<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/tools/perf/util/sort.c, branch linux-6.4.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>perf evsel: Introduce evsel__name_is() method to check if the evsel name is equal to a given string</title>
<updated>2023-04-24T17:28:11+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2023-04-20T18:54:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ce1d3bc2733224573600e5564203345caea814eb'/>
<id>ce1d3bc2733224573600e5564203345caea814eb</id>
<content type='text'>
This makes the logic a bit clear by avoiding the !strcmp() pattern and
also a way to intercept the pointer if we need to do extra validation on
it or to do lazy setting of evsel-&gt;name via evsel__name(evsel).

Reviewed-by: "Liang, Kan" &lt;kan.liang@linux.intel.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/lkml/ZEGLM8VehJbS0gP2@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This makes the logic a bit clear by avoiding the !strcmp() pattern and
also a way to intercept the pointer if we need to do extra validation on
it or to do lazy setting of evsel-&gt;name via evsel__name(evsel).

Reviewed-by: "Liang, Kan" &lt;kan.liang@linux.intel.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/lkml/ZEGLM8VehJbS0gP2@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf dso: Fix use before NULL check introduced by map__dso() introduction</title>
<updated>2023-04-19T13:51:48+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2023-04-18T15:46:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3ad1be6faef9a482c3098928220fcafaa51a1283'/>
<id>3ad1be6faef9a482c3098928220fcafaa51a1283</id>
<content type='text'>
James Clark noticed that the recent 63df0e4bc368adbd ("perf map: Add
accessor for dso") patch accessed map-&gt;dso before the 'map' variable was
NULL checked, which is a change in logic that leads to segmentation
faults, so comb thru that patch to fix similar cases.

Fixes: 63df0e4bc368adbd ("perf map: Add accessor for dso")
Acked-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org
Cc: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/lkml/ZD68RYCVT8hqPuxr@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
James Clark noticed that the recent 63df0e4bc368adbd ("perf map: Add
accessor for dso") patch accessed map-&gt;dso before the 'map' variable was
NULL checked, which is a change in logic that leads to segmentation
faults, so comb thru that patch to fix similar cases.

Fixes: 63df0e4bc368adbd ("perf map: Add accessor for dso")
Acked-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org
Cc: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/lkml/ZD68RYCVT8hqPuxr@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf map: Delete two variable initialisations before null pointer checks in sort__sym_from_cmp()</title>
<updated>2023-04-13T22:01:51+00:00</updated>
<author>
<name>Markus Elfring</name>
<email>Markus.Elfring@web.de</email>
</author>
<published>2023-04-13T12:46:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c160118a90d4acf335993d8d59b02ae2147a524e'/>
<id>c160118a90d4acf335993d8d59b02ae2147a524e</id>
<content type='text'>
Addresses of two data structure members were determined before
corresponding null pointer checks in the implementation of the function
“sort__sym_from_cmp”.

Thus avoid the risk for undefined behaviour by removing extra
initialisations for the local variables “from_l” and “from_r” (also
because they were already reassigned with the same value behind this
pointer check).

This issue was detected by using the Coccinelle software.

Fixes: 1b9e97a2a95e4941 ("perf tools: Fix report -F symbol_from for data without branch info")
Signed-off-by: &lt;elfring@users.sourceforge.net&gt;
Acked-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/cocci/54a21fea-64e3-de67-82ef-d61b90ffad05@web.de/
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Addresses of two data structure members were determined before
corresponding null pointer checks in the implementation of the function
“sort__sym_from_cmp”.

Thus avoid the risk for undefined behaviour by removing extra
initialisations for the local variables “from_l” and “from_r” (also
because they were already reassigned with the same value behind this
pointer check).

This issue was detected by using the Coccinelle software.

Fixes: 1b9e97a2a95e4941 ("perf tools: Fix report -F symbol_from for data without branch info")
Signed-off-by: &lt;elfring@users.sourceforge.net&gt;
Acked-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/cocci/54a21fea-64e3-de67-82ef-d61b90ffad05@web.de/
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf map: Add accessors for -&gt;prot, -&gt;priv and -&gt;flags</title>
<updated>2023-04-07T01:10:59+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-04-04T20:59:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ddee3f2bddc11f850f7f6fcfc04bc26ceeab23ce'/>
<id>ddee3f2bddc11f850f7f6fcfc04bc26ceeab23ce</id>
<content type='text'>
Later changes will add reference count checking for 'struct map'. Add an
accessor so that the reference count check is only necessary in one
place.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexey Bayduraev &lt;alexey.v.bayduraev@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Darren Hart &lt;dvhart@infradead.org&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: Dmitriy Vyukov &lt;dvyukov@google.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Hao Luo &lt;haoluo@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Shunsuke Nakamura &lt;nakamura.shun@fujitsu.com&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Stephen Brennan &lt;stephen.s.brennan@oracle.com&gt;
Cc: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Yury Norov &lt;yury.norov@gmail.com&gt;
Link: https://lore.kernel.org/r/20230404205954.2245628-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Later changes will add reference count checking for 'struct map'. Add an
accessor so that the reference count check is only necessary in one
place.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexey Bayduraev &lt;alexey.v.bayduraev@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Darren Hart &lt;dvhart@infradead.org&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: Dmitriy Vyukov &lt;dvyukov@google.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Hao Luo &lt;haoluo@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Shunsuke Nakamura &lt;nakamura.shun@fujitsu.com&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Stephen Brennan &lt;stephen.s.brennan@oracle.com&gt;
Cc: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Yury Norov &lt;yury.norov@gmail.com&gt;
Link: https://lore.kernel.org/r/20230404205954.2245628-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf map: Add helper for -&gt;map_ip() and -&gt;unmap_ip()</title>
<updated>2023-04-07T01:10:17+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-04-04T20:59:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=78a1f7cd9000d5d633268a2acb2d9b62d41a2f2c'/>
<id>78a1f7cd9000d5d633268a2acb2d9b62d41a2f2c</id>
<content type='text'>
Later changes will add reference count checking for struct map, add a
helper function to invoke the map_ip and unmap_ip function pointers. The
helper allows the reference count check to be in fewer places.

Committer notes:

Add missing conversions to:

  tools/perf/util/map.c
  tools/perf/util/cs-etm.c
  tools/perf/util/annotate.c
  tools/perf/arch/powerpc/util/sym-handling.c
  tools/perf/arch/s390/annotate/instructions.c

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexey Bayduraev &lt;alexey.v.bayduraev@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Darren Hart &lt;dvhart@infradead.org&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: Dmitriy Vyukov &lt;dvyukov@google.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Hao Luo &lt;haoluo@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Shunsuke Nakamura &lt;nakamura.shun@fujitsu.com&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Stephen Brennan &lt;stephen.s.brennan@oracle.com&gt;
Cc: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Yury Norov &lt;yury.norov@gmail.com&gt;
Link: https://lore.kernel.org/r/20230404205954.2245628-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Later changes will add reference count checking for struct map, add a
helper function to invoke the map_ip and unmap_ip function pointers. The
helper allows the reference count check to be in fewer places.

Committer notes:

Add missing conversions to:

  tools/perf/util/map.c
  tools/perf/util/cs-etm.c
  tools/perf/util/annotate.c
  tools/perf/arch/powerpc/util/sym-handling.c
  tools/perf/arch/s390/annotate/instructions.c

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexey Bayduraev &lt;alexey.v.bayduraev@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Darren Hart &lt;dvhart@infradead.org&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: Dmitriy Vyukov &lt;dvyukov@google.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Hao Luo &lt;haoluo@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Shunsuke Nakamura &lt;nakamura.shun@fujitsu.com&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Stephen Brennan &lt;stephen.s.brennan@oracle.com&gt;
Cc: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Yury Norov &lt;yury.norov@gmail.com&gt;
Link: https://lore.kernel.org/r/20230404205954.2245628-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf map: Add accessor for dso</title>
<updated>2023-04-04T19:41:57+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-03-20T21:22:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=63df0e4bc368adbd12ed70ed4789d8d52d65661d'/>
<id>63df0e4bc368adbd12ed70ed4789d8d52d65661d</id>
<content type='text'>
Later changes will add reference count checking for struct map, with
dso being the most frequently accessed variable. Add an accessor so
that the reference count check is only necessary in one place.

Additional changes:
 - add a dso variable to avoid repeated map__dso calls.
 - in builtin-mem.c dump_raw_samples, code only partially tested for
   dso == NULL. Make the possibility of NULL consistent.
 - in thread.c thread__memcpy fix use of spaces and use tabs.

Committer notes:

Did missing conversions on these files:

   tools/perf/arch/powerpc/util/skip-callchain-idx.c
   tools/perf/arch/powerpc/util/sym-handling.c
   tools/perf/ui/browsers/hists.c
   tools/perf/ui/gtk/annotate.c
   tools/perf/util/cs-etm.c
   tools/perf/util/thread.c
   tools/perf/util/unwind-libunwind-local.c
   tools/perf/util/unwind-libunwind.c

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexey Bayduraev &lt;alexey.v.bayduraev@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Darren Hart &lt;dvhart@infradead.org&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: Dmitriy Vyukov &lt;dvyukov@google.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Hao Luo &lt;haoluo@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Shunsuke Nakamura &lt;nakamura.shun@fujitsu.com&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Stephen Brennan &lt;stephen.s.brennan@oracle.com&gt;
Cc: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Yury Norov &lt;yury.norov@gmail.com&gt;
Link: https://lore.kernel.org/r/20230320212248.1175731-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Later changes will add reference count checking for struct map, with
dso being the most frequently accessed variable. Add an accessor so
that the reference count check is only necessary in one place.

Additional changes:
 - add a dso variable to avoid repeated map__dso calls.
 - in builtin-mem.c dump_raw_samples, code only partially tested for
   dso == NULL. Make the possibility of NULL consistent.
 - in thread.c thread__memcpy fix use of spaces and use tabs.

Committer notes:

Did missing conversions on these files:

   tools/perf/arch/powerpc/util/skip-callchain-idx.c
   tools/perf/arch/powerpc/util/sym-handling.c
   tools/perf/ui/browsers/hists.c
   tools/perf/ui/gtk/annotate.c
   tools/perf/util/cs-etm.c
   tools/perf/util/thread.c
   tools/perf/util/unwind-libunwind-local.c
   tools/perf/util/unwind-libunwind.c

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexey Bayduraev &lt;alexey.v.bayduraev@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Darren Hart &lt;dvhart@infradead.org&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: Dmitriy Vyukov &lt;dvyukov@google.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Hao Luo &lt;haoluo@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Shunsuke Nakamura &lt;nakamura.shun@fujitsu.com&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Stephen Brennan &lt;stephen.s.brennan@oracle.com&gt;
Cc: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Yury Norov &lt;yury.norov@gmail.com&gt;
Link: https://lore.kernel.org/r/20230320212248.1175731-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf maps: Add functions to access maps</title>
<updated>2023-04-04T18:45:38+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-03-20T21:22:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5ab6d715c32f6249415bcd1972bae7e6c03636f0'/>
<id>5ab6d715c32f6249415bcd1972bae7e6c03636f0</id>
<content type='text'>
Introduce functions to access struct maps. These functions reduce the
number of places reference counting is necessary. While tidying APIs do
some small const-ification, in particlar to unwind_libunwind_ops.

Committer notes:

Fixed up tools/perf/util/unwind-libunwind.c:

-               return ops-&gt;get_entries(cb, arg, thread, data, max_stack);
+               return ops-&gt;get_entries(cb, arg, thread, data, max_stack, best_effort);

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexey Bayduraev &lt;alexey.v.bayduraev@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Darren Hart &lt;dvhart@infradead.org&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: Dmitriy Vyukov &lt;dvyukov@google.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Hao Luo &lt;haoluo@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Shunsuke Nakamura &lt;nakamura.shun@fujitsu.com&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Stephen Brennan &lt;stephen.s.brennan@oracle.com&gt;
Cc: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Yury Norov &lt;yury.norov@gmail.com&gt;
Link: https://lore.kernel.org/r/20230320212248.1175731-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Introduce functions to access struct maps. These functions reduce the
number of places reference counting is necessary. While tidying APIs do
some small const-ification, in particlar to unwind_libunwind_ops.

Committer notes:

Fixed up tools/perf/util/unwind-libunwind.c:

-               return ops-&gt;get_entries(cb, arg, thread, data, max_stack);
+               return ops-&gt;get_entries(cb, arg, thread, data, max_stack, best_effort);

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexey Bayduraev &lt;alexey.v.bayduraev@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Darren Hart &lt;dvhart@infradead.org&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: Dmitriy Vyukov &lt;dvyukov@google.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Hao Luo &lt;haoluo@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Riccardo Mancini &lt;rickyman7@gmail.com&gt;
Cc: Shunsuke Nakamura &lt;nakamura.shun@fujitsu.com&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Stephen Brennan &lt;stephen.s.brennan@oracle.com&gt;
Cc: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Yury Norov &lt;yury.norov@gmail.com&gt;
Link: https://lore.kernel.org/r/20230320212248.1175731-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf hist: Improve srcfile sort key performance (really)</title>
<updated>2023-04-04T12:39:55+00:00</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2023-03-23T02:50:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6094c7744bb0563e833e81d8df8513f9a4e7a257'/>
<id>6094c7744bb0563e833e81d8df8513f9a4e7a257</id>
<content type='text'>
The earlier commit f0cdde28fecc0d7f ("perf hist: Improve srcfile sort
key performance") updated the srcfile logic but missed to change the
-&gt;cmp() callback which is called for every sample.

It should use the same logic like in the srcline to speed up the
processing because it'd return the same information repeatedly for the
same address.  The real processing will be done in
sort__srcfile_collapse().

Fixes: f0cdde28fecc0d7f ("perf hist: Improve srcfile sort key performance")
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20230323025005.191239-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The earlier commit f0cdde28fecc0d7f ("perf hist: Improve srcfile sort
key performance") updated the srcfile logic but missed to change the
-&gt;cmp() callback which is called for every sample.

It should use the same logic like in the srcline to speed up the
processing because it'd return the same information repeatedly for the
same address.  The real processing will be done in
sort__srcfile_collapse().

Fixes: f0cdde28fecc0d7f ("perf hist: Improve srcfile sort key performance")
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20230323025005.191239-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf report: Add 'simd' sort field</title>
<updated>2023-03-20T22:28:21+00:00</updated>
<author>
<name>German Gomez</name>
<email>german.gomez@arm.com</email>
</author>
<published>2023-03-20T15:15:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ea15483e7c55f73809cd9e208fff511966539ee5'/>
<id>ea15483e7c55f73809cd9e208fff511966539ee5</id>
<content type='text'>
Add 'simd' sort field to visualize SIMD ops in 'perf report'.

Rows are labeled with the SIMD ISA, and the type of predicate (if any):

  - [p] partial predicate
  - [e] empty predicate (no elements in the vector being used)

Example with Arm SPE and SVE (Scalable Vector Extension):

  #include &lt;arm_sve.h&gt;

  double src[1025], dst[1025];

  int main(void) {
    svfloat64_t vc = svdup_f64(1);
    for(;;)
      for(int i = 0; i &lt; 1025; i += svcntd())
      {
        svbool_t pg = svwhilelt_b64(i, 1025);
        svfloat64_t vsrc = svld1(pg, &amp;src[i]);
        svfloat64_t vdst = svadd_x(pg, vsrc, vc);
        svst1(pg, &amp;dst[i], vdst);
      }
    return 0;
  }

  ... compiled using "gcc-11 -march=armv8-a+sve -O3"

Profiling on a platform that implements FEAT_SVE and FEAT_SPEv1p1:

  $ perf record -e arm_spe_0// -- ./a.out
  $ perf report --itrace=i1i -s overhead,pid,simd,sym

  Overhead      Pid:Command   Simd     Symbol
  ........  ................  .......  ......................

    53.76%    10758:program            [.] main
    46.14%    10758:program   [.] SVE  [.] main
     0.09%    10758:program   [p] SVE  [.] main

The report shows 0.09% of the sampled SVE operations use partial
predicates due to src and dst arrays not being multiples of the vector
register lengths.

Signed-off-by: German Gomez &lt;german.gomez@arm.com&gt;
Acked-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Anshuman.Khandual@arm.com
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230320151509.1137462-2-james.clark@arm.com
Signed-off-by: James Clark &lt;james.clark@arm.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add 'simd' sort field to visualize SIMD ops in 'perf report'.

Rows are labeled with the SIMD ISA, and the type of predicate (if any):

  - [p] partial predicate
  - [e] empty predicate (no elements in the vector being used)

Example with Arm SPE and SVE (Scalable Vector Extension):

  #include &lt;arm_sve.h&gt;

  double src[1025], dst[1025];

  int main(void) {
    svfloat64_t vc = svdup_f64(1);
    for(;;)
      for(int i = 0; i &lt; 1025; i += svcntd())
      {
        svbool_t pg = svwhilelt_b64(i, 1025);
        svfloat64_t vsrc = svld1(pg, &amp;src[i]);
        svfloat64_t vdst = svadd_x(pg, vsrc, vc);
        svst1(pg, &amp;dst[i], vdst);
      }
    return 0;
  }

  ... compiled using "gcc-11 -march=armv8-a+sve -O3"

Profiling on a platform that implements FEAT_SVE and FEAT_SPEv1p1:

  $ perf record -e arm_spe_0// -- ./a.out
  $ perf report --itrace=i1i -s overhead,pid,simd,sym

  Overhead      Pid:Command   Simd     Symbol
  ........  ................  .......  ......................

    53.76%    10758:program            [.] main
    46.14%    10758:program   [.] SVE  [.] main
     0.09%    10758:program   [p] SVE  [.] main

The report shows 0.09% of the sampled SVE operations use partial
predicates due to src and dst arrays not being multiples of the vector
register lengths.

Signed-off-by: German Gomez &lt;german.gomez@arm.com&gt;
Acked-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Anshuman.Khandual@arm.com
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230320151509.1137462-2-james.clark@arm.com
Signed-off-by: James Clark &lt;james.clark@arm.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf c2c: Add report option to show false sharing in adjacent cachelines</title>
<updated>2023-02-16T12:33:45+00:00</updated>
<author>
<name>Feng Tang</name>
<email>feng.tang@intel.com</email>
</author>
<published>2023-02-14T07:58:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1470a108a60e8c0c4d19da10117c9b98f0078654'/>
<id>1470a108a60e8c0c4d19da10117c9b98f0078654</id>
<content type='text'>
Many platforms have feature of adjacent cachelines prefetch, when it is
enabled, for data in RAM of 2 cachelines (2N and 2N+1) granularity, if
one is fetched to cache, the other one could likely be fetched too,
which sort of extends the cacheline size to double, thus the false
sharing could happens in adjacent cachelines.

0Day has captured performance changed related with this [1], and some
commercial software explicitly makes its hot global variables 128 bytes
aligned (2 cache lines) to avoid this kind of extended false sharing.

So add an option "--double-cl" for 'perf c2c report' to show false
sharing in double cache line granularity, which acts just like the
cacheline size is doubled. There is no change to c2c record. The
hardware events of shared cacheline are still per cacheline, and this
option just changes the granularity of how events are grouped and
displayed.

In the 'perf c2c report' output below (will-it-scale's 'pagefault2' case
on old kernel):

  ----------------------------------------------------------------------
     26       31        2        0        0        0  0xffff888103ec6000
  ----------------------------------------------------------------------
   35.48%   50.00%    0.00%    0.00%    0.00%   0x10     0       1  0xffffffff8133148b   1153   66    971   3748   74  [k] get_mem_cgroup_from_mm
    6.45%    0.00%    0.00%    0.00%    0.00%   0x10     0       1  0xffffffff813396e4    570    0   1531    879   75  [k] mem_cgroup_charge
   25.81%   50.00%    0.00%    0.00%    0.00%   0x54     0       1  0xffffffff81331472    949   70    593   3359   74  [k] get_mem_cgroup_from_mm
   19.35%    0.00%    0.00%    0.00%    0.00%   0x54     0       1  0xffffffff81339686   1352    0   1073   1022   74  [k] mem_cgroup_charge
    9.68%    0.00%    0.00%    0.00%    0.00%   0x54     0       1  0xffffffff813396d6   1401    0    863    768   74  [k] mem_cgroup_charge
    3.23%    0.00%    0.00%    0.00%    0.00%   0x54     0       1  0xffffffff81333106    618    0    804     11    9  [k] uncharge_batch

The offset 0x10 and 0x54 used to displayed in 2 groups, and now they are
listed together to give users a hint of extended false sharing.

[1]. https://lore.kernel.org/lkml/20201102091543.GM31092@shao2-debian/

Committer notes:

Link: https://lore.kernel.org/r/Y+wvVNWqXb70l4uy@feng-clx

Removed -a, leaving just as --double-cl, as this probably is not used so
frequently and perhaps will be even auto-detected if we manage to record
the MSR where this is configured.

Reviewed-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Reviewed-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Signed-off-by: Feng Tang &lt;feng.tang@intel.com&gt;
Tested-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Acked-by: Joe Mario &lt;jmario@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Tim Chen &lt;tim.c.chen@intel.com&gt;
Cc: Xing Zhengjun &lt;zhengjun.xing@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20230214075823.246414-1-feng.tang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Many platforms have feature of adjacent cachelines prefetch, when it is
enabled, for data in RAM of 2 cachelines (2N and 2N+1) granularity, if
one is fetched to cache, the other one could likely be fetched too,
which sort of extends the cacheline size to double, thus the false
sharing could happens in adjacent cachelines.

0Day has captured performance changed related with this [1], and some
commercial software explicitly makes its hot global variables 128 bytes
aligned (2 cache lines) to avoid this kind of extended false sharing.

So add an option "--double-cl" for 'perf c2c report' to show false
sharing in double cache line granularity, which acts just like the
cacheline size is doubled. There is no change to c2c record. The
hardware events of shared cacheline are still per cacheline, and this
option just changes the granularity of how events are grouped and
displayed.

In the 'perf c2c report' output below (will-it-scale's 'pagefault2' case
on old kernel):

  ----------------------------------------------------------------------
     26       31        2        0        0        0  0xffff888103ec6000
  ----------------------------------------------------------------------
   35.48%   50.00%    0.00%    0.00%    0.00%   0x10     0       1  0xffffffff8133148b   1153   66    971   3748   74  [k] get_mem_cgroup_from_mm
    6.45%    0.00%    0.00%    0.00%    0.00%   0x10     0       1  0xffffffff813396e4    570    0   1531    879   75  [k] mem_cgroup_charge
   25.81%   50.00%    0.00%    0.00%    0.00%   0x54     0       1  0xffffffff81331472    949   70    593   3359   74  [k] get_mem_cgroup_from_mm
   19.35%    0.00%    0.00%    0.00%    0.00%   0x54     0       1  0xffffffff81339686   1352    0   1073   1022   74  [k] mem_cgroup_charge
    9.68%    0.00%    0.00%    0.00%    0.00%   0x54     0       1  0xffffffff813396d6   1401    0    863    768   74  [k] mem_cgroup_charge
    3.23%    0.00%    0.00%    0.00%    0.00%   0x54     0       1  0xffffffff81333106    618    0    804     11    9  [k] uncharge_batch

The offset 0x10 and 0x54 used to displayed in 2 groups, and now they are
listed together to give users a hint of extended false sharing.

[1]. https://lore.kernel.org/lkml/20201102091543.GM31092@shao2-debian/

Committer notes:

Link: https://lore.kernel.org/r/Y+wvVNWqXb70l4uy@feng-clx

Removed -a, leaving just as --double-cl, as this probably is not used so
frequently and perhaps will be even auto-detected if we manage to record
the MSR where this is configured.

Reviewed-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Reviewed-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Signed-off-by: Feng Tang &lt;feng.tang@intel.com&gt;
Tested-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Acked-by: Joe Mario &lt;jmario@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Tim Chen &lt;tim.c.chen@intel.com&gt;
Cc: Xing Zhengjun &lt;zhengjun.xing@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20230214075823.246414-1-feng.tang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
