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Yang Jihong f98919ec4f perf kwork: Implement 'report' subcommand
Implements framework of 'perf kwork report', which is used to report
time properties such as run time and frequency:

Test cases:

  # perf kwork

   Usage: perf kwork [<options>] {record|report}

      -D, --dump-raw-trace  dump raw trace in ASCII
      -f, --force           don't complain, do it
      -k, --kwork <kwork>   list of kwork to profile (irq, softirq, workqueue, etc)
      -v, --verbose         be more verbose (show symbol address, etc)

  # perf kwork report -h

   Usage: perf kwork report [<options>]

      -C, --cpu <cpu>       list of cpus to profile
      -i, --input <file>    input file name
      -n, --name <name>     event name to profile
      -s, --sort <key[,key2...]>
                            sort by key(s): runtime, max, count
      -S, --with-summary    Show summary with statistics
          --time <str>      Time span for analysis (start,stop)

  # perf kwork report

    Kwork Name                     | Cpu  | Total Runtime | Count     | Max runtime   | Max runtime start   | Max runtime end     |
   --------------------------------------------------------------------------------------------------------------------------------
   --------------------------------------------------------------------------------------------------------------------------------

  # perf kwork report -S

    Kwork Name                     | Cpu  | Total Runtime | Count     | Max runtime   | Max runtime start   | Max runtime end     |
   --------------------------------------------------------------------------------------------------------------------------------
   --------------------------------------------------------------------------------------------------------------------------------
    Total count            :         0
    Total runtime   (msec) :     0.000 (0.000% load average)
    Total time span (msec) :     0.000
   --------------------------------------------------------------------------------------------------------------------------------

  # perf kwork report -C 0,100
  Requested CPU 100 too large. Consider raising MAX_NR_CPUS
  Invalid cpu bitmap

  # perf kwork report -s runtime1
    Error: Unknown --sort key: `runtime1'

   Usage: perf kwork report [<options>]

      -C, --cpu <cpu>       list of cpus to profile
      -i, --input <file>    input file name
      -n, --name <name>     event name to profile
      -s, --sort <key[,key2...]>
                            sort by key(s): runtime, max, count
      -S, --with-summary    Show summary with statistics
          --time <str>      Time span for analysis (start,stop)

  # perf kwork report -i perf_no_exist.data
  failed to open perf_no_exist.data: No such file or directory

  # perf kwork report --time 00FFF,
  Invalid time span

Since there are no report supported events, the output is empty.

Briefly describe the data structure:

1. "class" indicates event type. For example, irq and softiq correspond
to different types.

2. "cluster" refers to a specific event corresponding to a type. For
example, RCU and TIMER in softirq correspond to different clusters,
which contains three types of events: raise, entry, and exit.

3. "atom" includes time of each sample and sample of the previous phase.
(For example, exit corresponds to entry, which is used for timehist.)

Committer notes:

- Add {} for multiline if blocks.

- report_print_work() should either return that ret variable that
  accounts how many bytes were printed or stop accounting and be void.
  Do the former for now to avoid this:

builtin-kwork.c:534:6: error: variable 'ret' set but not used [-Werror,-Wunused-but-set-variable]
        int ret = 0;
            ^
1 error generated.

  When building with:

  ⬢[acme@toolbox perf]$ clang --version
  clang version 13.0.0 (https://github.com/llvm/llvm-project e8991caea8690ec2d17b0b7e1c29bf0da6609076)

Also:

  -       if ((dst_type >= 0) && (dst_type < KWORK_TRACE_MAX)) {
  +       if (dst_type < KWORK_TRACE_MAX) {

Several versions of clang and at least this gcc:

   3    51.40 alpine:3.9                    : FAIL gcc version 8.3.0 (Alpine 8.3.0)
    builtin-kwork.c:411:16: error: comparison of unsigned enum expression >= 0 is
          always true [-Werror,-Wtautological-compare]
            if ((dst_type >= 0) && (dst_type < KWORK_TRACE_MAX)) {

As the first entry in a enum is zero.

Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220709015033.38326-7-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-07-26 16:30:05 -03:00
arch - Improve the check whether the kernel supports WP mappings so that it 2022-07-17 08:27:30 -07:00
block block: fix missing blkcg_bio_issue_init 2022-07-14 10:54:49 -06:00
certs Certs changes 2022-06-21 12:13:53 -05:00
crypto crypto: s390 - do not depend on CRYPTO_HW for SIMD implementations 2022-07-06 20:04:06 -07:00
Documentation RISC-V: 2022-07-15 10:31:46 -07:00
drivers Second v5.19 rc pull request 2022-07-18 17:16:22 -07:00
fs for-5.19-rc7-tag 2022-07-16 13:48:55 -07:00
include Input updates for v5.19-rc6 2022-07-17 07:52:46 -07:00
init gcc-12: disable '-Warray-bounds' universally for now 2022-06-09 10:11:12 -07:00
ipc ipc: Free mq_sysctls if ipc namespace creation failed 2022-06-22 17:47:41 -05:00
kernel watchqueue: make sure to serialize 'wqueue->defunct' properly 2022-07-20 10:46:07 -07:00
lib ubsan: disable UBSAN_DIV_ZERO for clang 2022-07-14 15:45:26 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: split huge PUD on wp_huge_pud fallback 2022-07-03 15:42:33 -07:00
net net/tls: Check for errors in tls_device_init 2022-07-14 10:12:39 -07:00
samples Fixes and minor clean ups for tracing: 2022-07-12 16:17:40 -07:00
scripts Just when you thought that all the speculation bugs were addressed and 2022-07-11 18:15:25 -07:00
security lockdown: Fix kexec lockdown bypass with ima policy 2022-07-20 09:56:48 -07:00
sound ALSA: hda/realtek - Enable the headset-mic on a Xiaomi's laptop 2022-07-13 12:42:41 +02:00
tools perf kwork: Implement 'report' subcommand 2022-07-26 16:30:05 -03:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking 2022-06-09 10:52:20 -04:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap cxl fixes for 5.19-rc6 2022-07-08 12:55:25 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ARM/PALM TREO SUPPORT orphan 2022-07-07 15:17:00 +02:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS spi: Fixes for v5.19 2022-07-15 10:23:43 -07:00
Makefile Linux 5.19-rc7 2022-07-17 13:30:22 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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 Restructured Text 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.