<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/tools/perf/Documentation, branch v4.20-rc6</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>perf record: Support weak groups</title>
<updated>2018-11-05T17:37:10+00:00</updated>
<author>
<name>Andi Kleen</name>
<email>ak@linux.intel.com</email>
</author>
<published>2018-10-01T19:59:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=cf99ad1424c54fc84b84d3a3deb57a48c340c30a'/>
<id>cf99ad1424c54fc84b84d3a3deb57a48c340c30a</id>
<content type='text'>
Implement a weak group fallback for 'perf record', similar to the
existing 'perf stat' support.  This allows to use groups that might be
longer than the available counters without failing.

Before:

  $ perf record  -e '{cycles,cache-misses,cache-references,cpu_clk_unhalted.thread,cycles,cycles,cycles}' -a sleep 1
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles).
  /bin/dmesg | grep -i perf may provide additional information.

After:

  $ ./perf record  -e '{cycles,cache-misses,cache-references,cpu_clk_unhalted.thread,cycles,cycles,cycles}:W' -a sleep 1
  WARNING: No sample_id_all support, falling back to unordered processing
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 8.136 MB perf.data (134069 samples) ]

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: http://lkml.kernel.org/r/20181001195927.14211-2-andi@firstfloor.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>
Implement a weak group fallback for 'perf record', similar to the
existing 'perf stat' support.  This allows to use groups that might be
longer than the available counters without failing.

Before:

  $ perf record  -e '{cycles,cache-misses,cache-references,cpu_clk_unhalted.thread,cycles,cycles,cycles}' -a sleep 1
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles).
  /bin/dmesg | grep -i perf may provide additional information.

After:

  $ ./perf record  -e '{cycles,cache-misses,cache-references,cpu_clk_unhalted.thread,cycles,cycles,cycles}:W' -a sleep 1
  WARNING: No sample_id_all support, falling back to unordered processing
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 8.136 MB perf.data (134069 samples) ]

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: http://lkml.kernel.org/r/20181001195927.14211-2-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf top: Do not use overwrite mode by default</title>
<updated>2018-10-31T12:57:31+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2018-10-29T12:47:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=218d61110f69632974034b6e27686ce482a1c455'/>
<id>218d61110f69632974034b6e27686ce482a1c455</id>
<content type='text'>
Enabling --overwrite mode allows us to to use just the most recent
records, which helps in high core count machines such as Knights
Landing/Mill, but right now is being disabled by default as the pausing
used in this technique is leading to loss of metadata events such as
PERF_RECORD_MMAP which makes 'perf top' unable to resolve samples,
leading to lots of unknown samples appearing on the UI.

Enabling this may be useful if you are in such machines and profiling a
workload that doesn't creates short lived threads and/or doesn't uses
many executable mmap operations.

Work is being planed to solve this situation, till then, this will
remain disabled by default.

Reported-by: David Miller &lt;davem@davemloft.net&gt;
Acked-by: Kan Liang &lt;kan.liang@intel.com&gt;
Link: https://lkml.kernel.org/r/4f84468f-37d9-cf1b-12c1-514ef74b6a48@linux.intel.com
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Fixes: ebebbf082357 ("perf top: Switch default mode to overwrite mode")
Link: https://lkml.kernel.org/n/tip-ehvf77vi1si9409r7p4wx788@git.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>
Enabling --overwrite mode allows us to to use just the most recent
records, which helps in high core count machines such as Knights
Landing/Mill, but right now is being disabled by default as the pausing
used in this technique is leading to loss of metadata events such as
PERF_RECORD_MMAP which makes 'perf top' unable to resolve samples,
leading to lots of unknown samples appearing on the UI.

Enabling this may be useful if you are in such machines and profiling a
workload that doesn't creates short lived threads and/or doesn't uses
many executable mmap operations.

Work is being planed to solve this situation, till then, this will
remain disabled by default.

Reported-by: David Miller &lt;davem@davemloft.net&gt;
Acked-by: Kan Liang &lt;kan.liang@intel.com&gt;
Link: https://lkml.kernel.org/r/4f84468f-37d9-cf1b-12c1-514ef74b6a48@linux.intel.com
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Fixes: ebebbf082357 ("perf top: Switch default mode to overwrite mode")
Link: https://lkml.kernel.org/n/tip-ehvf77vi1si9409r7p4wx788@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf top: Allow disabling the overwrite mode</title>
<updated>2018-10-30T14:46:23+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2018-10-26T18:55:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4e303fbe2d95806c875f5ebfcb3d980e20b4bd83'/>
<id>4e303fbe2d95806c875f5ebfcb3d980e20b4bd83</id>
<content type='text'>
In ebebbf082357 ("perf top: Switch default mode to overwrite mode") we
forgot to leave a way to disable that new default, add a --overwrite
option that can be disabled using --no-overwrite, since the code already
in such a way that we can readily disable this mode.

This is useful when investigating bugs with this mode like the recent
report from David Miller where lots of unknown symbols appear due to
disabling the events while processing them which disables all record
types, not just PERF_RECORD_SAMPLE, which makes it impossible to resolve
maps when we lose PERF_RECORD_MMAP records.

This can be easily seen while building a kernel, when there are lots of
short lived processes.

Reported-by: David Miller &lt;davem@davemloft.net&gt;
Acked-by: Kan Liang &lt;kan.liang@intel.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&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;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Fixes: ebebbf082357 ("perf top: Switch default mode to overwrite mode")
Link: https://lkml.kernel.org/n/tip-oqgsz2bq4kgrnnajrafcdhie@git.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>
In ebebbf082357 ("perf top: Switch default mode to overwrite mode") we
forgot to leave a way to disable that new default, add a --overwrite
option that can be disabled using --no-overwrite, since the code already
in such a way that we can readily disable this mode.

This is useful when investigating bugs with this mode like the recent
report from David Miller where lots of unknown symbols appear due to
disabling the events while processing them which disables all record
types, not just PERF_RECORD_SAMPLE, which makes it impossible to resolve
maps when we lose PERF_RECORD_MMAP records.

This can be easily seen while building a kernel, when there are lots of
short lived processes.

Reported-by: David Miller &lt;davem@davemloft.net&gt;
Acked-by: Kan Liang &lt;kan.liang@intel.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&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;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Fixes: ebebbf082357 ("perf top: Switch default mode to overwrite mode")
Link: https://lkml.kernel.org/n/tip-oqgsz2bq4kgrnnajrafcdhie@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf script: Implement --graph-function</title>
<updated>2018-10-24T18:29:55+00:00</updated>
<author>
<name>Andi Kleen</name>
<email>ak@linux.intel.com</email>
</author>
<published>2018-09-20T18:05:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=99f753f048b3f02f31a56951781672021af6cd0d'/>
<id>99f753f048b3f02f31a56951781672021af6cd0d</id>
<content type='text'>
Add a ftrace style --graph-function argument to 'perf script' that
allows to print itrace function calls only below a given function. This
makes it easier to find the code of interest in a large trace.

% perf record -e intel_pt//k -a sleep 1
% perf script --graph-function group_sched_in --call-trace
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])          group_sched_in
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])              __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])              event_sched_in.isra.107
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_event_set_state.part.71
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                      perf_event_update_time
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_pmu_disable
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_log_itrace_start
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                      perf_event_update_userpage
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                          calc_timer_values
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                              sched_clock_cpu
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                          __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                          arch_perf_update_userpage
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                              __fentry__
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                              using_native_sched_clock
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                              sched_clock_stable
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_pmu_enable
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])              __x86_indirect_thunk_rax
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])          group_sched_in
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])              __x86_indirect_thunk_rax
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])              event_sched_in.isra.107
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                  perf_event_set_state.part.71
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                      perf_event_update_time
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                  perf_pmu_disable
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                  perf_log_itrace_start
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                  __x86_indirect_thunk_rax
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                      perf_event_update_userpage
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                          calc_timer_values
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                              sched_clock_cpu
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                          __x86_indirect_thunk_rax
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                          arch_perf_update_userpage
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                              __fentry__
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                              using_native_sched_clock
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                              sched_clock_stable

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Tested-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kim Phillips &lt;kim.phillips@arm.com&gt;
Link: http://lkml.kernel.org/r/20180920180540.14039-5-andi@firstfloor.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>
Add a ftrace style --graph-function argument to 'perf script' that
allows to print itrace function calls only below a given function. This
makes it easier to find the code of interest in a large trace.

% perf record -e intel_pt//k -a sleep 1
% perf script --graph-function group_sched_in --call-trace
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])          group_sched_in
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])              __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])              event_sched_in.isra.107
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_event_set_state.part.71
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                      perf_event_update_time
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_pmu_disable
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_log_itrace_start
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                      perf_event_update_userpage
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                          calc_timer_values
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                              sched_clock_cpu
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                          __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                          arch_perf_update_userpage
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                              __fentry__
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                              using_native_sched_clock
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                              sched_clock_stable
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_pmu_enable
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])              __x86_indirect_thunk_rax
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])          group_sched_in
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])              __x86_indirect_thunk_rax
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])              event_sched_in.isra.107
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                  perf_event_set_state.part.71
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                      perf_event_update_time
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                  perf_pmu_disable
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                  perf_log_itrace_start
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                  __x86_indirect_thunk_rax
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                      perf_event_update_userpage
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                          calc_timer_values
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                              sched_clock_cpu
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                          __x86_indirect_thunk_rax
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                          arch_perf_update_userpage
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                              __fentry__
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                              using_native_sched_clock
         swapper     0 [001] 194167.205660693: ([kernel.kallsyms])                              sched_clock_stable

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Tested-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kim Phillips &lt;kim.phillips@arm.com&gt;
Link: http://lkml.kernel.org/r/20180920180540.14039-5-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tools script: Add --call-trace and --call-ret-trace</title>
<updated>2018-10-24T18:29:55+00:00</updated>
<author>
<name>Andi Kleen</name>
<email>ak@linux.intel.com</email>
</author>
<published>2018-09-20T18:05:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d1b1552e15d41297abcaf3812378e3391d44fa6b'/>
<id>d1b1552e15d41297abcaf3812378e3391d44fa6b</id>
<content type='text'>
Add short cut options to print PT call trace and call-ret-trace, for
calls and call and returns. Roughly corresponds to ftrace function
tracer and function graph tracer.

Just makes these common use cases nicer to use.

% perf record -a -e intel_pt// sleep 1
% perf script --call-trace
	    perf   900 [000] 194167.205652203: ([kernel.kallsyms])          perf_pmu_enable
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])          __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])          event_filter_match
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])          group_sched_in
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])              __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])              event_sched_in.isra.107
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_event_set_state.part.71
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                      perf_event_update_time
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_pmu_disable
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_log_itrace_start
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                      perf_event_update_userpage

% perf script --call-ret-trace
	    perf   900 [000] 194167.205652203:   tr strt     ([unknown])        pt_config
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            pt_config
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            pt_event_add
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])            perf_pmu_enable
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            perf_pmu_nop_void
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            event_sched_in.isra.107
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])            __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            perf_pmu_nop_int
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            group_sched_in
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])            event_filter_match
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            event_filter_match
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])            group_sched_in
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])                __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])                perf_pmu_nop_txn
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])                event_sched_in.isra.107
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])                    perf_event_set_state.part.71

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Tested-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kim Phillips &lt;kim.phillips@arm.com&gt;
Link: http://lkml.kernel.org/r/20180920180540.14039-4-andi@firstfloor.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>
Add short cut options to print PT call trace and call-ret-trace, for
calls and call and returns. Roughly corresponds to ftrace function
tracer and function graph tracer.

Just makes these common use cases nicer to use.

% perf record -a -e intel_pt// sleep 1
% perf script --call-trace
	    perf   900 [000] 194167.205652203: ([kernel.kallsyms])          perf_pmu_enable
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])          __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])          event_filter_match
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])          group_sched_in
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])              __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])              event_sched_in.isra.107
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_event_set_state.part.71
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                      perf_event_update_time
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_pmu_disable
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  perf_log_itrace_start
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                  __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203: ([kernel.kallsyms])                      perf_event_update_userpage

% perf script --call-ret-trace
	    perf   900 [000] 194167.205652203:   tr strt     ([unknown])        pt_config
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            pt_config
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            pt_event_add
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])            perf_pmu_enable
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            perf_pmu_nop_void
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            event_sched_in.isra.107
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])            __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            perf_pmu_nop_int
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            group_sched_in
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])            event_filter_match
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])            event_filter_match
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])            group_sched_in
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])                __x86_indirect_thunk_rax
            perf   900 [000] 194167.205652203:   return      ([kernel.kallsyms])                perf_pmu_nop_txn
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])                event_sched_in.isra.107
            perf   900 [000] 194167.205652203:   call        ([kernel.kallsyms])                    perf_event_set_state.part.71

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Tested-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kim Phillips &lt;kim.phillips@arm.com&gt;
Link: http://lkml.kernel.org/r/20180920180540.14039-4-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf script: Make itrace script default to all calls</title>
<updated>2018-10-24T18:29:54+00:00</updated>
<author>
<name>Andi Kleen</name>
<email>ak@linux.intel.com</email>
</author>
<published>2018-09-20T18:05:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4eb068157121939f4bc16256a37bcd88f5554123'/>
<id>4eb068157121939f4bc16256a37bcd88f5554123</id>
<content type='text'>
By default 'perf script' for itrace outputs sampled instructions or
branches. In my experience this is confusing to users because it's hard
to correlate with real program behavior. The sampling makes sense for
tools like 'perf report' that actually sample to reduce the run time,
but run time is normally not a problem for 'perf script'.  It's better
to give an accurate representation of the program flow.

Default 'perf script' to output all calls for itrace. That's a much saner
default. The old behavior can be still requested with 'perf script'
--itrace=ibxwpe100000

v2: Fix ETM build failure
v3: Really fix ETM build failure (Kim Phillips)

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kim Phillips &lt;kim.phillips@arm.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Link: http://lkml.kernel.org/r/20180920180540.14039-3-andi@firstfloor.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>
By default 'perf script' for itrace outputs sampled instructions or
branches. In my experience this is confusing to users because it's hard
to correlate with real program behavior. The sampling makes sense for
tools like 'perf report' that actually sample to reduce the run time,
but run time is normally not a problem for 'perf script'.  It's better
to give an accurate representation of the program flow.

Default 'perf script' to output all calls for itrace. That's a much saner
default. The old behavior can be still requested with 'perf script'
--itrace=ibxwpe100000

v2: Fix ETM build failure
v3: Really fix ETM build failure (Kim Phillips)

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kim Phillips &lt;kim.phillips@arm.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Link: http://lkml.kernel.org/r/20180920180540.14039-3-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf script: Add --insn-trace for instruction decoding</title>
<updated>2018-10-24T18:29:50+00:00</updated>
<author>
<name>Andi Kleen</name>
<email>ak@linux.intel.com</email>
</author>
<published>2018-09-20T18:05:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b585ebdb5912cf1438d4822f79aaebe36a2d123a'/>
<id>b585ebdb5912cf1438d4822f79aaebe36a2d123a</id>
<content type='text'>
Add a --insn-trace short hand option for decoding and disassembling
instruction streams for intel_pt. This automatically pipes the output
into the xed disassembler to generate disassembled instructions.  This
just makes this use model much nicer to use.

Before

  % perf record -e intel_pt// ...
  % perf script --itrace=i0ns --ns -F +insn,-event,-period | xed -F insn: -A -64
   swapper 0 [000] 17276.429606186: ffffffff81010486 pt_config ([kernel.kallsyms])    nopl  %eax, (%rax,%rax,1)
   swapper 0 [000] 17276.429606186: ffffffff8101048b pt_config ([kernel.kallsyms])    add $0x10, %rsp
   swapper 0 [000] 17276.429606186: ffffffff8101048f pt_config ([kernel.kallsyms])    popq  %rbx
   swapper 0 [000] 17276.429606186: ffffffff81010490 pt_config ([kernel.kallsyms])    popq  %rbp
   swapper 0 [000] 17276.429606186: ffffffff81010491 pt_config ([kernel.kallsyms])    popq  %r12
   swapper 0 [000] 17276.429606186: ffffffff81010493 pt_config ([kernel.kallsyms])    popq  %r13
   swapper 0 [000] 17276.429606186: ffffffff81010495 pt_config ([kernel.kallsyms])    popq  %r14
   swapper 0 [000] 17276.429606186: ffffffff81010497 pt_config ([kernel.kallsyms])    popq  %r15
   swapper 0 [000] 17276.429606186: ffffffff81010499 pt_config ([kernel.kallsyms])    retq
   swapper 0 [000] 17276.429606186: ffffffff8101063e pt_event_add ([kernel.kallsyms])         cmpl  $0x1, 0x1b0(%rbx)
   swapper 0 [000] 17276.429606186: ffffffff81010645 pt_event_add ([kernel.kallsyms])         mov $0xffffffea, %eax
   swapper 0 [000] 17276.429606186: ffffffff8101064a pt_event_add ([kernel.kallsyms])         mov $0x0, %edx
   swapper 0 [000] 17276.429606186: ffffffff8101064f pt_event_add ([kernel.kallsyms])         popq  %rbx
   swapper 0 [000] 17276.429606186: ffffffff81010650 pt_event_add ([kernel.kallsyms])         cmovnz %edx, %eax
   swapper 0 [000] 17276.429606186: ffffffff81010653 pt_event_add ([kernel.kallsyms])         jmp 0xffffffff81010635
   swapper 0 [000] 17276.429606186: ffffffff81010635 pt_event_add ([kernel.kallsyms])         retq
   swapper 0 [000] 17276.429606186: ffffffff8115e687 event_sched_in.isra.107 ([kernel.kallsyms])       test %eax, %eax

Now:

  % perf record -e intel_pt// ...
  % perf script --insn-trace --xed
  ... same output ...

XED needs to be installed with:

  $ git clone https://github.com/intelxed/mbuild.git mbuild
  $ git clone https://github.com/intelxed/xed
  $ cd xed
  $ ./mfile.py
  $ ./mfile.py examples
  $ sudo ./mfile.py --prefix=/usr/local install
  $ sudo cp obj/examples/xed /usr/local/bin
  $ xed | head -3
  ERROR: required argument(s) were missing
  Copyright (C) 2017, Intel Corporation. All rights reserved.
  XED version: [v10.0-328-g7d62c8c49b7b]
  $

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: http://lkml.kernel.org/r/20180920180540.14039-2-andi@firstfloor.org
[ Fixed up whitespace damage, added the 'mfile.py examples + cp obj/examples/xed ... ]
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 a --insn-trace short hand option for decoding and disassembling
instruction streams for intel_pt. This automatically pipes the output
into the xed disassembler to generate disassembled instructions.  This
just makes this use model much nicer to use.

Before

  % perf record -e intel_pt// ...
  % perf script --itrace=i0ns --ns -F +insn,-event,-period | xed -F insn: -A -64
   swapper 0 [000] 17276.429606186: ffffffff81010486 pt_config ([kernel.kallsyms])    nopl  %eax, (%rax,%rax,1)
   swapper 0 [000] 17276.429606186: ffffffff8101048b pt_config ([kernel.kallsyms])    add $0x10, %rsp
   swapper 0 [000] 17276.429606186: ffffffff8101048f pt_config ([kernel.kallsyms])    popq  %rbx
   swapper 0 [000] 17276.429606186: ffffffff81010490 pt_config ([kernel.kallsyms])    popq  %rbp
   swapper 0 [000] 17276.429606186: ffffffff81010491 pt_config ([kernel.kallsyms])    popq  %r12
   swapper 0 [000] 17276.429606186: ffffffff81010493 pt_config ([kernel.kallsyms])    popq  %r13
   swapper 0 [000] 17276.429606186: ffffffff81010495 pt_config ([kernel.kallsyms])    popq  %r14
   swapper 0 [000] 17276.429606186: ffffffff81010497 pt_config ([kernel.kallsyms])    popq  %r15
   swapper 0 [000] 17276.429606186: ffffffff81010499 pt_config ([kernel.kallsyms])    retq
   swapper 0 [000] 17276.429606186: ffffffff8101063e pt_event_add ([kernel.kallsyms])         cmpl  $0x1, 0x1b0(%rbx)
   swapper 0 [000] 17276.429606186: ffffffff81010645 pt_event_add ([kernel.kallsyms])         mov $0xffffffea, %eax
   swapper 0 [000] 17276.429606186: ffffffff8101064a pt_event_add ([kernel.kallsyms])         mov $0x0, %edx
   swapper 0 [000] 17276.429606186: ffffffff8101064f pt_event_add ([kernel.kallsyms])         popq  %rbx
   swapper 0 [000] 17276.429606186: ffffffff81010650 pt_event_add ([kernel.kallsyms])         cmovnz %edx, %eax
   swapper 0 [000] 17276.429606186: ffffffff81010653 pt_event_add ([kernel.kallsyms])         jmp 0xffffffff81010635
   swapper 0 [000] 17276.429606186: ffffffff81010635 pt_event_add ([kernel.kallsyms])         retq
   swapper 0 [000] 17276.429606186: ffffffff8115e687 event_sched_in.isra.107 ([kernel.kallsyms])       test %eax, %eax

Now:

  % perf record -e intel_pt// ...
  % perf script --insn-trace --xed
  ... same output ...

XED needs to be installed with:

  $ git clone https://github.com/intelxed/mbuild.git mbuild
  $ git clone https://github.com/intelxed/xed
  $ cd xed
  $ ./mfile.py
  $ ./mfile.py examples
  $ sudo ./mfile.py --prefix=/usr/local install
  $ sudo cp obj/examples/xed /usr/local/bin
  $ xed | head -3
  ERROR: required argument(s) were missing
  Copyright (C) 2017, Intel Corporation. All rights reserved.
  XED version: [v10.0-328-g7d62c8c49b7b]
  $

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: http://lkml.kernel.org/r/20180920180540.14039-2-andi@firstfloor.org
[ Fixed up whitespace damage, added the 'mfile.py examples + cp obj/examples/xed ... ]
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf scripts python: call-graph-from-sql.py: Rename to exported-sql-viewer.py</title>
<updated>2018-10-23T17:26:44+00:00</updated>
<author>
<name>Adrian Hunter</name>
<email>adrian.hunter@intel.com</email>
</author>
<published>2018-10-01T06:28:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=031c2a004ba75a4f8f2a6d0a7ca6f2fe5912de22'/>
<id>031c2a004ba75a4f8f2a6d0a7ca6f2fe5912de22</id>
<content type='text'>
Additional reports will be added to the script so rename to reflect the
more general purpose.

Signed-off-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Link: http://lkml.kernel.org/r/20181001062853.28285-13-adrian.hunter@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>
Additional reports will be added to the script so rename to reflect the
more general purpose.

Signed-off-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Link: http://lkml.kernel.org/r/20181001062853.28285-13-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf trace: Introduce per-event maximum number of events property</title>
<updated>2018-10-22T17:27:12+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2018-10-22T17:14:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a9c5e6c1e9bff42ca5f01ceb3092a27a010755fb'/>
<id>a9c5e6c1e9bff42ca5f01ceb3092a27a010755fb</id>
<content type='text'>
Call it 'nr', as in this context it should be expressive enough, i.e.:

  # perf trace -e sched:*waking/nr=8,call-graph=fp/
     0.000 :0/0 sched:sched_waking:comm=rcu_sched pid=10 prio=120 target_cpu=001
                                       try_to_wake_up ([kernel.kallsyms])
                                       sched_clock ([kernel.kallsyms])
     3.933 :0/0 sched:sched_waking:comm=rcu_sched pid=10 prio=120 target_cpu=001
                                       try_to_wake_up ([kernel.kallsyms])
                                       sched_clock ([kernel.kallsyms])
     3.970 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    20.069 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    37.170 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    53.267 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    70.365 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    75.781 Web Content/3649 sched:sched_waking:comm=JS Helper pid=3670 prio=120 target_cpu=000
                                       try_to_wake_up ([kernel.kallsyms])
                                       try_to_wake_up ([kernel.kallsyms])
                                       wake_up_q ([kernel.kallsyms])
                                       futex_wake ([kernel.kallsyms])
                                       do_futex ([kernel.kallsyms])
                                       __x64_sys_futex ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
                                       pthread_cond_signal@@GLIBC_2.3.2 (/usr/lib64/libpthread-2.26.so)
  #

  # perf trace -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/
     0.000 :0/0 sched:sched_switch:swapper/0:0 [120] S ==&gt; trace:3367 [120]
     0.046 :0/0 sched:sched_switch:swapper/1:0 [120] S ==&gt; kworker/u16:58:2722 [120]
   570.670 irq/50-iwlwifi/680 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051ef00 len=66
                                       __dev_queue_xmit ([kernel.kallsyms])
  1106.141 jbd2/dm-0-8/476 block:block_plug:[jbd2/dm-0-8]
  1106.175 jbd2/dm-0-8/476 block:block_unplug:[jbd2/dm-0-8] 1
  1618.088 kworker/u16:30/2694 block:block_plug:[kworker/u16:30]
  1810.000 :0/0 net:net_dev_queue:dev=vnet0 skbaddr=0xffff93498051ef00 len=52
                                       __dev_queue_xmit ([kernel.kallsyms])
  3857.974 :0/0 net:net_dev_queue:dev=vnet0 skbaddr=0xffff93498051f900 len=52
                                       __dev_queue_xmit ([kernel.kallsyms])
  4790.277 jbd2/dm-2-8/748 block:block_plug:[jbd2/dm-2-8]
  4790.448 jbd2/dm-2-8/748 block:block_plug:[jbd2/dm-2-8]
  #

The global --max-events has precendence:

  # trace --max-events 3 -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/
     0.000 :0/0 sched:sched_switch:swapper/0:0 [120] S ==&gt; qemu-system-x86:2252 [120]
     0.029 qemu-system-x8/2252 sched:sched_switch:qemu-system-x86:2252 [120] D ==&gt; swapper/0:0 [120]
    58.047 DNS Res~er #14/31661 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff9346966af100 len=84
                                       __dev_queue_xmit ([kernel.kallsyms])
                                       __libc_send (/usr/lib64/libpthread-2.26.so)
  #

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: https://lkml.kernel.org/n/tip-s4jswltvh660ughvg9nwngah@git.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>
Call it 'nr', as in this context it should be expressive enough, i.e.:

  # perf trace -e sched:*waking/nr=8,call-graph=fp/
     0.000 :0/0 sched:sched_waking:comm=rcu_sched pid=10 prio=120 target_cpu=001
                                       try_to_wake_up ([kernel.kallsyms])
                                       sched_clock ([kernel.kallsyms])
     3.933 :0/0 sched:sched_waking:comm=rcu_sched pid=10 prio=120 target_cpu=001
                                       try_to_wake_up ([kernel.kallsyms])
                                       sched_clock ([kernel.kallsyms])
     3.970 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    20.069 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    37.170 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    53.267 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    70.365 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    75.781 Web Content/3649 sched:sched_waking:comm=JS Helper pid=3670 prio=120 target_cpu=000
                                       try_to_wake_up ([kernel.kallsyms])
                                       try_to_wake_up ([kernel.kallsyms])
                                       wake_up_q ([kernel.kallsyms])
                                       futex_wake ([kernel.kallsyms])
                                       do_futex ([kernel.kallsyms])
                                       __x64_sys_futex ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
                                       pthread_cond_signal@@GLIBC_2.3.2 (/usr/lib64/libpthread-2.26.so)
  #

  # perf trace -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/
     0.000 :0/0 sched:sched_switch:swapper/0:0 [120] S ==&gt; trace:3367 [120]
     0.046 :0/0 sched:sched_switch:swapper/1:0 [120] S ==&gt; kworker/u16:58:2722 [120]
   570.670 irq/50-iwlwifi/680 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051ef00 len=66
                                       __dev_queue_xmit ([kernel.kallsyms])
  1106.141 jbd2/dm-0-8/476 block:block_plug:[jbd2/dm-0-8]
  1106.175 jbd2/dm-0-8/476 block:block_unplug:[jbd2/dm-0-8] 1
  1618.088 kworker/u16:30/2694 block:block_plug:[kworker/u16:30]
  1810.000 :0/0 net:net_dev_queue:dev=vnet0 skbaddr=0xffff93498051ef00 len=52
                                       __dev_queue_xmit ([kernel.kallsyms])
  3857.974 :0/0 net:net_dev_queue:dev=vnet0 skbaddr=0xffff93498051f900 len=52
                                       __dev_queue_xmit ([kernel.kallsyms])
  4790.277 jbd2/dm-2-8/748 block:block_plug:[jbd2/dm-2-8]
  4790.448 jbd2/dm-2-8/748 block:block_plug:[jbd2/dm-2-8]
  #

The global --max-events has precendence:

  # trace --max-events 3 -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/
     0.000 :0/0 sched:sched_switch:swapper/0:0 [120] S ==&gt; qemu-system-x86:2252 [120]
     0.029 qemu-system-x8/2252 sched:sched_switch:qemu-system-x86:2252 [120] D ==&gt; swapper/0:0 [120]
    58.047 DNS Res~er #14/31661 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff9346966af100 len=84
                                       __dev_queue_xmit ([kernel.kallsyms])
                                       __libc_send (/usr/lib64/libpthread-2.26.so)
  #

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: https://lkml.kernel.org/n/tip-s4jswltvh660ughvg9nwngah@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf trace: Introduce --max-events</title>
<updated>2018-10-19T14:58:33+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2018-10-18T19:38:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5067a8cdd4ce3588fca2e0ee554f0f081650de8f'/>
<id>5067a8cdd4ce3588fca2e0ee554f0f081650de8f</id>
<content type='text'>
Allow stopping tracing after a number of events take place, considering
strace-like syscalls formatting as one event per enter/exit pair or when
in a multi-process tracing session a syscall is interrupted and printed
ending with '...'.

Examples included in the documentation:

Trace the first 4 open, openat or open_by_handle_at syscalls (in the future more syscalls may match here):

  $ perf trace -e open* --max-events 4
  [root@jouet perf]# trace -e open* --max-events 4
  2272.992 ( 0.037 ms): gnome-shell/1370 openat(dfd: CWD, filename: /proc/self/stat) = 31
  2277.481 ( 0.139 ms): gnome-shell/3039 openat(dfd: CWD, filename: /proc/self/stat) = 65
  3026.398 ( 0.076 ms): gnome-shell/3039 openat(dfd: CWD, filename: /proc/self/stat) = 65
  4294.665 ( 0.015 ms): sed/15879 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC) = 3
  $

Trace the first minor page fault when running a workload:

  # perf trace -F min --max-stack=7 --max-events 1 sleep 1
     0.000 ( 0.000 ms): sleep/18006 minfault [__clear_user+0x1a] =&gt; 0x5626efa56080 (?k)
                                       __clear_user ([kernel.kallsyms])
                                       load_elf_binary ([kernel.kallsyms])
                                       search_binary_handler ([kernel.kallsyms])
                                       __do_execve_file.isra.33 ([kernel.kallsyms])
                                       __x64_sys_execve ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64 ([kernel.kallsyms])
  #

Trace the next min page page fault to take place on the first CPU:

  # perf trace -F min --call-graph=dwarf --max-events 1 --cpu 0
     0.000 ( 0.000 ms): Web Content/17136 minfault [js::gc::Chunk::fetchNextDecommittedArena+0x4b] =&gt; 0x7fbe6181b000 (?.)
                                       js::gc::FreeSpan::initAsEmpty (inlined)
                                       js::gc::Arena::setAsNotAllocated (inlined)
                                       js::gc::Chunk::fetchNextDecommittedArena (/usr/lib64/firefox/libxul.so)
                                       js::gc::Chunk::allocateArena (/usr/lib64/firefox/libxul.so)
                                       js::gc::GCRuntime::allocateArena (/usr/lib64/firefox/libxul.so)
                                       js::gc::ArenaLists::allocateFromArena (/usr/lib64/firefox/libxul.so)
                                       js::gc::GCRuntime::tryNewTenuredThing&lt;JSString, (js::AllowGC)1&gt; (inlined)
                                       js::AllocateString&lt;JSString, (js::AllowGC)1&gt; (/usr/lib64/firefox/libxul.so)
                                       js::Allocate&lt;JSThinInlineString, (js::AllowGC)1&gt; (inlined)
                                       JSThinInlineString::new_&lt;(js::AllowGC)1&gt; (inlined)
                                       AllocateInlineString&lt;(js::AllowGC)1, unsigned char&gt; (inlined)
                                       js::ConcatStrings&lt;(js::AllowGC)1&gt; (/usr/lib64/firefox/libxul.so)
                                       [0x18b26e6bc2bd] (/tmp/perf-17136.map)

Tracing the next four ext4 operations on a specific CPU:

  # perf trace -e ext4:*/call-graph=fp/ --max-events 4 --cpu 3
     0.000 mutt/3849 ext4:ext4_es_lookup_extent_enter:dev 253,2 ino 57277 lblk 0
                                       ext4_es_lookup_extent ([kernel.kallsyms])
                                       read (/usr/lib64/libc-2.26.so)
     0.097 mutt/3849 ext4:ext4_es_lookup_extent_exit:dev 253,2 ino 57277 found 0 [0/0) 0
                                       ext4_es_lookup_extent ([kernel.kallsyms])
                                       read (/usr/lib64/libc-2.26.so)
     0.141 mutt/3849 ext4:ext4_ext_map_blocks_enter:dev 253,2 ino 57277 lblk 0 len 1 flags
                                       ext4_ext_map_blocks ([kernel.kallsyms])
                                       read (/usr/lib64/libc-2.26.so)
     0.184 mutt/3849 ext4:ext4_ext_load_extent:dev 253,2 ino 57277 lblk 1516511 pblk 18446744071750013657
                                       __read_extent_tree_block ([kernel.kallsyms])
                                       __read_extent_tree_block ([kernel.kallsyms])
                                       ext4_find_extent ([kernel.kallsyms])
                                       ext4_ext_map_blocks ([kernel.kallsyms])
                                       ext4_map_blocks ([kernel.kallsyms])
                                       ext4_mpage_readpages ([kernel.kallsyms])
                                       read_pages ([kernel.kallsyms])
                                       __do_page_cache_readahead ([kernel.kallsyms])
                                       ondemand_readahead ([kernel.kallsyms])
                                       generic_file_read_iter ([kernel.kallsyms])
                                       __vfs_read ([kernel.kallsyms])
                                       vfs_read ([kernel.kallsyms])
                                       ksys_read ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64 ([kernel.kallsyms])
                                       read (/usr/lib64/libc-2.26.so)
  #

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Milian Wolff &lt;milian.wolff@kdab.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Rudá Moura &lt;ruda.moura@gmail.com&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: https://lkml.kernel.org/n/tip-sweh107bs7ol5bzls0m4tqdz@git.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>
Allow stopping tracing after a number of events take place, considering
strace-like syscalls formatting as one event per enter/exit pair or when
in a multi-process tracing session a syscall is interrupted and printed
ending with '...'.

Examples included in the documentation:

Trace the first 4 open, openat or open_by_handle_at syscalls (in the future more syscalls may match here):

  $ perf trace -e open* --max-events 4
  [root@jouet perf]# trace -e open* --max-events 4
  2272.992 ( 0.037 ms): gnome-shell/1370 openat(dfd: CWD, filename: /proc/self/stat) = 31
  2277.481 ( 0.139 ms): gnome-shell/3039 openat(dfd: CWD, filename: /proc/self/stat) = 65
  3026.398 ( 0.076 ms): gnome-shell/3039 openat(dfd: CWD, filename: /proc/self/stat) = 65
  4294.665 ( 0.015 ms): sed/15879 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC) = 3
  $

Trace the first minor page fault when running a workload:

  # perf trace -F min --max-stack=7 --max-events 1 sleep 1
     0.000 ( 0.000 ms): sleep/18006 minfault [__clear_user+0x1a] =&gt; 0x5626efa56080 (?k)
                                       __clear_user ([kernel.kallsyms])
                                       load_elf_binary ([kernel.kallsyms])
                                       search_binary_handler ([kernel.kallsyms])
                                       __do_execve_file.isra.33 ([kernel.kallsyms])
                                       __x64_sys_execve ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64 ([kernel.kallsyms])
  #

Trace the next min page page fault to take place on the first CPU:

  # perf trace -F min --call-graph=dwarf --max-events 1 --cpu 0
     0.000 ( 0.000 ms): Web Content/17136 minfault [js::gc::Chunk::fetchNextDecommittedArena+0x4b] =&gt; 0x7fbe6181b000 (?.)
                                       js::gc::FreeSpan::initAsEmpty (inlined)
                                       js::gc::Arena::setAsNotAllocated (inlined)
                                       js::gc::Chunk::fetchNextDecommittedArena (/usr/lib64/firefox/libxul.so)
                                       js::gc::Chunk::allocateArena (/usr/lib64/firefox/libxul.so)
                                       js::gc::GCRuntime::allocateArena (/usr/lib64/firefox/libxul.so)
                                       js::gc::ArenaLists::allocateFromArena (/usr/lib64/firefox/libxul.so)
                                       js::gc::GCRuntime::tryNewTenuredThing&lt;JSString, (js::AllowGC)1&gt; (inlined)
                                       js::AllocateString&lt;JSString, (js::AllowGC)1&gt; (/usr/lib64/firefox/libxul.so)
                                       js::Allocate&lt;JSThinInlineString, (js::AllowGC)1&gt; (inlined)
                                       JSThinInlineString::new_&lt;(js::AllowGC)1&gt; (inlined)
                                       AllocateInlineString&lt;(js::AllowGC)1, unsigned char&gt; (inlined)
                                       js::ConcatStrings&lt;(js::AllowGC)1&gt; (/usr/lib64/firefox/libxul.so)
                                       [0x18b26e6bc2bd] (/tmp/perf-17136.map)

Tracing the next four ext4 operations on a specific CPU:

  # perf trace -e ext4:*/call-graph=fp/ --max-events 4 --cpu 3
     0.000 mutt/3849 ext4:ext4_es_lookup_extent_enter:dev 253,2 ino 57277 lblk 0
                                       ext4_es_lookup_extent ([kernel.kallsyms])
                                       read (/usr/lib64/libc-2.26.so)
     0.097 mutt/3849 ext4:ext4_es_lookup_extent_exit:dev 253,2 ino 57277 found 0 [0/0) 0
                                       ext4_es_lookup_extent ([kernel.kallsyms])
                                       read (/usr/lib64/libc-2.26.so)
     0.141 mutt/3849 ext4:ext4_ext_map_blocks_enter:dev 253,2 ino 57277 lblk 0 len 1 flags
                                       ext4_ext_map_blocks ([kernel.kallsyms])
                                       read (/usr/lib64/libc-2.26.so)
     0.184 mutt/3849 ext4:ext4_ext_load_extent:dev 253,2 ino 57277 lblk 1516511 pblk 18446744071750013657
                                       __read_extent_tree_block ([kernel.kallsyms])
                                       __read_extent_tree_block ([kernel.kallsyms])
                                       ext4_find_extent ([kernel.kallsyms])
                                       ext4_ext_map_blocks ([kernel.kallsyms])
                                       ext4_map_blocks ([kernel.kallsyms])
                                       ext4_mpage_readpages ([kernel.kallsyms])
                                       read_pages ([kernel.kallsyms])
                                       __do_page_cache_readahead ([kernel.kallsyms])
                                       ondemand_readahead ([kernel.kallsyms])
                                       generic_file_read_iter ([kernel.kallsyms])
                                       __vfs_read ([kernel.kallsyms])
                                       vfs_read ([kernel.kallsyms])
                                       ksys_read ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64 ([kernel.kallsyms])
                                       read (/usr/lib64/libc-2.26.so)
  #

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Milian Wolff &lt;milian.wolff@kdab.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Rudá Moura &lt;ruda.moura@gmail.com&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: https://lkml.kernel.org/n/tip-sweh107bs7ol5bzls0m4tqdz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
