[PATCH v3 00/11] 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

v1 -> v2: Totally redesign: drop the principle of 'channal', use
          auxiliary evlist instead. Fix missing documentation.

v2 -> v3: Rename perf_evlist__toggle_paused() to perf_evlist__pause/resume.

Wang Nan (11):
  perf tools: Add API to pause/resume a evlist
  perf record: Prevent reading invalid data in record__mmap_read
  perf record: Rename variable to make code clear
  perf record: Read from backward ring buffer
  perf evlist: Introduce aux perf evlist
  perf tools: Don't poll and mmap overwritable events
  perf tools: Enable overwrite settings
  perf record: Introduce rec->overwrite_evlist for overwritable events
  perf record: Toggle overwrite ring buffer for reading
  perf tools: Don't warn about out of order event if write_backward is
    used
  perf tools: Check write_backward during evlist config

 tools/perf/Documentation/perf-record.txt |  14 ++
 tools/perf/arch/x86/util/tsc.c           |   2 +
 tools/perf/builtin-record.c              | 354 +++++++++++++++++++++++++++----
 tools/perf/perf.h                        |   1 +
 tools/perf/util/evlist.c                 |  85 ++++++--
 tools/perf/util/evlist.h                 |   6 +
 tools/perf/util/evsel.c                  |  27 ++-
 tools/perf/util/evsel.h                  |  15 ++
 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                 |  17 ++
 tools/perf/util/session.c                |  22 +-
 13 files changed, 498 insertions(+), 69 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