Support displaying the average IPC and IPC coverage per symbol in 'perf
report' --tui and --stdio modes.

For example,

 $ perf record -b ...
 $ perf report -s symbol

 Overhead  Symbol                           IPC   [IPC Coverage]
   39.60%  [.] __random                     2.30  [ 54.8%]
   18.02%  [.] main                         0.43  [ 54.3%]
   14.21%  [.] compute_flag                 2.29  [100.0%]
   14.16%  [.] rand                         0.36  [100.0%]
    7.06%  [.] __random_r                   2.57  [ 70.5%]
    6.85%  [.] rand@plt                     0.00  [  0.0%]

Jiri Olsa <jolsa@redhat.com> provided the patch to support the --stdio
mode. I merged Jiri's code in this patch.

  $ perf report -s symbol --stdio

    # Overhead  Symbol                       IPC   [IPC Coverage]
    # ........  ...........................  ....................
    #
      39.60%  [.] __random                   2.30  [ 54.8%]
      18.02%  [.] main                       0.43  [ 54.3%]
      14.21%  [.] compute_flag               2.29  [100.0%]
      14.16%  [.] rand                       0.36  [100.0%]
       7.06%  [.] __random_r                 2.57  [ 70.5%]
       6.85%  [.] rand@plt                   0.00  [  0.0%]
       0.02%  [k] run_timer_softirq          1.60  [ 57.2%]

The columns "IPC" and "[IPC Coverage]" are automatically enabled when
the sort-key "symbol" is specified. If the perf.data file doesn't
contain timed LBR information, columns are filled with "-".

For example,

  # Overhead  Symbol                       IPC   [IPC Coverage]
  # ........  ...........................  ....................
  #
      46.57%  [.] main                     -      -
      17.60%  [.] rand                     -      -
      15.84%  [.] __random_r               -      -
      11.90%  [.] __random                 -      -
       6.50%  [.] compute_flag             -      -
       1.59%  [.] rand@plt                 -      -
       0.00%  [.] _dl_relocate_object      -      -
       0.00%  [k] tlb_flush_mmu            -      -
       0.00%  [k] perf_event_mmap          -      -
       0.00%  [k] native_sched_clock       -      -
       0.00%  [k] intel_pmu_handle_irq_v4  -      -
       0.00%  [k] native_write_msr         -      -

 v3:
 ---
 Removed the sortkey 'ipc' from command-line. The columns "IPC"
 and "[IPC Coverage]" are automatically enabled when "symbol"
 is specified.

 v2:
 ---
 Merge in Jiri's patch to support stdio mode
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1543586097-27632-4-git-send-email-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>