Messages in this thread Patch in this message | | | Subject | [PATCH v2 1/3] perf tool: fix reading new topology attribute "core_cpus" | From | Konstantin Khlebnikov <> | Date | Wed, 29 Apr 2020 19:19:47 +0300 |
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Check access("devices/system/cpu/cpu%d/topology/core_cpus", F_OK) fails, unless current directory is "/sys". Simply try read this file first.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Fixes: 0ccdb8407a46 ("perf tools: Apply new CPU topology sysfs attributes") --- tools/perf/util/smt.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c index 3b791ef2cd50..8481842e9edb 100644 --- a/tools/perf/util/smt.c +++ b/tools/perf/util/smt.c @@ -24,13 +24,13 @@ int smt_on(void) snprintf(fn, sizeof fn, "devices/system/cpu/cpu%d/topology/core_cpus", cpu); - if (access(fn, F_OK) == -1) { + 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; } - 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);
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