diff options
Diffstat (limited to 'tools/perf/util/smt.c')
-rw-r--r-- | tools/perf/util/smt.c | 65 |
1 files changed, 25 insertions, 40 deletions
diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c index 34f1b1b1176c..994e9e418227 100644 --- a/tools/perf/util/smt.c +++ b/tools/perf/util/smt.c @@ -1,52 +1,37 @@ -#include <stdio.h> -#include <stdlib.h> -#include <unistd.h> -#include <linux/bitops.h> +// SPDX-License-Identifier: GPL-2.0-only +#include <string.h> #include "api/fs/fs.h" +#include "cputopo.h" #include "smt.h" -int smt_on(void) +bool smt_on(const struct cpu_topology *topology) { static bool cached; - static int cached_result; - int cpu; - int ncpu; + static bool cached_result; + int fs_value; if (cached) return cached_result; - if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) >= 0) - goto done; + if (sysfs__read_int("devices/system/cpu/smt/active", &fs_value) >= 0) + cached_result = (fs_value == 1); + else + cached_result = cpu_topology__smt_on(topology); - ncpu = sysconf(_SC_NPROCESSORS_CONF); - for (cpu = 0; cpu < ncpu; cpu++) { - unsigned long long siblings; - char *str; - size_t strlen; - char fn[256]; - - snprintf(fn, sizeof fn, - "devices/system/cpu/cpu%d/topology/core_cpus", cpu); - if (sysfs__read_str(fn, &str, &strlen) < 0) { - snprintf(fn, sizeof fn, - "devices/system/cpu/cpu%d/topology/thread_siblings", - cpu); - if (sysfs__read_str(fn, &str, &strlen) < 0) - continue; - } - /* Entry is hex, but does not have 0x, so need custom parser */ - siblings = strtoull(str, NULL, 16); - free(str); - if (hweight64(siblings) > 1) { - cached_result = 1; - cached = true; - break; - } - } - if (!cached) { - cached_result = 0; -done: - cached = true; - } + cached = true; return cached_result; } + +bool core_wide(bool system_wide, const char *user_requested_cpu_list, + const struct cpu_topology *topology) +{ + /* If not everything running on a core is being recorded then we can't use core_wide. */ + if (!system_wide) + return false; + + /* Cheap case that SMT is disabled and therefore we're inherently core_wide. */ + if (!smt_on(topology)) + return true; + + return cpu_topology__core_wide(topology, user_requested_cpu_list); +} |