[PATCH 00/17] perf tools: Support overwritable ring buffer

[Wang Nan]

This patch set enables daemonized perf recording by utilizing
overwritable backward ring buffer. With this feature one can
put perf background, and dump ring buffer records by a SIGUSR2
when he/she find something unusual. For example, following
command record system calls, schedule events and samples on cpu cycles
continously:

 # perf record -g -e cycles -e raw_syscalls:*/call-graph=no/ \
                  -e sched:sched_switch/call-graph=no/ \
                  --switch-output --overwrite -a

Then by sending SIGUSR2 to perf when lagging is happen, we get multiple
perf.data output, each of them correspond a abnormal event, and the data
size is reasonable:

 # ls -l ./perf.data*
 -rw------- 1 root root 5122165 May 13 23:51 ./perf.data.2016051323511683
 -rw------- 1 root root 5135093 May 13 23:51 ./perf.data.2016051323512107
 -rw------- 1 root root 5135213 May 13 23:51 ./perf.data.2016051323512215
 -rw------- 1 root root 5135157 May 13 23:51 ./perf.data.2016051323512387

Wang Nan (17):
  perf tools: Extract __perf_evlist__mmap_read()
  perf tools: Add evlist channel helpers
  perf tools: Automatically add new channel according to evlist
  perf tools: Operate multiple channels
  perf record: Prevent reading invalid data in record__mmap_read
  perf tools: Squash overwrite setting into channel
  perf record: Don't read from and poll overwrite channel
  perf record: Don't poll on overwrite channel
  perf tools: Detect avalibility of write_backward
  perf tools: Enable overwrite settings
  perf tools: Set write_backward attribut bit for overwrite events
  perf tools: Record fd into perf_mmap
  perf tools: Add API to pause a channel
  perf record: Rename variable to make code clear
  perf record: Read from backward ring buffer
  perf record: Toggle overwrite ring buffer for reading
  perf tools: Don't warn about out of order event if write_backward is
    used

 tools/perf/builtin-record.c    | 207 +++++++++++++++++++++++--
 tools/perf/perf.h              |   2 +
 tools/perf/util/evlist.c       | 332 ++++++++++++++++++++++++++++++++++++-----
 tools/perf/util/evlist.h       |  67 ++++++++-
 tools/perf/util/evsel.c        |  17 +++
 tools/perf/util/evsel.h        |   3 +
 tools/perf/util/parse-events.c |  20 ++-
 tools/perf/util/parse-events.h |   2 +
 tools/perf/util/parse-events.l |   2 +
 tools/perf/util/record.c       |  11 ++
 tools/perf/util/session.c      |  22 ++-
 11 files changed, 625 insertions(+), 60 deletions(-)

Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx

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1.8.3.4