<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/tools/perf/util/evsel.h, branch linux-5.2.y</title>
<subtitle>Hosts the 0x221E linux distro kernel.</subtitle>
<id>https://universe.0xinfinity.dev/distro/kernel/atom?h=linux-5.2.y</id>
<link rel='self' href='https://universe.0xinfinity.dev/distro/kernel/atom?h=linux-5.2.y'/>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/'/>
<updated>2019-05-16T17:17:24Z</updated>
<entry>
<title>perf tools: Add a 'percore' event qualifier</title>
<updated>2019-05-16T17:17:24Z</updated>
<author>
<name>Jin Yao</name>
<email>yao.jin@linux.intel.com</email>
</author>
<published>2019-04-12T13:59:47Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=064b4e82aa1633c27c383cc686b87ced57e072d1'/>
<id>urn:sha1:064b4e82aa1633c27c383cc686b87ced57e072d1</id>
<content type='text'>
Add a 'percore' event qualifier, like cpu/event=0,umask=0x3,percore=1/,
that sums up the event counts for both hardware threads in a core.

We can already do this with --per-core, but it's often useful to do
this together with other metrics that are collected per hardware thread.
So we need to support this per-core counting on a event level.

This can be implemented in only the user tool, no kernel support needed.

 v4:
 ---
 1. Add Arnaldo's patch which updates the documentation for
    this new qualifier.
 2. Rebase to latest perf/core branch

 v3:
 ---
 Simplify the code according to Jiri's comments.
 Before:
   "return term-&gt;val.percore ? true : false;"
 Now:
   "return term-&gt;val.percore;"

 v2:
 ---
 Change the qualifier name from 'coresum' to 'percore' according to
 comments from Jiri and Andi.

Signed-off-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Tested-by: Ravi Bangoria &lt;ravi.bangoria@linux.ibm.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@intel.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lkml.kernel.org/r/1555077590-27664-2-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf stat: Implement duration_time as a proper event</title>
<updated>2019-04-01T17:49:24Z</updated>
<author>
<name>Andi Kleen</name>
<email>ak@linux.intel.com</email>
</author>
<published>2019-03-26T22:18:21Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=f0fbb114e3025f3f737a1e1c5c39c5b2b2e671bd'/>
<id>urn:sha1:f0fbb114e3025f3f737a1e1c5c39c5b2b2e671bd</id>
<content type='text'>
The perf metric expression use 'duration_time' internally to normalize
events.  Normal 'perf stat' without -x also prints the duration time.
But when using -x, the interval is not output anywhere, which is
inconvenient for any post processing which often wants to normalize
values to time.

So implement 'duration_time' as a proper perf event that can be
specified explicitely with -e.

The previous implementation of 'duration_time' only worked for metric
processing. This adds the concept of a tool event that is handled by the
tool. On the kernel level it is still mapped to the dummy software
event, but the values are not read anymore, but instead computed by the
tool.

Add proper plumbing to handle this in the event parser, and display it
in 'perf stat'. We don't want 'duration_time' to be added up, so it's
only printed for the first CPU.

% perf stat -e duration_time,cycles true

 Performance counter stats for 'true':

           555,476 ns   duration_time
           771,958      cycles

       0.000555476 seconds time elapsed

       0.000644000 seconds user
       0.000000000 seconds sys

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/20190326221823.11518-3-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf evlist: Introduce side band thread</title>
<updated>2019-03-21T14:27:03Z</updated>
<author>
<name>Song Liu</name>
<email>songliubraving@fb.com</email>
</author>
<published>2019-03-12T05:30:50Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=657ee5531903339b06697581532ed32d4762526e'/>
<id>urn:sha1:657ee5531903339b06697581532ed32d4762526e</id>
<content type='text'>
This patch introduces side band thread that captures extended
information for events like PERF_RECORD_BPF_EVENT.

This new thread uses its own evlist that uses ring buffer with very low
watermark for lower latency.

To use side band thread, we need to:

1. add side band event(s) by calling perf_evlist__add_sb_event();
2. calls perf_evlist__start_sb_thread();
3. at the end of perf run, perf_evlist__stop_sb_thread().

In the next patch, we use this thread to handle PERF_RECORD_BPF_EVENT.

Committer notes:

Add fix by Jiri Olsa for when te sb_tread can't get started and then at
the end the stop_sb_thread() segfaults when joining the (non-existing)
thread.

That can happen when running 'perf top' or 'perf record' as a normal
user, for instance.

Further checks need to be done on top of this to more graciously handle
these possible failure scenarios.

Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stanislav Fomichev &lt;sdf@google.com&gt;
Link: http://lkml.kernel.org/r/20190312053051.2690567-15-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf evsel: No need to include symbol.h in evsel.h, symbol_conf.h is enough</title>
<updated>2019-02-06T13:00:38Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2019-01-27T23:06:16Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=9cd997f85e29c1c2b53e23fa98df7ec44c344d67'/>
<id>urn:sha1:9cd997f85e29c1c2b53e23fa98df7ec44c344d67</id>
<content type='text'>
To reduce the header dependency and avoid unnecessary rebuilds when
things change in symbol.h.

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lkml.kernel.org/n/tip-6duflwliprh2tr47w5x4t260@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tools: Handle PERF_RECORD_BPF_EVENT</title>
<updated>2019-01-21T20:00:57Z</updated>
<author>
<name>Song Liu</name>
<email>songliubraving@fb.com</email>
</author>
<published>2019-01-17T16:15:18Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=45178a928a4b7c6093f6621e627d09909e81cc13'/>
<id>urn:sha1:45178a928a4b7c6093f6621e627d09909e81cc13</id>
<content type='text'>
This patch adds basic handling of PERF_RECORD_BPF_EVENT.  Tracking of
PERF_RECORD_BPF_EVENT is OFF by default. Option --bpf-event is added to
turn it on.

Committer notes:

Add dummy machine__process_bpf_event() variant that returns zero for
systems without HAVE_LIBBPF_SUPPORT, such as Alpine Linux, unbreaking
the build in such systems.

Remove the needless include &lt;machine.h&gt; from bpf-&gt;event.h, provide just
forward declarations for the structs and unions in the parameters, to
reduce compilation time and needless rebuilds when machine.h gets
changed.

Committer testing:

When running with:

 # perf record --bpf-event

On an older kernel where PERF_RECORD_BPF_EVENT and PERF_RECORD_KSYMBOL
is not present, we fallback to removing those two bits from
perf_event_attr, making the tool to continue to work on older kernels:

  perf_event_attr:
    size                             112
    { sample_period, sample_freq }   4000
    sample_type                      IP|TID|TIME|PERIOD
    read_format                      ID
    disabled                         1
    inherit                          1
    mmap                             1
    comm                             1
    freq                             1
    enable_on_exec                   1
    task                             1
    precise_ip                       3
    sample_id_all                    1
    exclude_guest                    1
    mmap2                            1
    comm_exec                        1
    ksymbol                          1
    bpf_event                        1
  ------------------------------------------------------------
  sys_perf_event_open: pid 5779  cpu 0  group_fd -1  flags 0x8
  sys_perf_event_open failed, error -22
  switching off bpf_event
  ------------------------------------------------------------
  perf_event_attr:
    size                             112
    { sample_period, sample_freq }   4000
    sample_type                      IP|TID|TIME|PERIOD
    read_format                      ID
    disabled                         1
    inherit                          1
    mmap                             1
    comm                             1
    freq                             1
    enable_on_exec                   1
    task                             1
    precise_ip                       3
    sample_id_all                    1
    exclude_guest                    1
    mmap2                            1
    comm_exec                        1
    ksymbol                          1
  ------------------------------------------------------------
  sys_perf_event_open: pid 5779  cpu 0  group_fd -1  flags 0x8
  sys_perf_event_open failed, error -22
  switching off ksymbol
  ------------------------------------------------------------
  perf_event_attr:
    size                             112
    { sample_period, sample_freq }   4000
    sample_type                      IP|TID|TIME|PERIOD
    read_format                      ID
    disabled                         1
    inherit                          1
    mmap                             1
    comm                             1
    freq                             1
    enable_on_exec                   1
    task                             1
    precise_ip                       3
    sample_id_all                    1
    exclude_guest                    1
    mmap2                            1
    comm_exec                        1
  ------------------------------------------------------------

And then proceeds to work without those two features.

As passing --bpf-event is an explicit action performed by the user, perhaps we
should emit a warning telling that the kernel has no such feature, but this can
be done on top of this patch.

Now with a kernel that supports these events, start the 'record --bpf-event -a'
and then run 'perf trace sleep 10000' that will use the BPF
augmented_raw_syscalls.o prebuilt (for another kernel version even) and thus
should generate PERF_RECORD_BPF_EVENT events:

  [root@quaco ~]# perf record -e dummy -a --bpf-event
  ^C[ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.713 MB perf.data ]

  [root@quaco ~]# bpftool prog
  13: cgroup_skb  tag 7be49e3934a125ba  gpl
  	loaded_at 2019-01-19T09:09:43-0300  uid 0
  	xlated 296B  jited 229B  memlock 4096B  map_ids 13,14
  14: cgroup_skb  tag 2a142ef67aaad174  gpl
  	loaded_at 2019-01-19T09:09:43-0300  uid 0
  	xlated 296B  jited 229B  memlock 4096B  map_ids 13,14
  15: cgroup_skb  tag 7be49e3934a125ba  gpl
  	loaded_at 2019-01-19T09:09:43-0300  uid 0
  	xlated 296B  jited 229B  memlock 4096B  map_ids 15,16
  16: cgroup_skb  tag 2a142ef67aaad174  gpl
  	loaded_at 2019-01-19T09:09:43-0300  uid 0
  	xlated 296B  jited 229B  memlock 4096B  map_ids 15,16
  17: cgroup_skb  tag 7be49e3934a125ba  gpl
  	loaded_at 2019-01-19T09:09:44-0300  uid 0
  	xlated 296B  jited 229B  memlock 4096B  map_ids 17,18
  18: cgroup_skb  tag 2a142ef67aaad174  gpl
  	loaded_at 2019-01-19T09:09:44-0300  uid 0
  	xlated 296B  jited 229B  memlock 4096B  map_ids 17,18
  21: cgroup_skb  tag 7be49e3934a125ba  gpl
  	loaded_at 2019-01-19T09:09:45-0300  uid 0
  	xlated 296B  jited 229B  memlock 4096B  map_ids 21,22
  22: cgroup_skb  tag 2a142ef67aaad174  gpl
  	loaded_at 2019-01-19T09:09:45-0300  uid 0
  	xlated 296B  jited 229B  memlock 4096B  map_ids 21,22
  31: tracepoint  name sys_enter  tag 12504ba9402f952f  gpl
  	loaded_at 2019-01-19T09:19:56-0300  uid 0
  	xlated 512B  jited 374B  memlock 4096B  map_ids 30,29,28
  32: tracepoint  name sys_exit  tag c1bd85c092d6e4aa  gpl
  	loaded_at 2019-01-19T09:19:56-0300  uid 0
  	xlated 256B  jited 191B  memlock 4096B  map_ids 30,29
  # perf report -D | grep PERF_RECORD_BPF_EVENT | nl
     1	0 55834574849 0x4fc8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 13
     2	0 60129542145 0x5118 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 14
     3	0 64424509441 0x5268 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 15
     4	0 68719476737 0x53b8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 16
     5	0 73014444033 0x5508 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 17
     6	0 77309411329 0x5658 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 18
     7	0 90194313217 0x57a8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 21
     8	0 94489280513 0x58f8 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 22
     9	7 620922484360 0xb6390 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 29
    10	7 620922486018 0xb6410 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 2, flags 0, id 29
    11	7 620922579199 0xb6490 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 30
    12	7 620922580240 0xb6510 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 2, flags 0, id 30
    13	7 620922765207 0xb6598 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 31
    14	7 620922874543 0xb6620 [0x30]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 32
  #

There, the 31 and 32 tracepoint BPF programs put in place by 'perf trace'.

Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
Reviewed-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: kernel-team@fb.com
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20190117161521.1341602-7-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tools: Handle PERF_RECORD_KSYMBOL</title>
<updated>2019-01-21T20:00:57Z</updated>
<author>
<name>Song Liu</name>
<email>songliubraving@fb.com</email>
</author>
<published>2019-01-17T16:15:17Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=9aa0bfa370b278a539077002b3c660468d66b5e7'/>
<id>urn:sha1:9aa0bfa370b278a539077002b3c660468d66b5e7</id>
<content type='text'>
This patch handles PERF_RECORD_KSYMBOL in perf record/report.
Specifically, map and symbol are created for ksymbol register, and
removed for ksymbol unregister.

This patch also sets perf_event_attr.ksymbol properly. The flag is ON by
default.

Committer notes:

Use proper inttypes.h for u64, fixing the build in some environments
like in the android NDK r15c targetting ARM 32-bit.

I.e. fixing this build error:

  util/event.c: In function 'perf_event__fprintf_ksymbol':
  util/event.c:1489:10: error: format '%lx' expects argument of type 'long unsigned int', but argument 3 has type 'u64' [-Werror=format=]
            event-&gt;ksymbol_event.flags, event-&gt;ksymbol_event.name);
            ^
  cc1: all warnings being treated as errors

Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
Reviewed-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: kernel-team@fb.com
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20190117161521.1341602-6-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools lib traceevent, perf tools: Rename 'struct tep_event_format' to 'struct tep_event'</title>
<updated>2018-12-17T17:56:02Z</updated>
<author>
<name>Tzvetomir Stoyanov</name>
<email>tstoyanov@vmware.com</email>
</author>
<published>2018-11-30T15:44:07Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=97fbf3f0e0aa854ed33141dc9a5410f0ac6c71f3'/>
<id>urn:sha1:97fbf3f0e0aa854ed33141dc9a5410f0ac6c71f3</id>
<content type='text'>
In order to make libtraceevent into a proper library, variables, data
structures and functions require a unique prefix to prevent name space
conflicts.

This renames 'struct tep_event_format' to 'struct tep_event', which
describes more closely the purpose of the struct.

Signed-off-by: Tzvetomir Stoyanov &lt;tstoyanov@vmware.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: http://lkml.kernel.org/r/20181130154647.436403995@goodmis.org
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
[ Fixup conflict with 6e33c250a88f ("tools lib traceevent: Fix compile warnings in tools/lib/traceevent/event-parse.c") ]
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf trace: Introduce per-event maximum number of events property</title>
<updated>2018-10-22T17:27:12Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2018-10-22T17:14:16Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=a9c5e6c1e9bff42ca5f01ceb3092a27a010755fb'/>
<id>urn:sha1: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>
</entry>
<entry>
<title>perf evsel: Mark a evsel as disabled when asking the kernel do disable it</title>
<updated>2018-10-22T15:37:45Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2018-10-20T12:04:41Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=b7e8452b860c299f342a012922bdd9ab8f2bb722'/>
<id>urn:sha1:b7e8452b860c299f342a012922bdd9ab8f2bb722</id>
<content type='text'>
Because there may be more such events in the ring buffer that should be
discarded when an app decides to stop considering them.

At some point we'll do this with eBPF, this way we stop them at origin,
before they are placed in the ring buffer.

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-uzufuxws4hufigx07ue1dpv6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf evsel: Introduce per event max_events property</title>
<updated>2018-10-19T19:31:09Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2018-10-19T18:47:34Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=2fda5ada07f36f6cde39a52e7f05d86ea8ffdc33'/>
<id>urn:sha1:2fda5ada07f36f6cde39a52e7f05d86ea8ffdc33</id>
<content type='text'>
This simply adds the field to 'struct perf_evsel' and allows setting
it via the event parser, to test it lets trace trace:

First look at where in a function that receives an evsel we can put a probe
to read how evsel-&gt;max_events was setup:

  # perf probe -x ~/bin/perf -L trace__event_handler
  &lt;trace__event_handler@/home/acme/git/perf/tools/perf/builtin-trace.c:0&gt;
        0  static int trace__event_handler(struct trace *trace, struct perf_evsel *evsel,
                                          union perf_event *event __maybe_unused,
                                          struct perf_sample *sample)
        3  {
        4         struct thread *thread = machine__findnew_thread(trace-&gt;host, sample-&gt;pid, sample-&gt;tid);
        5         int callchain_ret = 0;

        7         if (sample-&gt;callchain) {
        8                 callchain_ret = trace__resolve_callchain(trace, evsel, sample, &amp;callchain_cursor);
        9                 if (callchain_ret == 0) {
       10                         if (callchain_cursor.nr &lt; trace-&gt;min_stack)
       11                                 goto out;
       12                         callchain_ret = 1;
                          }
                  }

See what variables we can probe at line 7:

  # perf probe -x ~/bin/perf -V trace__event_handler:7
  Available variables at trace__event_handler:7
          @&lt;trace__event_handler+89&gt;
                  int     callchain_ret
                  struct perf_evsel*      evsel
                  struct perf_sample*     sample
                  struct thread*  thread
                  struct trace*   trace
                  union perf_event*       event

Add a probe at that line asking for evsel-&gt;max_events to be collected and named
as "max_events":

  # perf probe -x ~/bin/perf trace__event_handler:7 'max_events=evsel-&gt;max_events'
  Added new event:
    probe_perf:trace__event_handler (on trace__event_handler:7 in /home/acme/bin/perf with max_events=evsel-&gt;max_events)

  You can now use it in all perf tools, such as:

  	perf record -e probe_perf:trace__event_handler -aR sleep 1

Now use 'perf trace', here aliased to just 'trace' and trace trace, i.e.
the first 'trace' is tracing just that 'probe_perf:trace__event_handler' event,
while the traced trace is tracing all scheduler tracepoints, will stop at two
events (--max-events 2) and will just set evsel-&gt;max_events for all the sched
tracepoints to 9, we will see the output of both traces intermixed:

  # trace -e *perf:*event_handler trace --max-events 2 -e sched:*/nr=9/
       0.000 :0/0 sched:sched_waking:comm=rcu_sched pid=10 prio=120 target_cpu=000
       0.009 :0/0 sched:sched_wakeup:comm=rcu_sched pid=10 prio=120 target_cpu=000
       0.000 trace/23949 probe_perf:trace__event_handler:(48c34a) max_events=0x9
       0.046 trace/23949 probe_perf:trace__event_handler:(48c34a) max_events=0x9
  #

Now, if the traced trace sends its output to /dev/null, we'll see just
what the first level trace outputs: that evsel-&gt;max_events is indeed
being set to 9:

  # trace -e *perf:*event_handler trace -o /dev/null --max-events 2 -e sched:*/nr=9/
       0.000 trace/23961 probe_perf:trace__event_handler:(48c34a) max_events=0x9
       0.030 trace/23961 probe_perf:trace__event_handler:(48c34a) max_events=0x9
  #

Now that we can set evsel-&gt;max_events, we can go to the next step, honour that
per-event property in 'perf trace'.

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: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: https://lkml.kernel.org/n/tip-og00yasj276joem6e14l1eas@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
</feed>
