diff options
Diffstat (limited to 'tools/perf/util/smt.c')
-rw-r--r-- | tools/perf/util/smt.c | 95 |
1 files changed, 9 insertions, 86 deletions
diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c index 8fed03283c85..ce90c4ee4138 100644 --- a/tools/perf/util/smt.c +++ b/tools/perf/util/smt.c @@ -1,100 +1,23 @@ // SPDX-License-Identifier: GPL-2.0-only -#include <stdio.h> -#include <stdlib.h> -#include <unistd.h> -#include <linux/bitops.h> +#include <string.h> #include "api/fs/fs.h" +#include "cputopo.h" #include "smt.h" -/** - * hweight_str - Returns the number of bits set in str. Stops at first non-hex - * or ',' character. - */ -static int hweight_str(char *str) -{ - int result = 0; - - while (*str) { - switch (*str++) { - case '0': - case ',': - break; - case '1': - case '2': - case '4': - case '8': - result++; - break; - case '3': - case '5': - case '6': - case '9': - case 'a': - case 'A': - case 'c': - case 'C': - result += 2; - break; - case '7': - case 'b': - case 'B': - case 'd': - case 'D': - case 'e': - case 'E': - result += 3; - break; - case 'f': - case 'F': - result += 4; - break; - default: - goto done; - } - } -done: - return result; -} - -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) { - cached = true; - return cached_result; - } - - cached_result = 0; - ncpu = sysconf(_SC_NPROCESSORS_CONF); - for (cpu = 0; cpu < ncpu; cpu++) { - unsigned long long siblings; - char *str; - size_t strlen; - char fn[256]; + 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); - snprintf(fn, sizeof fn, - "devices/system/cpu/cpu%d/topology/thread_siblings", cpu); - if (sysfs__read_str(fn, &str, &strlen) < 0) { - snprintf(fn, sizeof fn, - "devices/system/cpu/cpu%d/topology/core_cpus", cpu); - if (sysfs__read_str(fn, &str, &strlen) < 0) - continue; - } - /* Entry is hex, but does not have 0x, so need custom parser */ - siblings = hweight_str(str); - free(str); - if (siblings > 1) { - cached_result = 1; - break; - } - } cached = true; return cached_result; } |