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2022-01-12perf tools: Probe non-deprecated sysfs path 1stIan Rogers1-3/+2
Following Documentation/ABI/stable/sysfs-devices-system-cpu the /sys/devices/system/cpu/cpuX/topology/core_cpus is deprecated in favor of thread_siblings, so probe thread_siblings before falling back on core_cpus. Signed-off-by: Ian Rogers <irogers@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: John Garry <john.garry@huawei.com> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Clarke <pc@us.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: https://lore.kernel.org/r/20211124001231.3277836-4-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-01-12perf tools: Fix SMT fallback with large core countsIan Rogers1-10/+58
strtoull can only read a 64-bit bitmap. On an AMD EPYC core_cpus may look like: 00000000,00000000,00000000,00000001,00000000,00000000,00000000,00000001 and so the sibling wasn't spotted. Fix by writing a simple hweight string parser. Signed-off-by: Ian Rogers <irogers@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: John Garry <john.garry@huawei.com> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Clarke <pc@us.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: https://lore.kernel.org/r/20211124001231.3277836-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-12-06perf tools: Fix SMT detection fast read pathIan Rogers1-1/+1
sysfs__read_int() returns 0 on success, and so the fast read path was always failing. Fixes: bb629484d924118e ("perf tools: Simplify checking if SMT is active.") Signed-off-by: Ian Rogers <irogers@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: John Garry <john.garry@huawei.com> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Clarke <pc@us.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20211124001231.3277836-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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 <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>
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 <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>
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 <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>
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 <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>
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