diff options
| author | Ian Rogers <irogers@google.com> | 2025-02-10 22:12:31 +0300 |
|---|---|---|
| committer | Namhyung Kim <namhyung@kernel.org> | 2025-02-27 19:47:25 +0300 |
| commit | c760174401f605cf63314d3817069a40945f0e0b (patch) | |
| tree | 2654c020096f7ee1986c7dc7d5524ea0428faa58 /tools/lib/perf | |
| parent | 2337b7251dd5d3c58af877e6eee85a594c6b51f5 (diff) | |
| download | linux-c760174401f605cf63314d3817069a40945f0e0b.tar.xz | |
perf cpumap: Reduce cpu size from int to int16_t
Fewer than 32k logical CPUs are currently supported by perf. A cpumap
is indexed by an integer (see perf_cpu_map__cpu) yielding a perf_cpu
that wraps a 4-byte int for the logical CPU - the wrapping is done
deliberately to avoid confusing a logical CPU with an index into a
cpumap. Using a 4-byte int within the perf_cpu is larger than required
so this patch reduces it to the 2-byte int16_t. For a cpumap
containing 16 entries this will reduce the array size from 64 to 32
bytes. For very large servers with lots of logical CPUs the size
savings will be greater.
Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250210191231.156294-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Diffstat (limited to 'tools/lib/perf')
| -rw-r--r-- | tools/lib/perf/cpumap.c | 8 | ||||
| -rw-r--r-- | tools/lib/perf/include/perf/cpumap.h | 3 |
2 files changed, 6 insertions, 5 deletions
diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c index fcc47214062a..4454a5987570 100644 --- a/tools/lib/perf/cpumap.c +++ b/tools/lib/perf/cpumap.c @@ -185,7 +185,7 @@ struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list) while (isdigit(*cpu_list)) { p = NULL; start_cpu = strtoul(cpu_list, &p, 0); - if (start_cpu >= INT_MAX + if (start_cpu >= INT16_MAX || (*p != '\0' && *p != ',' && *p != '-' && *p != '\n')) goto invalid; @@ -194,7 +194,7 @@ struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list) p = NULL; end_cpu = strtoul(cpu_list, &p, 0); - if (end_cpu >= INT_MAX || (*p != '\0' && *p != ',' && *p != '\n')) + if (end_cpu >= INT16_MAX || (*p != '\0' && *p != ',' && *p != '\n')) goto invalid; if (end_cpu < start_cpu) @@ -209,7 +209,7 @@ struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list) for (; start_cpu <= end_cpu; start_cpu++) { /* check for duplicates */ for (i = 0; i < nr_cpus; i++) - if (tmp_cpus[i].cpu == (int)start_cpu) + if (tmp_cpus[i].cpu == (int16_t)start_cpu) goto invalid; if (nr_cpus == max_entries) { @@ -219,7 +219,7 @@ struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list) goto invalid; tmp_cpus = tmp; } - tmp_cpus[nr_cpus++].cpu = (int)start_cpu; + tmp_cpus[nr_cpus++].cpu = (int16_t)start_cpu; } if (*p) ++p; diff --git a/tools/lib/perf/include/perf/cpumap.h b/tools/lib/perf/include/perf/cpumap.h index 188a667babc6..8c1ab0f9194e 100644 --- a/tools/lib/perf/include/perf/cpumap.h +++ b/tools/lib/perf/include/perf/cpumap.h @@ -4,10 +4,11 @@ #include <perf/core.h> #include <stdbool.h> +#include <stdint.h> /** A wrapper around a CPU to avoid confusion with the perf_cpu_map's map's indices. */ struct perf_cpu { - int cpu; + int16_t cpu; }; struct perf_cache { |