Add '-g/--group' option for showing event groups.  For simplicity it is
currently not compatible with other options.

  $ perf evlist --group
  {ref-cycles,cycles}

  $ perf evlist
  ref-cycles
  cycles
Suggested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1358845787-1350-20-git-send-email-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

There was no easy way to see the frequency used, and with the change of
default, we better provide one.

[root@sandy linux]# perf evlist -F
cycles: sample_freq=4000
[root@sandy linux]# perf evlist -v
cycles: sample_freq=4000, size: 80, sample_type: 391, read_format: 7, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, sample_id_all: 1, exclude_guest: 1
[root@sandy linux]#

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-e1p9poez3nwrgycbmwqmhlsu@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The default input file for perf report is not handled the same way as
perf record does it for its output file. This leads to unexpected
behavior of perf report, etc. E.g.:

 # perf record -a -e cpu-cycles sleep 2 | perf report | cat
 failed to open perf.data: No such file or directory  (try 'perf record' first)

While perf record writes to a fifo, perf report expects perf.data to be
read. This patch changes this to accept fifos as input file.

Applies to the following commands:

 perf annotate
 perf buildid-list
 perf evlist
 perf kmem
 perf lock
 perf report
 perf sched
 perf script
 perf timechart

Also fixes char const* -> const char* type declaration for filename
strings.

v2:
* Prevent potential null pointer access to input_name in
  builtin-report.c. Needed due to removal of patch "perf report: Setup
  browser if stdout is a pipe"

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1323248577-11268-5-git-send-email-robert.richter@amd.comSigned-off-by: NRobert Richter <robert.richter@amd.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

[root@emilia ~]# perf record -a -e sched:* -e timer:timer* sleep 5
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.172 MB perf.data (~7530 samples) ]
[root@emilia ~]# perf evlist
sched:sched_kthread_stop
sched:sched_kthread_stop_ret
sched:sched_wakeup
sched:sched_wakeup_new
sched:sched_switch
sched:sched_migrate_task
sched:sched_process_free
sched:sched_process_exit
sched:sched_wait_task
sched:sched_process_wait
sched:sched_process_fork
sched:sched_stat_wait
sched:sched_stat_sleep
sched:sched_stat_iowait
sched:sched_stat_runtime
sched:sched_pi_setprio
timer:timer_init
timer:timer_start
timer:timer_expire_entry
timer:timer_expire_exit
timer:timer_cancel
[root@emilia ~]#

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>