[PATCH V2 5/8] perf top: check per event overwrite term

From: kan . liang
Date: Wed Dec 06 2017 - 18:34:14 EST


From: Kan Liang <kan.liang@xxxxxxxxx>

Per event overwrite term is not forbidden in perf top, which can bring
problems. Because perf top only support non-overwrite mode.

Check and forbid inconsistent per event overwrite term in the evlist.
Make it possible to support either non-overwrite or overwrite mode.
The overwrite mode is forbidden now, which will be removed when the
overwrite mode is supported later.

Signed-off-by: Kan Liang <kan.liang@xxxxxxxxx>
---
tools/perf/builtin-top.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 540461f..5e15d27 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -881,6 +881,56 @@ static void perf_top__mmap_read(struct perf_top *top)
perf_top__mmap_read_idx(top, i);
}

+/*
+ * Check per event overwrite term.
+ * perf top supports consistent mode for all events.
+ * Return -1 if the per event terms set but not consistent.
+ */
+static int perf_top_overwrite_check(struct perf_top *top)
+{
+ struct record_opts *opts = &top->record_opts;
+ struct perf_evlist *evlist = top->evlist;
+ struct perf_evsel_config_term *term;
+ struct list_head *config_terms;
+ struct perf_evsel *evsel;
+ int set, overwrite = -1;
+
+ evlist__for_each_entry(evlist, evsel) {
+ set = -1;
+ config_terms = &evsel->config_terms;
+ list_for_each_entry(term, config_terms, list) {
+ if (term->type == PERF_EVSEL__CONFIG_TERM_OVERWRITE)
+ set = term->val.overwrite ? 1 : 0;
+ }
+
+ /* no term for current and previous event (likely) */
+ if ((overwrite < 0) && (set < 0))
+ continue;
+
+ /* has term for both current and previous event, compare */
+ if ((overwrite >= 0) && (set >= 0) && (overwrite != set))
+ return -1;
+
+ /* no term for current event but has term for previous one */
+ if ((overwrite >= 0) && (set < 0))
+ return -1;
+
+ /* has term for current event */
+ if ((overwrite < 0) && (set >= 0)) {
+ /* if it's first event, set overwrite */
+ if (evsel == perf_evlist__first(evlist))
+ overwrite = set;
+ else
+ return -1;
+ }
+ }
+
+ if ((overwrite >= 0) && (opts->overwrite != overwrite))
+ opts->overwrite = overwrite;
+
+ return 0;
+}
+
static int perf_top__start_counters(struct perf_top *top)
{
char msg[BUFSIZ];
@@ -890,6 +940,16 @@ static int perf_top__start_counters(struct perf_top *top)

perf_evlist__config(evlist, opts, &callchain_param);

+ if (perf_top_overwrite_check(top)) {
+ ui__error("perf top support consistent mode for all events\n");
+ goto out_err;
+ }
+
+ if (opts->overwrite) {
+ ui__error("not support overwrite mode yet\n");
+ goto out_err;
+ }
+
evlist__for_each_entry(evlist, counter) {
try_again:
if (perf_evsel__open(counter, top->evlist->cpus,
--
2.5.5