linux.git/tools/perf/util/config.c, branch for-next

perf scripting python: Add function to get a config value

2024-09-24T18:47:03+00:00

This can be used to get config values like which objdump Perf uses for
disassembly.

Reviewed-by: Leo Yan 
Signed-off-by: James Clark 
Tested-by: Ganapatrao Kulkarni 
Cc: Ben Gainey 
Cc: Suzuki K Poulose 
Cc: Will Deacon 
Cc: Mathieu Poirier 
Cc: Mike Leach 
Cc: Ruidong Tian 
Cc: Leo Yan 
Cc: Benjamin Gray 
Cc: linux-arm-kernel@lists.infradead.org
Cc: coresight@lists.linaro.org
Cc: John Garry 
Cc: scclevenger@os.amperecomputing.com
Link: https://lore.kernel.org/r/20240916135743.1490403-4-james.clark@linaro.org
Signed-off-by: Namhyung Kim

perf parse-events: Remove BPF event support

2023-08-15T19:41:48+00:00

New features like the BPF --filter support in perf record have made the
BPF event functionality somewhat redundant. As shown by commit
fcb027c1a4f6 ("perf tools: Revert enable indices setting syntax for BPF
map") and commit 14e4b9f4289a ("perf trace: Raw augmented syscalls fix
libbpf 1.0+ compatibility") the BPF event support hasn't been well
maintained and it adds considerable complexity in areas like event
parsing, not least as '/' is a separator for event modifiers as well as
in paths.

This patch removes support in the event parser for BPF events and then
the associated functions are removed. This leads to the removal of whole
source files like bpf-loader.c.  Removing support means that augmented
syscalls in perf trace is broken, this will be fixed in a later commit
adding support using BPF skeletons.

The removal of BPF events causes an unused label warning from flex
generated code, so update build to ignore it:

  ```
  util/parse-events-flex.c:2704:1: error: label ‘find_rule’ defined but not used [-Werror=unused-label]
  2704 | find_rule: /* we branch to this label when backing up */
  ```

Committer notes:

Extracted from a larger patch that was also removing the support for
linking with libllvm and libclang, that were an alternative to using an
external clang execution to compile the .c event source code into BPF
bytecode.

Testing it:

  # perf trace -e /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c
  event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c'
                        \___ Bad event or PMU

  Unabled to find PMU or event on a PMU of 'home'

  Initial error:
  event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c'
                        \___ Cannot find PMU `home'. Missing kernel support?
  Run 'perf list' for a list of valid events

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

      -e, --event    event/syscall selector. use 'perf list' to list available events
  #

Signed-off-by: Ian Rogers 
Acked-by: Jiri Olsa 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Andrii Nakryiko 
Cc: Anshuman Khandual 
Cc: Athira Rajeev 
Cc: Brendan Gregg 
Cc: Carsten Haitzler 
Cc: Eduard Zingerman 
Cc: Fangrui Song 
Cc: He Kuang 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Madhavan Srinivasan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Nathan Chancellor 
Cc: Naveen N. Rao 
Cc: Nick Desaulniers 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Rob Herring 
Cc: Tiezhu Yang 
Cc: Tom Rix 
Cc: Wang Nan 
Cc: Wang ShaoBo 
Cc: Yang Jihong 
Cc: Yonghong Song 
Cc: YueHaibing 
Cc: bpf@vger.kernel.org
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/r/20230810184853.2860737-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo 

Signed-off-by: Arnaldo Carvalho de Melo

perf srcline: Add a timeout to reading from addr2line

2023-06-14T21:19:06+00:00

addr2line may fail to send expected values causing perf to wait
indefinitely. Add a 1 second timeout (twice the timeout for reading from
/proc/pid/maps) so that such reads don't cause perf to appear to lock
up.

There are already checks that the file for addr2line contains a debug
section but this isn't always sufficient. The problem was observed when
a valid elf file would set the configuration for binutils addr2line,
then a later read of vmlinux with ELF debug sections would cause a
failing write/read which would block indefinitely.

As a service to future readers, if the io hits eof or an error, cleanup
the addr2line process.

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Yang Jihong 
Link: https://lore.kernel.org/r/20230608061812.3715566-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf path: Make mkpath thread safe, remove 16384 bytes from .bss

2023-05-28T13:24:14+00:00

Avoid 4 static arrays for paths, pass in a char[] buffer to use. Makes
mkpath thread safe for the small number of users. Also removes 16,384
bytes from .bss.

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: K Prateek Nayak 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Paolo Bonzini 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Ross Zwisler 
Cc: Sean Christopherson 
Cc: Steven Rostedt (VMware) 
Cc: Tiezhu Yang 
Cc: Yang Jihong 
Link: https://lore.kernel.org/r/20230526183401.2326121-13-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf config: Add missing newline on pr_warning() call in home_perfconfig()

2022-10-27T19:37:26+00:00

Add missing newline on pr_warning() call in home_perfconfig().

Before:
  # perf record
  File /home/yangjihong/.perfconfig not owned by current user or root, ignoring it.Couldn't synthesize bpf events.

After:
  # perf record
  File /home/yangjihong/.perfconfig not owned by current user or root, ignoring it.
  Couldn't synthesize bpf events.

Signed-off-by: Yang Jihong 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20221022092735.114967-4-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add perf_config_scan()

2022-10-04T11:55:21+00:00

To simplify getting a single config value, add a function to scan a config
variable.

Reviewed-by: Andi Kleen 
Reviewed-by: Namhyung Kim 
Signed-off-by: Adrian Hunter 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Link: https://lore.kernel.org/r/20220905073424.3971-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf config: Refine error message to eliminate confusion

2021-09-27T12:32:28+00:00

If there is no configuration file at first, the user can write any pair
of "key.subkey=value" to the newly created configuration file, while
value validation against a valid configurable key is *deferred* until
the next execution or the implied execution of "perf config ... ".

For example:

  $ rm ~/.perfconfig
  $ perf config call-graph.dump-size=65529
  $ cat ~/.perfconfig
  # this file is auto-generated.
  [call-graph]
 	dump-size = 65529
  $ perf config call-graph.dump-size=2048
  callchain: Incorrect stack dump size (max 65528): 65529
  Error: wrong config key-value pair call-graph.dump-size=65529

The user might expect that the second value 2048 is valid and can be
updated to the configuration file, but the error message is very
confusing because the first value 65529 is not reported as an error
during the last configuration.

It is recommended not to change the current behavior of delayed
validation (as more effort is needed), but to refine the original error
message to *clearly indicate* that the cause of the error is the
configuration file.

Signed-off-by: Like Xu 
Acked-by: Ian Rogers 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lore.kernel.org/lkml/20210924115817.58689-1-likexu@tencent.com
Signed-off-by: Arnaldo Carvalho de Melo

perf config: Fix caching and memory leak in perf_home_perfconfig()

2021-08-30T13:06:22+00:00

Acaict, perf_home_perfconfig() is supposed to cache the result of
home_perfconfig, which returns the default location of perfconfig for
the user, given the HOME environment variable.

However, the current implementation calls home_perfconfig every time
perf_home_perfconfig() is called (so no caching is actually performed),
replacing the previous pointer, thus also causing a memory leak.

This patch adds a check of whether either config or failed is set and,
in that case, directly returns config without calling home_perfconfig at
each invocation.

Fixes: f5f03e19ce14fc31 ("perf config: Add perf_home_perfconfig function")
Signed-off-by: Riccardo Mancini 
Cc: Alexander Shishkin 
Cc: Ian Rogers 
Cc: Jin Yao 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Song Liu 
Link: http://lore.kernel.org/lkml/20210820130817.740536-1-rickyman7@gmail.com
[ Removed needless double check for the 'failed' variable ]
Signed-off-by: Arnaldo Carvalho de Melo

perf stat: Introduce config stat.bpf-counter-events

2021-04-29T13:30:58+00:00

Currently, to use BPF to aggregate perf event counters, the user uses
--bpf-counters option. Enable "use bpf by default" events with a config
option, stat.bpf-counter-events. Events with name in the option will use
BPF.

This also enables mixed BPF event and regular event in the same sesssion.
For example:

   perf config stat.bpf-counter-events=instructions
   perf stat -e instructions,cs

The second command will use BPF for "instructions" but not "cs".

Signed-off-by: Song Liu 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Song Liu 
Link: https://lore.kernel.org/r/20210425214333.1090950-4-song@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf stat: Align CSV output for summary mode

2021-03-24T13:21:49+00:00

The 'perf stat' subcommand supports the request for a summary of the
interval counter readings.  But the summary lines break the CSV output
so it's hard for scripts to parse the result.

Before:

  # perf stat -x, -I1000 --interval-count 1 --summary
       1.001323097,8013.48,msec,cpu-clock,8013483384,100.00,8.013,CPUs utilized
       1.001323097,270,,context-switches,8013513297,100.00,0.034,K/sec
       1.001323097,13,,cpu-migrations,8013530032,100.00,0.002,K/sec
       1.001323097,184,,page-faults,8013546992,100.00,0.023,K/sec
       1.001323097,20574191,,cycles,8013551506,100.00,0.003,GHz
       1.001323097,10562267,,instructions,8013564958,100.00,0.51,insn per cycle
       1.001323097,2019244,,branches,8013575673,100.00,0.252,M/sec
       1.001323097,106152,,branch-misses,8013585776,100.00,5.26,of all branches
  8013.48,msec,cpu-clock,8013483384,100.00,7.984,CPUs utilized
  270,,context-switches,8013513297,100.00,0.034,K/sec
  13,,cpu-migrations,8013530032,100.00,0.002,K/sec
  184,,page-faults,8013546992,100.00,0.023,K/sec
  20574191,,cycles,8013551506,100.00,0.003,GHz
  10562267,,instructions,8013564958,100.00,0.51,insn per cycle
  2019244,,branches,8013575673,100.00,0.252,M/sec
  106152,,branch-misses,8013585776,100.00,5.26,of all branches

The summary line loses the timestamp column, which breaks the CSV
output.

We add a column at the original 'timestamp' position and it just says
'summary' for the summary line.

After:

  # perf stat -x, -I1000 --interval-count 1 --summary
       1.001196053,8012.72,msec,cpu-clock,8012722903,100.00,8.013,CPUs utilized
       1.001196053,218,,context-switches,8012753271,100.00,0.027,K/sec
       1.001196053,9,,cpu-migrations,8012769767,100.00,0.001,K/sec
       1.001196053,0,,page-faults,8012786257,100.00,0.000,K/sec
       1.001196053,15004518,,cycles,8012790637,100.00,0.002,GHz
       1.001196053,7954691,,instructions,8012804027,100.00,0.53,insn per cycle
       1.001196053,1590259,,branches,8012814766,100.00,0.198,M/sec
       1.001196053,82601,,branch-misses,8012824365,100.00,5.19,of all branches
           summary,8012.72,msec,cpu-clock,8012722903,100.00,7.986,CPUs utilized
           summary,218,,context-switches,8012753271,100.00,0.027,K/sec
           summary,9,,cpu-migrations,8012769767,100.00,0.001,K/sec
           summary,0,,page-faults,8012786257,100.00,0.000,K/sec
           summary,15004518,,cycles,8012790637,100.00,0.002,GHz
           summary,7954691,,instructions,8012804027,100.00,0.53,insn per cycle
           summary,1590259,,branches,8012814766,100.00,0.198,M/sec
           summary,82601,,branch-misses,8012824365,100.00,5.19,of all branches

Now it's easy for script to analyse the summary lines.

Of course, we also consider not to break possible existing scripts which
can continue to use the broken CSV format by using a new '--no-csv-summary.'
option.

  # perf stat -x, -I1000 --interval-count 1 --summary --no-csv-summary
       1.001213261,8012.67,msec,cpu-clock,8012672327,100.00,8.013,CPUs utilized
       1.001213261,197,,context-switches,8012703742,100.00,24.586,/sec
       1.001213261,9,,cpu-migrations,8012720902,100.00,1.123,/sec
       1.001213261,644,,page-faults,8012738266,100.00,80.373,/sec
       1.001213261,18350698,,cycles,8012744109,100.00,0.002,GHz
       1.001213261,12745021,,instructions,8012759001,100.00,0.69,insn per cycle
       1.001213261,2458033,,branches,8012770864,100.00,306.768,K/sec
       1.001213261,102107,,branch-misses,8012781751,100.00,4.15,of all branches
  8012.67,msec,cpu-clock,8012672327,100.00,7.985,CPUs utilized
  197,,context-switches,8012703742,100.00,24.586,/sec
  9,,cpu-migrations,8012720902,100.00,1.123,/sec
  644,,page-faults,8012738266,100.00,80.373,/sec
  18350698,,cycles,8012744109,100.00,0.002,GHz
  12745021,,instructions,8012759001,100.00,0.69,insn per cycle
  2458033,,branches,8012770864,100.00,306.768,K/sec
  102107,,branch-misses,8012781751,100.00,4.15,of all branches

This option can be enabled in perf config by setting the variable
'stat.no-csv-summary'.

  # perf config stat.no-csv-summary=true

  # perf config -l
  stat.no-csv-summary=true

  # perf stat -x, -I1000 --interval-count 1 --summary
       1.001330198,8013.28,msec,cpu-clock,8013279201,100.00,8.013,CPUs utilized
       1.001330198,205,,context-switches,8013308394,100.00,25.583,/sec
       1.001330198,10,,cpu-migrations,8013324681,100.00,1.248,/sec
       1.001330198,0,,page-faults,8013340926,100.00,0.000,/sec
       1.001330198,8027742,,cycles,8013344503,100.00,0.001,GHz
       1.001330198,2871717,,instructions,8013356501,100.00,0.36,insn per cycle
       1.001330198,553564,,branches,8013366204,100.00,69.081,K/sec
       1.001330198,54021,,branch-misses,8013375952,100.00,9.76,of all branches
  8013.28,msec,cpu-clock,8013279201,100.00,7.985,CPUs utilized
  205,,context-switches,8013308394,100.00,25.583,/sec
  10,,cpu-migrations,8013324681,100.00,1.248,/sec
  0,,page-faults,8013340926,100.00,0.000,/sec
  8027742,,cycles,8013344503,100.00,0.001,GHz
  2871717,,instructions,8013356501,100.00,0.36,insn per cycle
  553564,,branches,8013366204,100.00,69.081,K/sec
  54021,,branch-misses,8013375952,100.00,9.76,of all branches

Signed-off-by: Jin Yao 
Acked-by: Andi Kleen 
Acked-by: Jiri Olsa 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Alexander Shishkin 
Cc: Jin Yao 
Cc: Kan Liang 
Cc: Peter Zijlstra 
Link: http://lore.kernel.org/lkml/20210319070156.20394-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo