Arnaldo Carvalho de Melo ecc4c5614b perf tools: Propagate perf_config() errors
Previously these were being ignored, sometimes silently.

Stop doing that, emitting debug messages and handling the errors.

Testing it:

  $ cat ~/.perfconfig
  cat: /home/acme/.perfconfig: No such file or directory
  $ perf stat -e cycles usleep 1

   Performance counter stats for 'usleep 1':

           938,996      cycles:u

       0.003813731 seconds time elapsed

  $ perf top --stdio
  Error:
  You may not have permission to collect system-wide stats.

  Consider tweaking /proc/sys/kernel/perf_event_paranoid,
  <SNIP>
  [ perf record: Captured and wrote 0.019 MB perf.data (7 samples) ]
  [acme@jouet linux]$ perf report --stdio
  # To display the perf.data header info, please use --header/--header-only options.
  # Overhead  Command  Shared Object      Symbol
  # ........  .......  .................  .........................
    71.77%  usleep   libc-2.24.so       [.] _dl_addr
    27.07%  usleep   ld-2.24.so         [.] _dl_next_ld_env_entry
     1.13%  usleep   [kernel.kallsyms]  [k] page_fault
  $
  $ touch ~/.perfconfig
  $ ls -la ~/.perfconfig
  -rw-rw-r--. 1 acme acme 0 Jan 27 12:14 /home/acme/.perfconfig
  $
  $ perf stat -e instructions usleep 1

   Performance counter stats for 'usleep 1':

           244,610      instructions:u

       0.000805383 seconds time elapsed

  $
  [root@jouet ~]# chown acme.acme ~/.perfconfig
  [root@jouet ~]# perf stat -e cycles usleep 1
    Warning: File /root/.perfconfig not owned by current user or root, ignoring it.

   Performance counter stats for 'usleep 1':

           937,615      cycles

       0.000836931 seconds time elapsed
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-j2rq96so6xdqlr8p8rd6a3jx@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-01-27 12:23:33 -03:00
2017-01-18 15:14:15 -07:00
2017-01-11 19:49:27 +01:00
2017-01-17 15:04:59 +01:00
2016-05-23 17:04:14 -07:00

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.
Description
Linux kernel source tree
Readme 3.5 GiB
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