Commit bfb94675 authored Dec 05, 2024 by Ian Rogers Committed by Arnaldo Carvalho de Melo Dec 09, 2024

libperf cpumap: Grow array of read CPUs in smaller increments



Instead of growing the array by 2048, grow by the larger of the current
range or 16.

As ranges are typical for things like the online CPUs this will mean a
single allocation happens.

While uncore CPU maps will grow 16 at a time which is a value that is
generous except say on large servers.

Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ben Gainey <ben.gainey@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kyle Meyer <kyle.meyer@hpe.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241206044035.1062032-9-irogers@google.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent e9ca57d7

tools/lib/perf/cpumap.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -213,7 +213,7 @@ struct perf_cpu_map perf_cpu_map__new(const char cpu_list)
		goto invalid;

		if (nr_cpus == max_entries) {
		max_entries += MAX_NR_CPUS;
		max_entries += max(end_cpu - start_cpu + 1, 16UL);
		tmp = realloc(tmp_cpus, max_entries * sizeof(struct perf_cpu));
		if (tmp == NULL)
		goto invalid;
		@@ -227,14 +227,15 @@ struct perf_cpu_map perf_cpu_map__new(const char cpu_list)
		cpu_list = p;
		}

		if (nr_cpus > 0)
		if (nr_cpus > 0) {
		cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
		else if (*cpu_list != '\0') {
		} else if (*cpu_list != '\0') {
		pr_warning("Unexpected characters at end of cpu list ('%s'), using online CPUs.",
		cpu_list);
		cpus = perf_cpu_map__new_online_cpus();
		} else
		} else {
		cpus = perf_cpu_map__new_any_cpu();
		}
		invalid:
		free(tmp_cpus);
		out: