This patch set has been posted multiple times (with and without corresponding 'perf tool' patches), and doesn't receive further comment. I think it should be okay to merge them into mainline. There are many perf's improvement depend on it. However, Peter is not responsive after I fixed some problems he pointed out.
Introduces 'write_backward' into perf_event_attr, allows kernel writing the ring buffer from the end of it. This feature allows extracting data from overwritable ring buffer. Wang Nan (5): perf core: Introduce new ioctl options to pause and resume ring buffer perf core: Set event's default overflow_handler perf core: Prepare writing into ring buffer from end perf core: Add backward attribute to perf event perf core: Reduce perf event output overhead by new overflow handler include/linux/perf_event.h | 22 +++++++++++-- include/uapi/linux/perf_event.h | 4 ++- kernel/events/core.c | 73 +++++++++++++++++++++++++++++++++++------ kernel/events/internal.h | 11 +++++++ kernel/events/ring_buffer.c | 63 +++++++++++++++++++++++++++++++---- 5 files changed, 153 insertions(+), 20 deletions(-) Cc: He Kuang <[email protected]> Cc: Alexei Starovoitov <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Brendan Gregg <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Zefan Li <[email protected]> Cc: [email protected] -- 1.8.3.4
