This patch set is a preparation to support overwritable ring buffer. However, even without the kernel side core patch [1] is accept this patch set is still useful.
With this patch set, perf switches output when receiving SIGUSR2. For example: # perf record -a -F99 --switch-output & [1] 26435 # kill -s SIGUSR2 26435 [ perf record: dump data: Woken up 1 times ] # [ perf record: Dump perf.data.2016041323544373 ] # kill -s SIGUSR2 26435 [ perf record: dump data: Woken up 1 times ] # [ perf record: Dump perf.data.2016041323544730 ] # fg perf record -a -F99 --switch-output ^C[ perf record: Woken up 1 times to write data ] [ perf record: Dump perf.data.2016041323545019 ] [ perf record: Captured and wrote 0.395 MB perf.data.<timestamp> ] User can periodically generates perf trace with a simple script, then remove most of them, only keeps scripts collected when something unusual is detected. After [1], perf can be totally silent before receiving SIGUSR2. Trace is collected in kernel overwritable ring buffer, and dumpped when SIGUSR2 is received. [1] http://lkml.kernel.org/r/1459865478-53413-1-git-send-email-wangn...@huawei.com Cc: Wang Nan <wangn...@huawei.com> Cc: He Kuang <heku...@huawei.com> Cc: Arnaldo Carvalho de Melo <a...@redhat.com> Cc: Jiri Olsa <jo...@kernel.org> Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Zefan Li <lize...@huawei.com> Cc: pi3or...@163.com Wang Nan (10): perf tools: Make ordered_events reusable perf tools: Add perf_data_file__switch() helper perf record: Turns auxtrace_snapshot_enable into 3 states perf record: Add '--timestamp-filename' option to append timestamp to output filename 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 perf core: Add backward attribute to perf event include/linux/perf_event.h | 28 +++++- include/uapi/linux/perf_event.h | 3 +- kernel/events/core.c | 48 ++++++++- kernel/events/ring_buffer.c | 16 ++- tools/perf/builtin-record.c | 208 +++++++++++++++++++++++++++++++++++---- tools/perf/util/data.c | 41 ++++++++ tools/perf/util/data.h | 11 ++- tools/perf/util/ordered-events.c | 9 ++ tools/perf/util/ordered-events.h | 1 + tools/perf/util/session.c | 6 +- 10 files changed, 341 insertions(+), 30 deletions(-) -- 1.8.3.4
