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David Carrillo-Cisneros 64831a21db perf sort: Use default sort if evlist is empty
Fixes bug noted by Jiri in https://lkml.org/lkml/2017/6/13/755 and
caused by commit d49dadea78 ("perf tools: Make 'trace' or
'trace_fields' sort key default for tracepoint events") not taking into
account that evlist is empty in pipe-mode.

Before this commit, pipe mode will only show bogus "100.00%  N/A"
instead of correct output as follows:

  $ perf record -o - sleep 1 | perf report -i -
  # To display the perf.data header info, please use --header/--header-only options.
  #
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.000 MB - ]
  #
  # Total Lost Samples: 0
  #
  # Samples: 8  of event 'cycles:ppH'
  # Event count (approx.): 145658
  #
  # Overhead  Trace output
  # ........  ............
  #
     100.00%  N/A

Correct output, after patch:

  $ perf record -o - sleep 1 | perf report -i -
  # To display the perf.data header info, please use --header/--header-only options.
  #
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.000 MB - ]
  #
  # Total Lost Samples: 0
  #
  # Samples: 8  of event 'cycles:ppH'
  # Event count (approx.): 191331
  #
  # Overhead  Command  Shared Object      Symbol
  # ........  .......  .................  .................................
  #
      81.63%  sleep    libc-2.19.so       [.] _exit
      13.58%  sleep    ld-2.19.so         [.] do_lookup_x
       2.34%  sleep    [kernel.kallsyms]  [k] context_switch
       2.34%  sleep    libc-2.19.so       [.] __GI___libc_nanosleep
       0.11%  perf     [kernel.kallsyms]  [k] __intel_pmu_enable_a

Reported-by: Jiri Olsa <jolsa@kernel.org>
Report-Link: https://lkml.kernel.org/r/20170613185422.GA6092@krava
Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Turner <pjt@google.com>
Cc: Simon Que <sque@chromium.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: d49dadea78 ("perf tools: Make 'trace' or 'trace_fields' sort key default for tracepoint events")
Link: https://lkml.kernel.org/r/20170721051157.47331-1-davidcc@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-07-26 17:00:07 -03:00
Documentation Merge branch 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 18:33:03 -07:00
arch perf/core improvements and fixes: 2017-07-20 10:31:52 +02:00
block Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 16:50:31 -07:00
certs scripts/spelling.txt: add "intialise(d)" pattern and fix typo instances 2017-05-08 17:15:13 -07:00
crypto crypto : asymmetric_keys : verify_pefile:zero memory content before freeing 2017-06-09 13:29:50 +10:00
drivers Merge branch 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 18:33:03 -07:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 13:08:04 -07:00
include perf/core: Define the common branch type classification 2017-07-18 23:14:38 -03:00
init Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 13:08:04 -07:00
ipc mm: introduce kv[mz]alloc helpers 2017-05-08 17:15:12 -07:00
kernel perf/core: Fix scheduling regression of pinned groups 2017-07-20 09:43:02 +02:00
lib Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 13:08:04 -07:00
mm Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 14:45:09 -07:00
net Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 13:08:04 -07:00
samples samples/bpf: run cleanup routines when receiving SIGTERM 2017-05-11 21:43:30 -04:00
scripts Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 11:34:53 -07:00
security Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 13:08:04 -07:00
sound Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 13:08:04 -07:00
tools perf sort: Use default sort if evlist is empty 2017-07-26 17:00:07 -03:00
usr initramfs: fix disabling of initramfs (and its compression) 2017-06-02 15:07:37 -07:00
virt sched/wait: Rename wait_queue_t => wait_queue_entry_t 2017-06-20 12:18:27 +02:00
.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 kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 12:14:18 -07:00
Makefile Linux 4.12 2017-07-02 16:07:02 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

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.