perf tools: Fix display of first level of callchains

The callchain stdio mode display was written using a sorted by symbol
report. In this mode we have only one callchain root per hist so we
forgot to handle cases where we have multiple callchain root, as in per
dso sorting for example.

Fix this by handling these roots like any other branch, with the hist as
the parent.

Before:

     1.97%  libpthread-2.12.1.so
            |
            --- __libc_write
                create_worker
                bench_sched_messaging
                cmd_bench
                run_builtin
                main
                __libc_start_main

            |
            --- __libc_read
                create_worker
                bench_sched_messaging
                cmd_bench
                run_builtin
                main
                __libc_start_main

After:

     1.97%  libpthread-2.12.1.so
            |
            |--36.97%-- __libc_write
            |          create_worker
            |          bench_sched_messaging
            |          cmd_bench
            |          run_builtin
            |          main
            |          __libc_start_main
            |
            |--31.47%-- __libc_read
            |          create_worker
            |          bench_sched_messaging
            |          cmd_bench
            |          run_builtin
            |          main
            |          __libc_start_main
           ...

Single roots keep their entry without percentage because they have
the same overhead than the hist they refer to. ie: 100% in fractal
mode and the percentage of the hist in graph mode:

     0.00%  [k] reschedule_interrupt
            |
            --- default_idle
                amd_e400_idle
                cpu_idle
                start_secondary

Reported-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions