Messages in this thread Patch in this message | | | From | Namhyung Kim <> | Subject | [PATCH 10/18] perf report: Cache cumulative callchains | Date | Wed, 18 Dec 2013 14:21:18 +0900 |
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From: Namhyung Kim <namhyung.kim@lge.com>
It is possble that a callchain has cycles or recursive calls. In that case it'll end up having entries more than 100% overhead in the output. In order to prevent such entries, cache each callchain node and skip if same entry already cumulated.
Cc: Arun Sharma <asharma@fb.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- tools/perf/builtin-report.c | 48 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+)
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index 80c774615287..4ec1a090d1a3 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -406,8 +406,27 @@ iter_prepare_cumulative_entry(struct add_entry_iter *iter, struct addr_location *al __maybe_unused, struct perf_sample *sample) { + struct callchain_cursor_node *node; + struct hist_entry **he_cache; + callchain_cursor_commit(&callchain_cursor); + /* + * This is for detecting cycles or recursions so that they're + * cumulated only one time to prevent entries more than 100% + * overhead. + */ + he_cache = malloc(sizeof(*he_cache) * (PERF_MAX_STACK_DEPTH + 1)); + if (he_cache == NULL) + return -ENOMEM; + + iter->priv = he_cache; + iter->curr = 0; + + node = callchain_cursor_current(&callchain_cursor); + if (node == NULL) + return 0; + iter->evsel = evsel; iter->sample = sample; iter->machine = machine; @@ -420,6 +439,7 @@ iter_add_single_cumulative_entry(struct add_entry_iter *iter, { struct perf_evsel *evsel = iter->evsel; struct perf_sample *sample = iter->sample; + struct hist_entry **he_cache = iter->priv; struct hist_entry *he; int err = 0; @@ -429,6 +449,8 @@ iter_add_single_cumulative_entry(struct add_entry_iter *iter, if (he == NULL) return -ENOMEM; + he_cache[iter->curr++] = he; + /* * This is for putting parents upward during output resort iff * only a child gets sampled. See hist_entry__sort_on_period(). @@ -510,8 +532,30 @@ iter_add_next_cumulative_entry(struct add_entry_iter *iter, { struct perf_evsel *evsel = iter->evsel; struct perf_sample *sample = iter->sample; + struct hist_entry **he_cache = iter->priv; struct hist_entry *he; + struct hist_entry he_tmp = { + .cpu = al->cpu, + .thread = al->thread, + .comm = thread__comm(al->thread), + .ip = al->addr, + .ms = { + .map = al->map, + .sym = al->sym, + }, + .parent = iter->parent, + }; int err = 0; + int i; + + /* + * Check if there's duplicate entries in the callchain. + * It's possible that it has cycles or recursive calls. + */ + for (i = 0; i < iter->curr; i++) { + if (hist_entry__cmp(he_cache[i], &he_tmp) == 0) + return 0; + } he = __hists__add_entry(&evsel->hists, al, iter->parent, NULL, NULL, sample->period, sample->weight, @@ -519,6 +563,8 @@ iter_add_next_cumulative_entry(struct add_entry_iter *iter, if (he == NULL) return -ENOMEM; + he_cache[iter->curr++] = he; + /* * Only in the TUI browser we are doing integrated annotation, * so we don't allocated the extra space needed because the stdio @@ -547,6 +593,8 @@ iter_finish_cumulative_entry(struct add_entry_iter *iter, evsel->hists.stats.total_period += sample->period; hists__inc_nr_events(&evsel->hists, PERF_RECORD_SAMPLE); + free(iter->priv); + iter->priv = NULL; return 0; } -- 1.7.11.7
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