Requiring the 'pmu->perf_event_attr_init_default' callback to be set to track user changes is a bit of a trap to fall in. It's hard to see that this is required when depending on the user change tracking.
It's possible to want all 0 defaults so not set it, but at the same time still do some programmatic setting of configs with evsel__set_config_if_unset(). Also if a PMU reverts to 0 defaults and deletes its existing callback, it will silently break existing uses of evsel__set_config_if_unset().
One way to fix this would be to assert in evsel__set_config_if_unset() if the changes weren't tracked, but that would be a possibly untested runtime failure. Instead, always track it as it's harmless and simplifies testing too.
Reviewed-by: Ian Rogers irogers@google.com Signed-off-by: James Clark james.clark@linaro.org --- tools/perf/util/parse-events.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 1f6e2213326d..c8f2962a06c7 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -1528,12 +1528,8 @@ static int parse_events_add_pmu(struct parse_events_state *parse_state, return -ENOMEM; }
- /* - * When using default config, record which bits of attr->config were - * changed by the user. - */ - if (pmu->perf_event_attr_init_default && - get_config_chgs(pmu, &parsed_terms, &config_terms)) { + /* Record which bits of attr->config were changed by the user. */ + if (get_config_chgs(pmu, &parsed_terms, &config_terms)) { parse_events_terms__exit(&parsed_terms); return -ENOMEM; }