[PATCH v2 0/6] perf tools: Use SIGUSR2 control data dumpping

[Wang Nan <wangnan0@huawei.com>]

This patch set is based on perf/core.

v1 -> v2: Fix a bug which triggers output switching without
          '--switch-output' provided.

Patch 5/10 in v1 has a bug: with following cmdline:
 # perf record -e intel_bts// --per-thread --snapshot -p 13588

Sending 'SIGUSR2' to perf triggers output switching, which us
undesirable. The reason is in signal handler perf doesn't consider if
user provided --switch-output explicitly.

With this patchset applied:

 # /perf record --switch-output -e intel_bts// --per-thread --snapshot -p 13588 &
 [1] 15116
 # kill -s SIGUSR2 15116
 # [ perf record: dump data: Woken up 5 times ]
 [ perf record: Dump perf.data.2016041506170000 ]
 
 # kill -s SIGUSR2 15116
 # [ perf record: dump data: Woken up 3 times ]
 [ perf record: Dump perf.data.2016041506170447 ]
 
 # fg
 /perf record --switch-output -e intel_bts// --per-thread --snapshot -p 13588
 ^C[ perf record: Woken up 3 times to write data ]
 [ perf record: Dump perf.data.2016041506170785 ]
 [ perf record: Captured and wrote 0.012 MB perf.data.<timestamp> ]
 
 # ls -l ./perf.data*
 -rw------- 1 root root 4212888 Apr 15 06:17 ./perf.data.2016041506170000
 -rw------- 1 root root 4212704 Apr 15 06:17 ./perf.data.2016041506170447
 -rw------- 1 root root   18368 Apr 15 06:17 ./perf.data.2016041506170785

The first 2 perf.data works fine. The final one has no samples.

And:
 # rm ./perf.data*
 # /perf record -e intel_bts// --per-thread --snapshot -p 13588 &
 [1] 15396
 # kill -s SIGUSR2 15396
 # kill -s SIGUSR2 15396
 # fg
 /perf record -e intel_bts// --per-thread --snapshot -p 13588
 ^C[ perf record: Woken up 9 times to write data ]
 [ perf record: Captured and wrote 8.012 MB perf.data ]
 
 # ls -l ./perf.data*
 -rw------- 1 root root 8417552 Apr 15 06:20 ./perf.data

(In v1, the second test trigger output switching incorrectly)

Patch 1-2/6 in this patchset makes switch output trigger similar to
auxtrace snapshot trigger. Patch 1/6 introduces a 'trigger' class for
them. It would be better to merge patch 1/6 with commit c0bdc1c ("perf
record: Turns auxtrace_snapshot_enable into 3 states"). However, Ingo
has collected that commit, so make it a separated patch.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Cc: He Kuang <hekuang@huawei.com>

Wang Nan (6):
  perf tools: Extrace trigger class from auxtrace_snapshot
  perf record: Split output into multiple files via '--switch-output'
  perf record: Force enable --timestamp-filename when --switch-output is
    provided
  perf record: Disable buildid cache options by default in switch output
    mode
  perf record: Re-synthesize tracking events after output switching
  perf record: Generate tracking events for process forked by perf

 tools/perf/builtin-record.c | 147 +++++++++++++++++++++++++++++++-------------
 tools/perf/util/util.h      |  60 ++++++++++++++++++
 2 files changed, 163 insertions(+), 44 deletions(-)

-- 
1.8.3.4