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Namhyung Kim 86a12b92a9 perf ftrace: Display latency statistics at the end
Sometimes users also want to see average latency as well as histogram.

Display latency statistics like avg, max, min at the end.

  $ sudo ./perf ftrace latency -ab -T synchronize_rcu -- ...
  #   DURATION     |      COUNT | GRAPH                                          |
       0 - 1    us |          0 |                                                |
       1 - 2    us |          0 |                                                |
       2 - 4    us |          0 |                                                |
       4 - 8    us |          0 |                                                |
       8 - 16   us |          0 |                                                |
      16 - 32   us |          0 |                                                |
      32 - 64   us |          0 |                                                |
      64 - 128  us |          0 |                                                |
     128 - 256  us |          0 |                                                |
     256 - 512  us |          0 |                                                |
     512 - 1024 us |          0 |                                                |
       1 - 2    ms |          0 |                                                |
       2 - 4    ms |          0 |                                                |
       4 - 8    ms |          0 |                                                |
       8 - 16   ms |          1 | #####                                          |
      16 - 32   ms |          7 | ########################################       |
      32 - 64   ms |          0 |                                                |
      64 - 128  ms |          0 |                                                |
     128 - 256  ms |          0 |                                                |
     256 - 512  ms |          0 |                                                |
     512 - 1024 ms |          0 |                                                |
       1 - ...   s |          0 |                                                |

  # statistics  (in usec)
    total time:               171832
      avg time:                21479
      max time:                30906
      min time:                15869
         count:                    8

Committer testing:

  root@number:~# perf ftrace latency -nab --bucket-range 100 --max-latency 512 -T switch_mm_irqs_off sleep 1
  #   DURATION     |      COUNT | GRAPH                                          |
       0 -  100 ns |        314 | ##                                             |
     100 -  200 ns |       1843 | #############                                  |
     200 -  300 ns |       1390 | ##########                                     |
     300 -  400 ns |        844 | ######                                         |
     400 -  500 ns |        480 | ###                                            |
     500 -  512 ns |        315 | ##                                             |
     512 -  ... ns |         16 |                                                |

  # statistics  (in nsec)
    total time:              2448936
      avg time:                  387
      max time:                 3285
      min time:                   82
         count:                 6328
  root@number:~#

Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250107224352.1128669-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2025-01-08 17:20:42 -03:00
arch OpenRISC fixes for 6.13-rc3 2024-12-12 13:20:53 -08:00
block blk-mq: move cpuhp callback registering out of q->sysfs_lock 2024-12-06 09:48:46 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto module: Convert symbol namespace to string literal 2024-12-02 11:34:44 -08:00
Documentation perf Documentation: Clarify sysfs event names characters 2025-01-08 17:20:42 -03:00
drivers Including fixes from bluetooth, netfilter and wireless. 2024-12-12 11:28:05 -08:00
fs three kernel server fixes 2024-12-12 17:33:20 -08:00
include Including fixes from bluetooth, netfilter and wireless. 2024-12-12 11:28:05 -08:00
init - The series "resource: A couple of cleanups" from Andy Shevchenko 2024-11-25 16:09:48 -08:00
io_uring io_uring: Change res2 parameter type in io_uring_cmd_done 2024-12-03 06:33:13 -07:00
ipc - The series "resource: A couple of cleanups" from Andy Shevchenko 2024-11-25 16:09:48 -08:00
kernel Probes fixes for v6.13-rc1: 2024-12-10 18:15:25 -08:00
lib - Remove if_not_guard() as it is generating incorrect code 2024-12-09 10:34:41 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm 24 hotfixes. 17 are cc:stable. 15 are MM and 9 are non-MM. 2024-12-08 11:26:13 -08:00
net Including fixes from bluetooth, netfilter and wireless. 2024-12-12 11:28:05 -08:00
rust block-6.13-20242901 2024-11-30 15:47:29 -08:00
samples BPF fixes: 2024-12-06 15:07:48 -08:00
scripts openrisc: place exception table at the head of vmlinux 2024-12-10 12:04:19 +00:00
security Including fixes from can and netfilter. 2024-12-05 10:25:06 -08:00
sound sound fixes for 6.13-rc2 2024-12-06 11:46:39 -08:00
tools perf ftrace: Display latency statistics at the end 2025-01-08 17:20:42 -03:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt VFIO updates for v6.13 2024-11-27 12:57:03 -08:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: enable Clippy's check-private-items 2024-10-07 21:39:57 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Kbuild updates for v6.13 2024-11-30 13:41:50 -08:00
.mailmap media updates for v6.13-rc1 2024-11-20 14:01:15 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS cgroup: Changes for v6.13 2024-11-20 09:54:49 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Including fixes from bluetooth, netfilter and wireless. 2024-12-12 11:28:05 -08:00
Makefile Linux 6.13-rc2 2024-12-08 14:03:39 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.