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.
