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Ingo Molnar 39ce7fb315 perf report: Show zero counters as well in 'perf report --stat'
When recently using 'perf report --stat' it was not clear to me from the
output whether a particular statistics field (LOST_SAMPLES) was not
present, or just zero:

  fomalhaut:~> perf report --stat

  Aggregated stats:
           TOTAL events:     495984
            MMAP events:         85
            COMM events:       3389
            EXIT events:       1605
        THROTTLE events:          2
      UNTHROTTLE events:          2
            FORK events:       3377
          SAMPLE events:     472629
           MMAP2 events:      14753
  FINISHED_ROUND events:        139
      THREAD_MAP events:          1
         CPU_MAP events:          1
       TIME_CONV events:          1

I had to check the output several times to ascertain that I'm not
misreading the output, that the field didn't change and that I didn't
misremember the name. In fact I had to look into the perf source to make
sure that zero fields are indeed not shown.

With the patch applied:

  fomalhaut:~> perf report --stat

  Aggregated stats:
           TOTAL events:     495984
            MMAP events:         85
            LOST events:          0
            COMM events:       3389
            EXIT events:       1605
        THROTTLE events:          2
      UNTHROTTLE events:          2
            FORK events:       3377
            READ events:          0
          SAMPLE events:     472629
           MMAP2 events:      14753
             AUX events:          0
    ITRACE_START events:          0
    LOST_SAMPLES events:          0
          SWITCH events:          0
 SWITCH_CPU_WIDE events:          0
      NAMESPACES events:          0
            ATTR events:          0
      EVENT_TYPE events:          0
    TRACING_DATA events:          0
        BUILD_ID events:          0
  FINISHED_ROUND events:        139
        ID_INDEX events:          0
   AUXTRACE_INFO events:          0
        AUXTRACE events:          0
  AUXTRACE_ERROR events:          0
      THREAD_MAP events:          1
         CPU_MAP events:          1
     STAT_CONFIG events:          0
            STAT events:          0
      STAT_ROUND events:          0
    EVENT_UPDATE events:          0
       TIME_CONV events:          1
         FEATURE events:          0

It's pretty clear at a glance that LOST_SAMPLES is present but zero.

The original output can still be gotten via:

  fomalhaut:~> perf report --stat | grep -vw 0

  Aggregated stats:
           TOTAL events:     495984
            MMAP events:         85
            COMM events:       3389
            EXIT events:       1605
        THROTTLE events:          2
      UNTHROTTLE events:          2
            FORK events:       3377
          SAMPLE events:     472629
           MMAP2 events:      14753
  FINISHED_ROUND events:        139
      THREAD_MAP events:          1
         CPU_MAP events:          1
       TIME_CONV events:          1

So I don't think there's any real loss in functionality.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20180307152430.7e5h7e657b7bgd7q@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-16 13:55:36 -03:00
arch perf: Fix sibling iteration 2018-03-16 15:34:10 +01:00
block for-linus-20180302 2018-03-02 09:35:36 -08:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto X.509: fix NULL dereference when restricting key with unsupported_sig 2018-02-22 14:38:34 +00:00
Documentation Linux 4.16-rc4 2018-03-06 07:30:22 +01:00
drivers perf: Fix sibling iteration 2018-03-16 15:34:10 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs for-4.16-rc3-tag 2018-03-04 11:04:27 -08:00
include perf: Fix sibling iteration 2018-03-16 15:34:10 +01:00
init jump_label: Explicitly disable jump labels in __init code 2018-02-21 16:54:05 +01:00
ipc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kernel perf/core: Clear sibling list of detached events 2018-03-16 15:34:24 +01:00
lib A single fix for a memory leak regression in the dma-debug code. 2018-02-28 11:13:08 -08:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm mm: don't defer struct page initialization for Xen pv guests 2018-02-21 15:35:43 -08:00
net libceph, ceph: avoid memory leak when specifying same option several times 2018-02-26 16:19:30 +01:00
samples - do not build samples when cross compiling (Michal Hocko) 2018-02-27 10:39:29 -08:00
scripts Kbuild fixes for v4.16 2018-03-03 10:37:01 -08:00
security integrity/security: fix digsig.c build error with header file 2018-02-22 20:09:08 -08:00
sound ALSA: x86: Fix potential crash at error path 2018-02-28 08:46:00 +01:00
tools perf report: Show zero counters as well in 'perf report --stat' 2018-03-16 13:55:36 -03:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: mmu: Fix overlap between public and private memslots 2018-02-24 01:43:36 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: ignore ASN.1 auto generated files 2018-02-14 21:05:38 +01:00
.mailmap mailmap: update Mark Yao's email address 2018-01-04 16:45:09 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Kbuild fixes for v4.16 2018-03-03 10:37:01 -08:00
Makefile Linux 4.16-rc4 2018-03-04 14:54:11 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.