linux.git/tools/perf/util/parse-events.c, branch v6.9

perf parse-events: Print all errors

2024-02-02T21:08:05+00:00

Prior to this patch the first and the last error encountered during
parsing are printed. To see other errors verbose needs
enabling. Unfortunately this can drop useful errors, in particular on
terms. This patch changes the errors so that instead of the first and
last all errors are recorded and printed, the underlying data
structure is changed to a list.

Before:
```
$ perf stat -e 'slots/edge=2/' true
event syntax error: 'slots/edge=2/'
                                \___ Bad event or PMU

Unable to find PMU or event on a PMU of 'slots'

Initial error:
event syntax error: 'slots/edge=2/'
                     \___ Cannot find PMU `slots'. Missing kernel support?
Run 'perf list' for a list of valid events

 Usage: perf stat [] []

    -e, --event    event selector. use 'perf list' to list available events
```

After:
```
$ perf stat -e 'slots/edge=2/' true
event syntax error: 'slots/edge=2/'
                     \___ Bad event or PMU

Unable to find PMU or event on a PMU of 'slots'

event syntax error: 'slots/edge=2/'
                                \___ value too big for format (edge), maximum is 1

event syntax error: 'slots/edge=2/'
                     \___ Cannot find PMU `slots'. Missing kernel support?
Run 'perf list' for a list of valid events

 Usage: perf stat [] []

    -e, --event    event selector. use 'perf list' to list available events
```

Signed-off-by: Ian Rogers 
Reviewed-by: James Clark 
Cc: Mark Rutland 
Cc: tchen168@asu.edu
Cc: Kan Liang 
Cc: Michael Petlan 
Signed-off-by: Namhyung Kim 
Link: https://lore.kernel.org/r/20240131134940.593788-3-irogers@google.com

perf parse-events: Make legacy events lower priority than sysfs/JSON

2023-11-27T13:21:27+00:00

The perf tool has previously made legacy events the priority so with
or without a PMU the legacy event would be opened:

  $ perf stat -e cpu-cycles,cpu/cpu-cycles/ true
  Using CPUID GenuineIntel-6-8D-1
  intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch
  Attempting to add event pmu 'cpu' with 'cpu-cycles,' that may result in non-fatal errors
  After aliases, add event pmu 'cpu' with 'cpu-cycles,' that may result in non-fatal errors
  Control descriptor is not initialized
  ------------------------------------------------------------
  perf_event_attr:
    type                             0 (PERF_TYPE_HARDWARE)
    size                             136
    config                           0 (PERF_COUNT_HW_CPU_CYCLES)
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
    disabled                         1
    inherit                          1
    enable_on_exec                   1
    exclude_guest                    1
  ------------------------------------------------------------
  sys_perf_event_open: pid 833967  cpu -1  group_fd -1  flags 0x8 = 3
  ------------------------------------------------------------
  perf_event_attr:
    type                             0 (PERF_TYPE_HARDWARE)
    size                             136
    config                           0 (PERF_COUNT_HW_CPU_CYCLES)
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
    disabled                         1
    inherit                          1
    enable_on_exec                   1
    exclude_guest                    1
  ------------------------------------------------------------
  ...

Fixes to make hybrid/BIG.little PMUs behave correctly, ie as core PMUs
capable of opening legacy events on each, removing hard coded "cpu_core"
and "cpu_atom" Intel PMU names, etc. caused a behavioral difference on
Apple/ARM due to latent issues in the PMU driver reported in:
https://lore.kernel.org/lkml/08f1f185-e259-4014-9ca4-6411d5c1bc65@marcan.st/

As part of that report Mark Rutland  requested
that legacy events not be higher in priority when a PMU is specified
reversing what has until this change been perf's default behavior. With
this change the above becomes:

  $ perf stat -e cpu-cycles,cpu/cpu-cycles/ true
  Using CPUID GenuineIntel-6-8D-1
  Attempt to add: cpu/cpu-cycles=0/
  ..after resolving event: cpu/event=0x3c/
  Control descriptor is not initialized
  ------------------------------------------------------------
  perf_event_attr:
    type                             0 (PERF_TYPE_HARDWARE)
    size                             136
    config                           0 (PERF_COUNT_HW_CPU_CYCLES)
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
    disabled                         1
    inherit                          1
    enable_on_exec                   1
    exclude_guest                    1
  ------------------------------------------------------------
  sys_perf_event_open: pid 827628  cpu -1  group_fd -1  flags 0x8 = 3
  ------------------------------------------------------------
  perf_event_attr:
    type                             4 (PERF_TYPE_RAW)
    size                             136
    config                           0x3c
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
    disabled                         1
    inherit                          1
    enable_on_exec                   1
    exclude_guest                    1
  ------------------------------------------------------------
  ...

So the second event has become a raw event as
/sys/devices/cpu/events/cpu-cycles exists.

A fix was necessary to config_term_pmu in parse-events.c as check_alias
expansion needs to happen after config_term_pmu, and config_term_pmu may
need calling a second time because of this.

config_term_pmu is updated to not use the legacy event when the PMU has
such a named event (either from JSON or sysfs).

The bulk of this change is updating all of the parse-events test
expectations so that if a sysfs/JSON event exists for a PMU the test
doesn't fail - a further sign, if it were needed, that the legacy event
priority was a known and tested behavior of the perf tool.

Reported-by: Hector Martin 
Signed-off-by: Ian Rogers 
Tested-by: Hector Martin 
Tested-by: Marc Zyngier 
Acked-by: Mark Rutland 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20231123042922.834425-1-irogers@google.com
[ Initialize the 'alias_rewrote_terms' variable to false to address a clang warning ]
Signed-off-by: Arnaldo Carvalho de Melo

perf pmu: Lazily compute default config

2023-10-17T19:40:50+00:00

The default config is computed during creation of the PMU and may do
things like scanning sysfs, when the PMU may just be used as part of
scanning. Change default_config to perf_event_attr_init_default, a
callback that is used when a default config needs initializing. This
avoids holding onto the memory for a perf_event_attr and copying.

On a tigerlake laptop running the pmu-scan benchmark:

Before:
Running 'internals/pmu-scan' benchmark:
Computing performance of sysfs PMU event scan for 100 times
  Average core PMU scanning took: 28.780 usec (+- 0.503 usec)
  Average PMU scanning took: 283.480 usec (+- 18.471 usec)
Number of openat syscalls: 30,227

After:
Running 'internals/pmu-scan' benchmark:
Computing performance of sysfs PMU event scan for 100 times
  Average core PMU scanning took: 27.880 usec (+- 0.169 usec)
  Average PMU scanning took: 245.260 usec (+- 15.758 usec)
Number of openat syscalls: 28,914

Over 3 runs it is a nearly 12% reduction in execution time and a 4.3%
of openat calls.

Signed-off-by: Ian Rogers 
Reviewed-by: Adrian Hunter 
Cc: Ravi Bangoria 
Cc: James Clark 
Cc: Suzuki K Poulose 
Cc: Yang Jihong 
Cc: Will Deacon 
Cc: Leo Yan 
Cc: Mike Leach 
Cc: Jing Zhang 
Cc: Kajol Jain 
Cc: Thomas Richter 
Cc: Kan Liang 
Cc: John Garry 
Cc: linux-arm-kernel@lists.infradead.org
Cc: coresight@lists.linaro.org
Link: https://lore.kernel.org/r/20231012175645.1849503-8-irogers@google.com
Signed-off-by: Namhyung Kim

perf parse-events: Fix unlikely memory leak when cloning terms

2023-10-12T17:01:57+00:00

Add missing free on an error path as detected by clang-tidy.

Signed-off-by: Ian Rogers 
Acked-by: Namhyung Kim 
Cc: Ravi Bangoria 
Cc: Nick Desaulniers 
Cc: Yang Jihong 
Cc: Huacai Chen 
Cc: Nathan Chancellor 
Cc: Kan Liang 
Cc: llvm@lists.linux.dev
Cc: Ming Wang 
Cc: Tom Rix 
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20231009183920.200859-16-irogers@google.com
Signed-off-by: Namhyung Kim

perf parse-events: Introduce 'struct parse_events_terms'

2023-09-11T13:26:36+00:00

parse_events_terms() existed in function names but was passed a
'struct list_head'.

As many parse_events functions take an evsel_config list as well as a
parse_event_term list, and the naming head_terms and head_config is
inconsistent, there's a potential to switch the lists and get errors.

Introduce a 'struct parse_events_terms', that just wraps a list_head, to
avoid this. Add the regular init/exit functions and transition the code
to use them.

Reviewed-by: James Clark 
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Rob Herring 
Link: https://lore.kernel.org/r/20230901233949.2930562-6-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Copy fewer term lists

2023-09-11T13:26:36+00:00

When trying to add events to multiple PMUs the term list is copied first
as adding the event will rewrite the event's name term into the sysfs
and/or json encoding terms (see perf_pmu__check_alias).

Change the parse events add API so the passed in term list is const,
then copy the list when modification is necessary.

Reviewed-by: James Clark 
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Rob Herring 
Link: https://lore.kernel.org/r/20230901233949.2930562-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Tidy up str parameter

2023-09-11T13:26:36+00:00

Add a const and rename str to event_name.

Reviewed-by: James Clark 
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Rob Herring 
Link: https://lore.kernel.org/r/20230901233949.2930562-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Remove unnecessary __maybe_unused

2023-09-11T13:26:36+00:00

The parameter head_terms is always used in get_config_terms.

Reviewed-by: James Clark 
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Rob Herring 
Link: https://lore.kernel.org/r/20230901233949.2930562-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Fixes relating to no_value terms

2023-09-02T11:12:15+00:00

A term may have no value in which case it is assumed to have a value
of 1. It doesn't just apply to alias/event terms so change the
parse_events_term__to_strbuf assert.

Commit 99e7138eb7897aa0 ("perf tools: Fail on using multiple bits long
terms without value") made it so that no_value terms could only be for a
single bit. Prior to commit 64199ae4b8a3 ("perf parse-events: Fix
propagation of term's no_value when cloning") this missed a test case
where config1 had no_value.

Fixes: 64199ae4b8a36038 ("perf parse-events: Fix propagation of term's no_value when cloning")
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Rob Herring 
Link: https://lore.kernel.org/r/20230901233949.2930562-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Fix propagation of term's no_value when cloning

2023-08-31T19:24:59+00:00

The no_value field in 'struct parse_events_term' indicates that the val
variable isn't used, the case for an event name.

Cloning wasn't propagating this, making cloned event name terms
appearing to have a constant assinged to them.

Working around the bug would check for a value of 1 assigned to value,
but then this meant a user value of 1 couldn't be differentiated causing
the value to be lost in debug printing and perf list.

The change fixes the cloning and updates the "val.num ==/!= 1" tests to
use no_value instead.

To better check the no_value is set appropriately parameter comments are
added for constant values.

This found that no_value wasn't set correctly in parse_events_multi_pmu_add,
which matters now that no_value is used to indicate an event name.

Fixes: 7a6e91644708d514 ("perf parse-events: Make common term list to strbuf helper")
Fixes: 99e7138eb7897aa0 ("perf tools: Fail on using multiple bits long terms without value")
Signed-off-by: Ian Rogers 
Tested-by: Kan Liang 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Rob Herring 
Link: https://lore.kernel.org/r/20230831071421.2201358-4-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo