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Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end

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On 2016/3/24 3:25, Alexei Starovoitov wrote:
> On Wed, Mar 23, 2016 at 06:08:41PM +0800, Wangnan (F) wrote:
>>
>> On 2016/3/23 17:50, Peter Zijlstra wrote:
>>> On Mon, Mar 14, 2016 at 09:59:43AM +0000, Wang Nan wrote:
>>>> Convert perf_output_begin to __perf_output_begin and make the later
>>>> function able to write records from the end of the ring buffer.
>>>> Following commits will utilize the 'backward' flag.
>>>>
>>>> This patch doesn't introduce any extra performance overhead since we
>>>> use always_inline.
>>> So while I agree that with __always_inline and constant propagation we
>>> _should_ end up with the same code, we have:
>>>
>>> $ size defconfig-build/kernel/events/ring_buffer.o.{pre,post}
>>>     text    data     bss     dec     hex filename
>>>     3785       2       0    3787     ecb defconfig-build/kernel/events/ring_buffer.o.pre
>>>     3673       2       0    3675     e5b defconfig-build/kernel/events/ring_buffer.o.post
>>>
>>> The patch actually makes the file shrink.
>>>
>>> So I think we still want to have some actual performance numbers.
>> There are some numbers. You can find them from:
>>
>> http://lkml.iu.edu/hypermail/linux/kernel/1601.2/03966.html
> Wang, when you respin, please add all perf analysis that you've
> done and the reasons to do it this way to commit log
> to make sure it stays in git history.
>
> I've reviewed it in the past and looks like the patches didn't
> change over the last months. So still ack, I believe
> overwrite buffers is a great feature.
Can I add your Acked-by in all these 5 patches?

Thank you.

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Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end Peter Zijlstra <peterz@infradead.org> - 2016-03-23 11:00 +0100
  Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end "Wangnan (F)" <wangnan0@huawei.com> - 2016-03-23 11:10 +0100
    Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2016-03-23 20:30 +0100
      Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end "Wangnan (F)" <wangnan0@huawei.com> - 2016-03-24 05:00 +0100
        Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2016-03-24 18:40 +0100
  Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end "Wangnan (F)" <wangnan0@huawei.com> - 2016-03-25 13:30 +0100
    Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end "Wangnan (F)" <wangnan0@huawei.com> - 2016-03-25 13:40 +0100
      Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end "Wangnan (F)" <wangnan0@huawei.com> - 2016-03-25 15:20 +0100
        Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end Peter Zijlstra <peterz@infradead.org> - 2016-03-27 17:30 +0200
          Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end pi3orama <pi3orama@163.com> - 2016-03-27 17:40 +0200
            Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end "Wangnan (F)" <wangnan0@huawei.com> - 2016-03-28 03:10 +0200
              Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end "Wangnan (F)" <wangnan0@huawei.com> - 2016-03-28 04:10 +0200
                Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end "Wangnan (F)" <wangnan0@huawei.com> - 2016-03-28 05:00 +0200

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