[PATCH 0/2] perf: Allow closing siblings' file descriptors

[Alexander Shishkin <alexander.shishkin@linux.intel.com>]

Hi guys,

I've been looking at reducing the number of open file descriptors per perf
session. If we retain one descriptor per event, in a large group they add
up. At the same time, we're not actually using them for anything after the
SET_OUTPUT and maybe SET_FILTER ioctls. So, this series is a stab at that.

So, I added a new flag to the perf_event_open() that tells perf to keep
the event around after its file descriptor gets closed, for as long as its
group leader is alive. Since this is a new behavior, the flag is an opt-in.

I also hacked this into the perf tool (mostly perf record, but I'll hack
stat as well if this general approach is agreeable).

Alexander Shishkin (2):
  perf: Add closing sibling events' file descriptors
  perf record: Support closing siblings' file descriptors

 include/linux/perf_event.h              |   7 ++
 include/uapi/linux/perf_event.h         |   1 +
 kernel/events/core.c                    | 149 +++++++++++++++++-------
 tools/include/uapi/linux/perf_event.h   |   1 +
 tools/lib/perf/evlist.c                 |  30 ++++-
 tools/lib/perf/evsel.c                  |  21 ++++
 tools/lib/perf/include/internal/evsel.h |   4 +
 tools/perf/builtin-record.c             |  48 ++++++--
 tools/perf/util/cpumap.c                |   4 +
 tools/perf/util/evlist.c                |   4 +-
 tools/perf/util/evsel.c                 |  17 ++-
 tools/perf/util/evsel.h                 |   3 +
 12 files changed, 234 insertions(+), 55 deletions(-)

-- 
2.27.0