cb
      Author: Namhyung Kim <namhyung@kernel.org>
      Date:   Tue Apr 22 14:49:31 2014 +0900
    
        perf top/tui: Update nr_entries properly after a filter is applied
    
    We don't take into account entries that were filtered in
    perf_event__preprocess_sample() and friends, which leads to
    inconsistency in the browser seek routines, that expects the number of
    hist_entry->filtered entries to match what it thinks is the number of
    unfiltered, browsable entries.
    
    So, for instance, when we do:
    
      perf top --symbols ___non_existent_symbol___
    
    the hist_browser__nr_entries() routine thinks there are no filters in
    place, uses the hists->nr_entries but all entries are filtered, leading
    to a segfault.
    
    Tested with:
    
       perf top --symbols malloc,free --percentage=relative
    
    Freezing, by pressing 'f', at any time and doing the math on the
    percentages ends up with 100%, ditto for:
    
       perf top --dsos libpthread-2.20.so,libxul.so --percentage=relative
    
    Both were segfaulting, all fixed now.
    
    More work needed to do away with checking if filters are in place, we
    should just use the nr_non_filtered_samples counter, no need to
    conditionally use it or hists.nr_filter, as what the browser does is
    just show unfiltered stuff. An audit of how it is being accounted is
    needed, this is the minimal fix.
    Reported-by: default avatarMichael Petlan <mpetlan@redhat.com>
    Fixes: 268397cb ("perf top/tui: Update nr_entries properly after a filter is applied")
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Borislav Petkov <bp@suse.de>
    Cc: David Ahern <dsahern@gmail.com>
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Stephane Eranian <eranian@google.com>
    Link: http://lkml.kernel.org/n/tip-6w01d5q97qk0d64kuojme5in@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
    6bf9964d
hists.c 50.4 KB