perf hist: Do not delete cumulative caller entries before stat_acc decays

When symbol_conf.cumulate_callchain is enabled (the default in
'perf top -g'), callchain parent/caller entries have he->stat.period == 0
and accumulate their period in he->stat_acc->period.

hists__decay_entry() decays both he->stat.period and he->stat_acc->period,
but only checks if he->stat.period == 0 as the return condition for
deleting the entry in hists__decay_entries(). As a result, every callchain
caller entry with 0 self-period is unconditionally deleted from the
histogram on the first decay pass, destroying its callchain tree while it
still has non-zero cumulative period.

Only mark an entry for deletion in hists__decay_entry() when both
he->stat.period == 0 and (when cumulate_callchain is active)
he->stat_acc->period == 0.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alessio Podda <aleph.pi.gh@gmail.com>
Cc: Alireza Haghdoost <haghdoost@uber.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michael Liang <mliang@purestorage.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shimin Guo <shimin.guo@skydio.com>
Cc: Tanushree Shah <tshah@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

0 files changed, 0 insertions, 0 deletions