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Re: [PATCH 0/6] perf core: Read from overwrite ring buffer

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Hi,

On Tue, Jan 19, 2016 at 11:16:44AM +0000, Wang Nan wrote:
> This patchset introduces two methods to support reading from overwrite.
> 
>  1) Tailsize: write the size of an event at the end of it
>  2) Backward writing: write the ring buffer from the end of it to the
>     beginning.

So both of two methods should be used together?

Thanks,
Namhyung


> 
> Patch 1/6 introduces a new ioctl operation to pause and resume ring
> buffer since reading from a overwrite ring buffer is not reliable.
> 
> To reduce overhead as much as possible, force setting overflow_handler
> and create specific function for backward writing and onward writing.
> 
> Cc: He Kuang <hekuang@huawei.com>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Zefan Li <lizefan@huawei.com>
> Cc: pi3orama@163.com
> 
> Wang Nan (6):
>   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 backwork attribute to perf event
>   perf core: Reduce perf event output overhead by setting overwrite
>     handler
>   perf/core: Put size of a sample at the end of it by
>     PERF_SAMPLE_TAILSIZE
> 
>  include/linux/perf_event.h      |  39 +++++++---
>  include/uapi/linux/perf_event.h |   7 +-
>  kernel/events/core.c            | 155 +++++++++++++++++++++++++++++++---------
>  kernel/events/internal.h        |  11 +++
>  kernel/events/ring_buffer.c     |  65 ++++++++++++++---
>  5 files changed, 223 insertions(+), 54 deletions(-)
> 
> -- 
> 1.8.3.4
> 

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Thread

[PATCH] perf core: Introduce new ioctl options to pause and resume ring buffer Wang Nan <wangnan0@huawei.com> - 2016-01-18 13:00 +0100
  Re: [PATCH] perf core: Introduce new ioctl options to pause and  resume ring buffer Peter Zijlstra <peterz@infradead.org> - 2016-01-18 13:10 +0100
    Re: [PATCH] perf core: Introduce new ioctl options to pause and resume  ring buffer "Wangnan (F)" <wangnan0@huawei.com> - 2016-01-19 04:00 +0100
    [PATCH 0/6] perf core: Read from overwrite ring buffer Wang Nan <wangnan0@huawei.com> - 2016-01-19 12:20 +0100
      [PATCH 1/6] perf core: Introduce new ioctl options to pause and resume ring buffer Wang Nan <wangnan0@huawei.com> - 2016-01-19 12:20 +0100
      [PATCH 6/6] perf/core: Put size of a sample at the end of it by PERF_SAMPLE_TAILSIZE Wang Nan <wangnan0@huawei.com> - 2016-01-19 12:20 +0100
      [PATCH 2/6] perf core: Set event's default overflow_handler Wang Nan <wangnan0@huawei.com> - 2016-01-19 12:20 +0100
      [PATCH 5/6] perf core: Reduce perf event output overhead by setting overwrite handler Wang Nan <wangnan0@huawei.com> - 2016-01-19 12:20 +0100
      [PATCH 4/6] perf core: Add backwork attribute to perf event Wang Nan <wangnan0@huawei.com> - 2016-01-19 12:20 +0100
      [PATCH 3/6] perf core: Prepare writing into ring buffer from end Wang Nan <wangnan0@huawei.com> - 2016-01-19 12:30 +0100
      Re: [PATCH 0/6] perf core: Read from overwrite ring buffer Namhyung Kim <namhyung@kernel.org> - 2016-01-19 15:10 +0100
        Re: [PATCH 0/6] perf core: Read from overwrite ring buffer pi3orama <pi3orama@163.com> - 2016-01-19 15:20 +0100
      Re: [PATCH 0/6] perf core: Read from overwrite ring buffer Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2016-01-19 18:50 +0100
        Re: [PATCH 0/6] perf core: Read from overwrite ring buffer "Wangnan (F)" <wangnan0@huawei.com> - 2016-01-20 02:40 +0100
          Re: [PATCH 0/6] perf core: Read from overwrite ring buffer Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2016-01-20 03:30 +0100
            Re: [PATCH 0/6] perf core: Read from overwrite ring buffer "Wangnan (F)" <wangnan0@huawei.com> - 2016-01-21 08:00 +0100
              Re: [PATCH 0/6] perf core: Read from overwrite ring buffer "Wangnan (F)" <wangnan0@huawei.com> - 2016-01-22 03:30 +0100
                Re: [PATCH 0/6] perf core: Read from overwrite ring buffer Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2016-01-22 04:30 +0100
                Re: [PATCH 0/6] perf core: Read from overwrite ring buffer "Wangnan (F)" <wangnan0@huawei.com> - 2016-01-22 05:50 +0100

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