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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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0ccdb8407a
The existing "thread_siblings" and "thread_siblings_list" attribute will be deprecated. Use the new CPU topology sysfs attributes, "core_cpus" and "core_cpus_list", which are synonymous with the deprecated attributes. Check the new name first. If not available, use the deprecated name to be compatible with old kernel. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1559688644-106558-5-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
48 lines
966 B
C
48 lines
966 B
C
#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <linux/bitops.h>
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#include "api/fs/fs.h"
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#include "smt.h"
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int smt_on(void)
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{
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static bool cached;
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static int cached_result;
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int cpu;
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int ncpu;
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if (cached)
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return cached_result;
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ncpu = sysconf(_SC_NPROCESSORS_CONF);
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for (cpu = 0; cpu < ncpu; cpu++) {
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unsigned long long siblings;
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char *str;
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size_t strlen;
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char fn[256];
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snprintf(fn, sizeof fn,
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"devices/system/cpu/cpu%d/topology/core_cpus", cpu);
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if (access(fn, F_OK) == -1) {
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snprintf(fn, sizeof fn,
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"devices/system/cpu/cpu%d/topology/thread_siblings",
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cpu);
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}
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if (sysfs__read_str(fn, &str, &strlen) < 0)
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continue;
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/* Entry is hex, but does not have 0x, so need custom parser */
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siblings = strtoull(str, NULL, 16);
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free(str);
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if (hweight64(siblings) > 1) {
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cached_result = 1;
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cached = true;
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break;
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}
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}
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if (!cached) {
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cached_result = 0;
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cached = true;
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}
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return cached_result;
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}
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