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From: Ian Rogers <irogers@google.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	 Arnaldo Carvalho de Melo <acme@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	 Mark Rutland <mark.rutland@arm.com>,
	 Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>,  Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	 Kan Liang <kan.liang@linux.intel.com>,
	James Clark <james.clark@linaro.org>,
	 Kyle Meyer <kyle.meyer@hpe.com>, Ben Gainey <ben.gainey@arm.com>,
	 linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v1 8/8] libperf cpumap: Grow array of read CPUs in smaller increments
Date: Thu,  5 Dec 2024 20:40:35 -0800	[thread overview]
Message-ID: <20241206044035.1062032-9-irogers@google.com> (raw)
In-Reply-To: <20241206044035.1062032-1-irogers@google.com>

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.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/lib/perf/cpumap.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
index 17413d3a2221..2237505f8f5f 100644
--- a/tools/lib/perf/cpumap.c
+++ b/tools/lib/perf/cpumap.c
@@ -212,7 +212,7 @@ 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;
@@ -226,14 +226,15 @@ 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:
-- 
2.47.0.338.g60cca15819-goog


  parent reply	other threads:[~2024-12-06  4:40 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-06  4:40 [PATCH v1 0/8] Cpumap improvements for large MAX_NR_CPUS Ian Rogers
2024-12-06  4:40 ` [PATCH v1 1/8] perf: Increase MAX_NR_CPUS to 4096 Ian Rogers
2024-12-06 10:24   ` Leo Yan
2024-12-06 16:25     ` Ian Rogers
2024-12-06 23:03       ` Leo Yan
2024-12-07  5:24         ` Ian Rogers
2024-12-09 21:35           ` David Laight
2024-12-09 21:47             ` Ian Rogers
2024-12-06  4:40 ` [PATCH v1 2/8] perf cpumap: Reduce transitive dependencies on libperf MAX_NR_CPUS Ian Rogers
2024-12-06  4:40 ` [PATCH v1 3/8] libperf cpumap: Hide/reduce scope of MAX_NR_CPUS Ian Rogers
2024-12-06  4:40 ` [PATCH v1 4/8] libperf cpumap: Be tolerant of newline at the end of a cpumask Ian Rogers
2024-12-06  4:40 ` [PATCH v1 5/8] perf pmu: Remove use of perf_cpu_map__read Ian Rogers
2024-12-06  4:40 ` [PATCH v1 6/8] libperf cpumap: " Ian Rogers
2024-12-06  4:40 ` [PATCH v1 7/8] libperf cpumap: Remove perf_cpu_map__read Ian Rogers
2024-12-06  4:40 ` Ian Rogers [this message]
2024-12-06 23:03 ` [PATCH v1 0/8] Cpumap improvements for large MAX_NR_CPUS Leo Yan
2024-12-09 16:04   ` Arnaldo Carvalho de Melo

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