[PATCH v3 0/4] perf script: Add script per-event-dump support

[ufo19890607 <ufo19890607@gmail.com>]

From: yuzhoujian <yuzhoujian@didichuxing.com>

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 two elements for perf_tool struct, and add three elements for
    	perf_evsel struct, and add the per-event-dump option for perf script.
Patch 2: Add fp argument to print functions
Patch 3: Replace printf with fprintf for all print functions
Patch 4: Make all print functions receive the fp argument, open and close the
    	dump_event file for each evsel, and calculate the dump_event file's size.

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 | 467 +++++++++++++++++++++++++-------------------
 tools/perf/util/evsel.h     |   4 +
 tools/perf/util/session.c   |  16 +-
 tools/perf/util/tool.h      |   3 +
 4 files changed, 286 insertions(+), 204 deletions(-)

-- 
1.8.3.1