SMT now could be disabled via "/sys/devices/system/cpu/smt/control".
Status is shown in "/sys/devices/system/cpu/smt/active" simply as "0" / "1".
If this knob isn't here then fallback to checking topology as before.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/158817741394.748034.9273604089138009552.stgit@buzz
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Check if access("devices/system/cpu/cpu%d/topology/core_cpus", F_OK)
fails, which will happen unless the current directory is "/sys".
Simply try to read this file first.
Fixes: 0ccdb8407a ("perf tools: Apply new CPU topology sysfs attributes")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/158817718710.747528.11009278875028211991.stgit@buzz
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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>
Add an smt_on() function to return if SMT is enabled or disabled. Used
in the next patch.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20170811232634.30465-7-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
