diff options
| author | Ian Rogers <irogers@google.com> | 2026-10-25 23:50:44 -0700 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2026-10-27 16:59:18 -0300 |
| commit | 2fb45894e80d246ac6a9f0343343d581921cc3f2 (patch) | |
| tree | bc64d8d6d0ec1313e4e0fd2bf8a147552112fccb | |
| parent | 62d7cdc8d58702feb31b320f1713642e3977d7f3 (diff) | |
perf debug: Avoid calling eprintf() in pr_debugN() when verbose < n
pr_debugN() unconditionally evaluated its arguments and called eprintf()
-> veprintf() before checking if verbose >= n. In hot paths such as
dso__load_sym_internal(), two pr_debug4() calls per symbol accounted for
~15% of total CPU time in 'perf top' even at the default verbose == 0.
Guard eprintf() in pr_debugN() with unlikely(verbose >= (n)) and define
pr_debug() in terms of pr_debugN(1, ...).
In test__parsing_callback() (tools/perf/tests/pmu-events.c), move the
test_generic_metric(mexp, 0) call out of the pr_debug() argument list so
the metric evaluation continues to run during 'perf test' when verbose
== 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>
| -rw-r--r-- | tools/perf/tests/pmu-events.c | 5 | ||||
| -rw-r--r-- | tools/perf/util/debug.h | 5 |
2 files changed, 6 insertions, 4 deletions
diff --git a/tools/perf/tests/pmu-events.c b/tools/perf/tests/pmu-events.c index f507ce39439a..e6e4f4cf1fa2 100644 --- a/tools/perf/tests/pmu-events.c +++ b/tools/perf/tests/pmu-events.c @@ -906,9 +906,12 @@ static int test__parsing_callback(const struct pmu_metric *pm, struct metric_expr *mexp; list_for_each_entry (mexp, &me->head, nd) { + double result; + if (strcmp(mexp->metric_name, pm->metric_name)) continue; - pr_debug("Result %f\n", test_generic_metric(mexp, 0)); + result = test_generic_metric(mexp, 0); + pr_debug("Result %f\n", result); err = 0; (*failures)--; goto out_err; diff --git a/tools/perf/util/debug.h b/tools/perf/util/debug.h index 6b737e195ce1..7552c9171d90 100644 --- a/tools/perf/util/debug.h +++ b/tools/perf/util/debug.h @@ -33,10 +33,9 @@ extern int debug_type_profile; }) #define pr_info(fmt, ...) \ eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__) -#define pr_debug(fmt, ...) \ - eprintf(1, verbose, pr_fmt(fmt), ##__VA_ARGS__) #define pr_debugN(n, fmt, ...) \ - eprintf(n, verbose, pr_fmt(fmt), ##__VA_ARGS__) + (unlikely(verbose >= (n)) ? eprintf(n, verbose, pr_fmt(fmt), ##__VA_ARGS__) : 0) +#define pr_debug(fmt, ...) pr_debugN(1, pr_fmt(fmt), ##__VA_ARGS__) #define pr_debug2(fmt, ...) pr_debugN(2, pr_fmt(fmt), ##__VA_ARGS__) #define pr_debug3(fmt, ...) pr_debugN(3, pr_fmt(fmt), ##__VA_ARGS__) #define pr_debug4(fmt, ...) pr_debugN(4, pr_fmt(fmt), ##__VA_ARGS__) |