linux-stable.git/tools/perf/Documentation, branch linux-5.8.y

perf stat: Turn off summary for interval mode by default

2020-09-09T17:14:22+00:00

[ Upstream commit ee6a961432e75393bd69bf70ba70bad90396fa82 ]

There's a risk that outputting interval mode summaries by default breaks
CSV consumers. It already broke pmu-tools/toplev.

So now we turn off the summary by default but we create a new option
'--summary' to enable the summary. This is active even when not using
CSV mode.

Before:

  root@kbl-ppc:~# perf stat -I1000 --interval-count 2
  #           time             counts unit events
       1.000265904           8,005.73 msec cpu-clock                 #    8.006 CPUs utilized
       1.000265904                601      context-switches          #    0.075 K/sec
       1.000265904                 10      cpu-migrations            #    0.001 K/sec
       1.000265904                  0      page-faults               #    0.000 K/sec
       1.000265904         66,746,521      cycles                    #    0.008 GHz
       1.000265904         71,874,398      instructions              #    1.08  insn per cycle
       1.000265904         13,356,781      branches                  #    1.668 M/sec
       1.000265904            298,756      branch-misses             #    2.24% of all branches
       2.001857667           8,012.52 msec cpu-clock                 #    8.013 CPUs utilized
       2.001857667                164      context-switches          #    0.020 K/sec
       2.001857667                 10      cpu-migrations            #    0.001 K/sec
       2.001857667                  2      page-faults               #    0.000 K/sec
       2.001857667          5,822,188      cycles                    #    0.001 GHz
       2.001857667          2,186,170      instructions              #    0.38  insn per cycle
       2.001857667            442,378      branches                  #    0.055 M/sec
       2.001857667             44,750      branch-misses             #   10.12% of all branches

   Performance counter stats for 'system wide':

           16,018.25 msec cpu-clock                 #    7.993 CPUs utilized
                 765      context-switches          #    0.048 K/sec
                  20      cpu-migrations            #    0.001 K/sec
                   2      page-faults               #    0.000 K/sec
          72,568,709      cycles                    #    0.005 GHz
          74,060,568      instructions              #    1.02  insn per cycle
          13,799,159      branches                  #    0.861 M/sec
             343,506      branch-misses             #    2.49% of all branches

         2.004118489 seconds time elapsed

After:

  root@kbl-ppc:~# perf stat -I1000 --interval-count 2
  #           time             counts unit events
       1.001336393           8,013.28 msec cpu-clock                 #    8.013 CPUs utilized
       1.001336393                 82      context-switches          #    0.010 K/sec
       1.001336393                  8      cpu-migrations            #    0.001 K/sec
       1.001336393                  0      page-faults               #    0.000 K/sec
       1.001336393          4,199,121      cycles                    #    0.001 GHz
       1.001336393          1,373,991      instructions              #    0.33  insn per cycle
       1.001336393            270,681      branches                  #    0.034 M/sec
       1.001336393             31,659      branch-misses             #   11.70% of all branches
       2.003905006           8,020.52 msec cpu-clock                 #    8.021 CPUs utilized
       2.003905006                184      context-switches          #    0.023 K/sec
       2.003905006                  8      cpu-migrations            #    0.001 K/sec
       2.003905006                  2      page-faults               #    0.000 K/sec
       2.003905006          5,446,190      cycles                    #    0.001 GHz
       2.003905006          2,312,547      instructions              #    0.42  insn per cycle
       2.003905006            451,691      branches                  #    0.056 M/sec
       2.003905006             37,925      branch-misses             #    8.40% of all branches

  root@kbl-ppc:~# perf stat -I1000 --interval-count 2 --summary
  #           time             counts unit events
       1.001313128           8,013.20 msec cpu-clock                 #    8.013 CPUs utilized
       1.001313128                 83      context-switches          #    0.010 K/sec
       1.001313128                  8      cpu-migrations            #    0.001 K/sec
       1.001313128                  0      page-faults               #    0.000 K/sec
       1.001313128          4,470,950      cycles                    #    0.001 GHz
       1.001313128          1,440,045      instructions              #    0.32  insn per cycle
       1.001313128            283,222      branches                  #    0.035 M/sec
       1.001313128             33,576      branch-misses             #   11.86% of all branches
       2.003857385           8,020.34 msec cpu-clock                 #    8.020 CPUs utilized
       2.003857385                154      context-switches          #    0.019 K/sec
       2.003857385                  8      cpu-migrations            #    0.001 K/sec
       2.003857385                  2      page-faults               #    0.000 K/sec
       2.003857385          4,515,676      cycles                    #    0.001 GHz
       2.003857385          2,180,449      instructions              #    0.48  insn per cycle
       2.003857385            435,254      branches                  #    0.054 M/sec
       2.003857385             31,179      branch-misses             #    7.16% of all branches

   Performance counter stats for 'system wide':

           16,033.53 msec cpu-clock                 #    7.992 CPUs utilized
                 237      context-switches          #    0.015 K/sec
                  16      cpu-migrations            #    0.001 K/sec
                   2      page-faults               #    0.000 K/sec
           8,986,626      cycles                    #    0.001 GHz
           3,620,494      instructions              #    0.40  insn per cycle
             718,476      branches                  #    0.045 M/sec
              64,755      branch-misses             #    9.01% of all branches

         2.006124542 seconds time elapsed

Fixes: c7e5b328a8d4 ("perf stat: Report summary for interval mode")
Signed-off-by: Jin Yao 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Peter Zijlstra 
Link: http://lore.kernel.org/lkml/20200903010113.32232-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf record/stat: Explicitly call out event modifiers in the documentation

2020-09-05T09:24:02+00:00

commit e48a73a312ebf19cc3d72aa74985db25c30757c1 upstream.

Event modifiers are not mentioned in the perf record or perf stat
manpages.  Add them to orient new users more effectively by pointing
them to the perf list manpage for details.

Fixes: 2055fdaf8703 ("perf list: Document precise event sampling for AMD IBS")
Signed-off-by: Kim Phillips 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Alexey Budankov 
Cc: Ian Rogers 
Cc: Jin Yao 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Paul Clarke 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Tony Jones 
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200901215853.276234-1-kim.phillips@amd.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf auxtrace: Add four itrace options

2020-06-01T15:24:23+00:00

This patch is to add four options to synthesize events which are
described as below:

 'f': synthesize first level cache events
 'm': synthesize last level cache events
 't': synthesize TLB events
 'a': synthesize remote access events

This four options will be used by ARM SPE as their first consumer.

Signed-off-by: Tan Xiaojun 
Tested-by: James Clark 
Acked-by: Adrian Hunter 
Cc: Al Grant 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Ian Rogers 
Cc: Jin Yao 
Cc: Jiri Olsa 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Mathieu Poirier 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lore.kernel.org/lkml/20200530122442.490-3-leo.yan@linaro.org
Signed-off-by: James Clark 
Signed-off-by: Leo Yan 
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add optional support for libpfm4

2020-05-29T19:51:38+00:00

This patch links perf with the libpfm4 library if it is available and
LIBPFM4 is passed to the build. The libpfm4 library contains hardware
event tables for all processors supported by perf_events. It is a helper
library that helps convert from a symbolic event name to the event
encoding required by the underlying kernel interface. This library is
open-source and available from: http://perfmon2.sf.net.

With this patch, it is possible to specify full hardware events by name.
Hardware filters are also supported. Events must be specified via the
--pfm-events and not -e option. Both options are active at the same time
and it is possible to mix and match:

  $ perf stat --pfm-events inst_retired:any_p:c=1:i -e cycles ....

One needs to explicitely ask for its inclusion by using the LIBPFM4 make
command line option, ie its opt-in rather than opt-out of feature
detection and build support.

Signed-off-by: Stephane Eranian 
Reviewed-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Alexei Starovoitov 
Cc: Alexey Budankov 
Cc: Andi Kleen 
Cc: Andrii Nakryiko 
Cc: Daniel Borkmann 
Cc: Florian Fainelli 
Cc: Greg Kroah-Hartman 
Cc: Igor Lubashev 
Cc: Jin Yao 
Cc: Jiri Olsa 
Cc: Jiwei Sun 
Cc: John Garry 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Martin KaFai Lau 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Yonghong Song 
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: yuzhoujian 
Link: http://lore.kernel.org/lkml/20200505182943.218248-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf record: Respect --no-switch-events

2020-05-28T14:33:36+00:00

Context switch events are added automatically by Intel PT and Coresight.

Make it possible to suppress them. That is useful for tracing the
scheduler without the disturbance that the switch event processing
creates.

Example:

  Prerequisites:

    $ which perf
    ~/bin/perf
    $ sudo setcap "cap_sys_rawio,cap_sys_admin,cap_sys_ptrace,cap_syslog,cap_ipc_lock=ep" ~/bin/perf
    $ sudo chmod +r /proc/kcore

  Before:

    $ perf record --no-switch-events --kcore -a -e intel_pt//k -- sleep 0.001
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.938 MB perf.data ]
    $ perf script -D | grep PERF_RECORD_SWITCH | wc -l
    572

  After:

    $ perf record --no-switch-events --kcore -a -e intel_pt//k -- sleep 0.001
    Warning:
    Intel Processor Trace decoding will not be possible except for kernel tracing!
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.838 MB perf.data ]
    $ perf script -D | grep PERF_RECORD_SWITCH | wc -l
    0

    $ sudo chmod go-r /proc/kcore
    $ sudo setcap -r ~/bin/perf

Signed-off-by: Adrian Hunter 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Mathieu Poirier 
Link: http://lore.kernel.org/lkml/20200528120859.21604-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf metricgroup: Add options to not group or merge

2020-05-28T13:03:28+00:00

Add --metric-no-group that causes all events within metrics to not be
grouped. This can allow the event to get more time when multiplexed, but
may also lower accuracy.
Add --metric-no-merge option. By default events in different metrics may
be shared if the group of events for one metric is the same or larger
than that of the second. Sharing may increase or lower accuracy and so
is now configurable.

Signed-off-by: Ian Rogers 
Acked-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Andrii Nakryiko 
Cc: Cong Wang 
Cc: Jin Yao 
Cc: John Garry 
Cc: Kajol Jain 
Cc: Kan Liang 
Cc: Kim Phillips 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Paul Clarke 
Cc: Peter Zijlstra 
Cc: Song Liu 
Cc: Srikar Dronamraju 
Cc: Stephane Eranian 
Cc: Vince Weaver 
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200520182011.32236-7-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf config: Add stat.big-num support

2020-05-28T13:03:27+00:00

Add support for new "stat.big-num" boolean option.

This allows a user to set a default for "--no-big-num" for "perf stat"
commands.

--
  $ perf config stat.big-num
  $ perf stat --event cycles /bin/true

   Performance counter stats for '/bin/true':

             778,849      cycles
  [...]
  $ perf config stat.big-num=false
  $ perf config stat.big-num
  stat.big-num=false
  $ perf stat --event cycles /bin/true

   Performance counter stats for '/bin/true':

              769622      cycles
  [...]
--

There is an interaction with "--field-separator" that must be
accommodated, such that specifying "--big-num --field-separator={x}"
still reports an invalid combination of options.

Documentation for perf-config and perf-stat updated.

Signed-off-by: Paul Clarke 
Tested-by: Arnaldo Carvalho de Melo 
Link: http://lore.kernel.org/lkml/1589991815-17951-1-git-send-email-pc@us.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Introduce security.txt file to document related issues

2020-05-28T13:03:26+00:00

Publish instructions on how to apply LSM hooks for access control to
perf_event_open() syscall on Fedora distro with Targeted SELinux policy
and then manage access to the syscall.

Signed-off-by: Alexey Budankov 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: linux-security-module@vger.kernel.org
Cc: selinux@vger.kernel.org
Link: http://lore.kernel.org/lkml/290ded0a-c422-3749-5180-918fed1ee30f@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Extend CAP_SYS_ADMIN with CAP_PERFMON where needed

2020-05-28T13:03:26+00:00

Extend CAP_SYS_ADMIN with CAP_PERFMON in the docs.

Signed-off-by: Alexey Budankov 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: linux-security-module@vger.kernel.org
Cc: selinux@vger.kernel.org
Link: http://lore.kernel.org/lkml/3b19cf79-f02d-04b4-b8b1-0039ac023b2c@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf c2c: Fix 'perf c2c record -e list' to show the default events used

2020-05-28T13:03:25+00:00

When the event is passed as list, the default events should be listed as
per 'perf mem record -e list'. Previous behavior is:

  $ perf c2c record -e list
  failed: event 'list' not found, use '-e list' to get list of available events

   Usage: perf c2c record [] []
      or: perf c2c record [] --  []

      -e, --event    event selector. Use 'perf mem record -e list' to list available events
  $

New behavior:

  $ perf c2c record -e list
  ldlat-loads  : available
  ldlat-stores : available

v3: is a rebase.
v2: addresses review comments by Jiri Olsa.

https://lore.kernel.org/lkml/20191127081844.GH32367@krava/
Signed-off-by: Ian Rogers 
Tested-by: Arnaldo Carvalho de Melo 
Acked-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lore.kernel.org/lkml/20200507220604.3391-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo