linux-stable.git/tools/perf/Documentation, branch v5.8

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

perf intel-pt: Update documentation about using /proc/kcore

2020-05-05T19:35:30+00:00

Update documentation to reflect the advent of the --kcore option for
'perf record'.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Link: http://lore.kernel.org/lkml/20200429150751.12570-10-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Update documentation about itrace G and L options

2020-05-05T19:35:30+00:00

Provide a little more information about the new G and L options,
particularly the issue with large PEBs.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Link: http://lore.kernel.org/lkml/20200429150751.12570-9-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo