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2020-05-05perf tools: Simplify checking if SMT is active.Konstantin Khlebnikov1-0/+4
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 <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Dmitry Monakhov <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Kan Liang <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: http://lore.kernel.org/lkml/158817741394.748034.9273604089138009552.stgit@buzz Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
2020-05-05perf tools: Fix reading new topology attribute "core_cpus"Konstantin Khlebnikov1-3/+3
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: 0ccdb8407a46 ("perf tools: Apply new CPU topology sysfs attributes") Signed-off-by: Konstantin Khlebnikov <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Dmitry Monakhov <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Kan Liang <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: http://lore.kernel.org/lkml/158817718710.747528.11009278875028211991.stgit@buzz Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
2019-06-10perf tools: Apply new CPU topology sysfs attributesKan Liang1-2/+6
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 <[email protected]> Reviewed-by: Jiri Olsa <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
2017-08-22perf tools: Add utility function to detect SMT statusAndi Kleen1-0/+44
Add an smt_on() function to return if SMT is enabled or disabled. Used in the next patch. Signed-off-by: Andi Kleen <[email protected]> Acked-by: Jiri Olsa <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>