[PATCH v4 0/4] perf script: Add script per-event-dump support

[yuzhoujian]

Introduce a new option to print trace output to files named by the
monitored events and update perf-script documentation accordingly.

Shown below is output of perf script command with the newly introduced
option.

         $perf record -e cycles -e cs -ag -- sleep 1
         $perf script --per-event-dump
         [ perf script: Wrote 0.051 MB perf.data-script-dump-cycles.txt (76 samples) ]
         [ perf script: Wrote 0.012 MB perf.data-script-dump-cs.txt (69 samples) ]
         $ls
         perf.data-script-dump-cycles.txt perf.data-script-dump-cs.txt

Without per-event-dump support, drawing flamegraphs for different events
would be a very troublesome thing. You can monitor only one event at a time
if you want to get flamegraphs for different events. Using this option, you
can get the trace output files named by the monitored events, and could draw
flamegraphs according to the event's name.

yuzhoujian (4):
Patch 1: Add new elements for per-event-dump option
Patch 2: Add fp argument to print functions
Patch 3: Replace printf with fprintf for all print functions
Patch 4: Add the fp_selection_helper to set the fp for print functions

Changes since v3:
- Patch 1: - remove three elements for perf_evsel struct and create the perf_script_evsel 
 struct to save them.
- Patch 2: None
- Patch 3: None
- Patch 4: Free the evsel->priv by zfree().

Changes since v2:
- Patch 1: Add the last_evsel_name for per_tool struct and three elements for perf_evsel struct.
- Patch 2: None
- Patch 3: None
- Patch 4: Remove the file_name and per_event_dump_file variables.
           Add the fp_selection_helper function to select the fp and open the dump file
 for all print functions.
           Close the dump file for all the evsels and calculate the dump file's size at
 the end of the perf script.
           Solve the segmentation fault generated by perf script --per-event-dump --show-mmap-events

Changes since v1:
- Patch 1: Remove the set of script.tool.per_event_dump variable.
- Patch 2: Add the __maybe_unused attribute for the fp argument in the second patch.
- Patch 3: remove the fp_selection_helper function for setting the fp argument.
- Patch 2: split the original second patch(Makes all those related functions receive
 the FILE pointer) to two patches.
- Patch 4: modify the file name of per-event-dump to
 <ORIGINAL PERF DATA FILE NAME>-script-dump-<EVENT NAME>.txt

 tools/perf/builtin-script.c | 489 ++++++++++++++++++++++++++------------------
 tools/perf/util/evsel.h     |  12 ++
 tools/perf/util/session.c   |  20 +-
 tools/perf/util/tool.h      |   2 +
 4 files changed, 319 insertions(+), 204 deletions(-)

-- 
1.8.3.1