Ian Rogers
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77d255d28b
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perf tools: Fix SMT detection fast read path
commit 4ffbe87e2d5b53bcb0213d8650bbe70bf942de6a upstream.
sysfs__read_int() returns 0 on success, and so the fast read path was
always failing.
Fixes: bb629484d9 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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2021-12-14 11:32:42 +01:00 |
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Konstantin Khlebnikov
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bb629484d9
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perf tools: Simplify checking if SMT is active.
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>
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2020-05-05 16:35:29 -03:00 |
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Konstantin Khlebnikov
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846de4371f
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perf tools: Fix reading new topology attribute "core_cpus"
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>
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2020-05-05 16:35:29 -03:00 |
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Kan Liang
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0ccdb8407a
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perf tools: Apply new CPU topology sysfs attributes
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>
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2019-06-10 16:20:11 -03:00 |
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Andi Kleen
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de5077c4e3
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perf tools: Add utility function to detect SMT status
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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2017-08-22 12:09:04 -03:00 |
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