linux-stable.git/tools/perf/Documentation, branch linux-5.17.y

perf record: Disable debuginfod by default

2022-01-15T20:41:25+00:00

Fedora 35 sets DEBUGINFOD_URLS by default, which might lead to
unexpected stalls in perf record exit path, when we try to cache
profiled binaries.

  # DEBUGINFOD_PROGRESS=1 ./perf record -a
  ^C[ perf record: Woken up 1 times to write data ]
  Downloading from https://debuginfod.fedoraproject.org/ 447069
  Downloading from https://debuginfod.fedoraproject.org/ 1502175
  Downloading \^Z

Disabling DEBUGINFOD_URLS by default in perf record and adding
debuginfod option and .perfconfig variable support to enable id.

  Default without debuginfo processing:
  # perf record -a

  Using system debuginfod setup:
  # perf record -a --debuginfod

  Using custom debuginfd url:
  # perf record -a --debuginfod='https://evenbetterdebuginfodserver.krava'

Adding single perf_debuginfod_setup function and using
it also in perf buildid-cache command.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Frank Ch. Eigler 
Cc: Ian Rogers 
Cc: Mark Rutland 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lore.kernel.org/lkml/20211209200425.303561-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf stat: Support --cputype option for hybrid events

2021-12-08T01:18:25+00:00

In previous patch, we have supported the syntax which enables
the event on a specified pmu, such as:

cpu_core//
cpu_atom//

While this syntax is not very easy for applying on a set of
events or applying on a group. In following example, we have to
explicitly assign the pmu prefix.

  # ./perf stat -e '{cpu_core/cycles/,cpu_core/instructions/}' -- sleep 1

   Performance counter stats for 'sleep 1':

           1,158,545      cpu_core/cycles/
           1,003,113      cpu_core/instructions/

         1.002428712 seconds time elapsed

A much easier way is:

  # ./perf stat --cputype core -e '{cycles,instructions}' -- sleep 1

   Performance counter stats for 'sleep 1':

           1,101,071      cpu_core/cycles/
             939,892      cpu_core/instructions/

         1.002363142 seconds time elapsed

For this example, the '--cputype' enables the events from specified
pmu (cpu_core).

If '--cputype' conflicts with pmu prefix, '--cputype' is ignored.

  # ./perf stat --cputype core -e cycles,cpu_atom/instructions/ -a -- sleep 1

   Performance counter stats for 'system wide':

          21,003,407      cpu_core/cycles/
             367,886      cpu_atom/instructions/

         1.002203520 seconds time elapsed

Signed-off-by: Jin Yao 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Jin Yao 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Peter Zijlstra 
Link: http://lore.kernel.org/lkml/20210909062215.10278-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Update link to AMD documentation

2021-12-08T01:18:24+00:00

This updates the link to documentation on AMD processors.  The new link
points to a page where users can find the Processor Programming
Reference (PPR) documents for the family and model codes corresponding
to processors they are using.

Signed-off-by: Sandipan Das 
Acked-by: Jiri Olsa 
Cc: Ananth Narayan 
Cc: Kajol Jain 
Cc: Kim Phillips 
Cc: Ravi Bangoria 
Cc: Robert Richter 
Cc: Santosh Shukla 
Link: https://lore.kernel.org/r/20211123084613.243792-2-sandipan.das@amd.com
Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Add info on AMD raw event encoding

2021-12-08T01:18:24+00:00

AMD processors have events with event select codes and unit masks larger
than a byte. The core PMU, for example, uses 12-bit event select codes
split between bits 0-7 and 32-35 of the PERF_CTL MSRs as can be seen
from /sys/bus/event_sources/devices/cpu/format/*.

The Processor Programming Reference (PPR) lists the event codes as
unified 12-bit hexadecimal values instead and the split between the bits
is not apparent to someone who is not aware of the layout of the
PERF_CTL MSRs.

8-bit event select codes continue to work as the layout matches that of
the PERF_CTL MSRs i.e. bits 0-7 for event select and 8-15 for unit mask.

This adds more details in the perf man pages about using
/sys/bus/event_sources/devices/*/format/* for determining the correct
raw event encoding scheme.

E.g. the "op_cache_hit_miss.op_cache_hit" event with code 0x28f and
umask 0x03 can be programmed using its symbolic name as:

  $ sudo perf --debug perf-event-open stat -e op_cache_hit_miss.op_cache_hit sleep 1
  ------------------------------------------------------------
  perf_event_attr:
    type                             4
    size                             128
    config                           0x20000038f
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
    disabled                         1
    inherit                          1
    enable_on_exec                   1
    exclude_guest                    1
  ------------------------------------------------------------
  [...]

One might use a simple eventsel+umask combination based on what the
current man pages say and incorrectly program the event as:

  $ sudo perf --debug perf-event-open stat -e r0328f sleep 1
  ------------------------------------------------------------
  perf_event_attr:
    type                             4
    size                             128
    config                           0x328f
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
    disabled                         1
    inherit                          1
    enable_on_exec                   1
    exclude_guest                    1
  ------------------------------------------------------------
  [...]

When it should have been based on the format from sysfs:

  $ cat /sys/bus/event_source/devices/cpu/format/event
  config:0-7,32-35

  $ sudo perf --debug perf-event-open stat -e r20000038f sleep 1
  ------------------------------------------------------------
  perf_event_attr:
    type                             4
    size                             128
    config                           0x20000038f
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
    disabled                         1
    inherit                          1
    enable_on_exec                   1
    exclude_guest                    1
  ------------------------------------------------------------
  [...]

Reviewed-by: Kajol Jain 
Signed-off-by: Sandipan Das 
Acked-by: Jiri Olsa 
Cc: Ananth Narayan 
Cc: Kim Phillips 
Cc: Ravi Bangoria 
Cc: Robert Richter 
Cc: Santosh Shukla 
Link: https://lore.kernel.org/r/20211123084613.243792-1-sandipan.das@amd.com
Signed-off-by: Arnaldo Carvalho de Melo

perf arm-spe: Update --switch-events docs in 'perf record'

2021-11-13T21:11:50+00:00

Update 'perf record' docs and ARM SPE recording options so that they are
consistent. This includes supporting the --no-switch-events flag in ARM
SPE as well.

Reviewed-by: Leo Yan 
Signed-off-by: German Gomez 
Acked-by: Namhyung Kim 
Cc: Alexander Shishkin 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Mark Rutland 
Cc: Mathieu Poirier 
Cc: Will Deacon 
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20211111133625.193568-3-german.gomez@arm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf inject: Add vmlinux and ignore-vmlinux arguments

2021-11-07T15:27:38+00:00

Other perf tools allow specifying the path to vmlinux. 'perf inject'
didn't have this argument which made some auxtrace workflows difficult.

Also add --ignore-vmlinux for consistency with other tools.

Suggested-by: Denis Nikitin 
Signed-off-by: James Clark 
Tested-by: Denis Nikitin 
Cc: Alexander Shishkin 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Link: https://lore.kernel.org/r/20211018134844.2627174-4-james.clark@arm.com
[ Added the perf-inject man page entries for these options, as noted by Denis ]
Signed-off-by: Arnaldo Carvalho de Melo

perf bpf: Pull in bpf_program__get_prog_info_linear()

2021-11-01T21:16:40+00:00

To prepare for impending deprecation of libbpf's bpf_program__get_prog_info_linear(),
pull in the function and associated helpers into the perf codebase and migrate
existing uses to the perf copy.

Since libbpf's deprecated definitions will still be visible to perf, it is necessary
to rename perf's definitions.

Signed-off-by: Dave Marchevsky 
Acked-by: Andrii Nakryiko 
Acked-by: Song Liu 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20211011082031.4148337-4-davemarchevsky@fb.com
Signed-off-by: Arnaldo Carvalho de Melo

perf script: Support instruction latency

2021-10-28T12:28:03+00:00

The instruction latency information can be recorded on
some platforms, e.g., the Intel Sapphire Rapids server. With both memory
latency (weight) and the new instruction latency information, users can
easily locate the expensive load instructions, and also understand the time
spent in different stages. The users can optimize their applications in
different pipeline stages.

Add a new field "ins_lat" to filter the instruction latency information,
which is available with sample type PERF_SAMPLE_WEIGHT_STRUCT.

Signed-off-by: Kan Liang 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Joe Mario 
Link: https://lore.kernel.org/r/1632929894-102778-2-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Support itrace d+o option to direct debug log to stdout

2021-10-27T19:21:01+00:00

It can be useful to see debug output in between normal output.

Add support for AUXTRACE_LOG_FLG_USE_STDOUT to Intel PT.

Reviewed-by: Andi Kleen 
Signed-off-by: Adrian Hunter 
Cc: Jiri Olsa 
Link: https://lore.kernel.org/r/20211027080334.365596-7-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf auxtrace: Add itrace d+o option to direct debug log to stdout

2021-10-27T19:20:45+00:00

It can be useful to see debug output in between normal output.

Add 'o' to the flags of debug option 'd', so that '--itrace=d+o' can
specify output of the debug log to stdout.

Reviewed-by: Andi Kleen 
Signed-off-by: Adrian Hunter 
Cc: Jiri Olsa 
Link: https://lore.kernel.org/r/20211027080334.365596-6-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo