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Re: [PATCH] sched: remove sched_find_first_bit()

From Ingo Molnar <mingo@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH] sched: remove sched_find_first_bit()
Date 2017-05-16 10:40 +0200
Message-ID <tHGbn-3ia-5@gated-at.bofh.it> (permalink)
References <tH67U-4Wy-19@gated-at.bofh.it> <tH67U-4Wy-17@gated-at.bofh.it> <tHqJk-1Wb-11@gated-at.bofh.it>
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* Yury Norov <ynorov@caviumnetworks.com> wrote:

> I collected about 700 results in dmesg, and took 600 fastest.
> For the vanilla kernel, the average value is 368, and for patched
> kernel it is 388. It's 5% slower. But the standard deviation is 
> really big for both series' - 131 and 106 cycles respectively, which
> is ~ 30%. And so, my conclusion is: there's no benefit in using
> sched_find_first_bit() comparing to find_first_bit().

Erm, so you in essence claim:

	"according to measurements the new code is 5% slower, with a high, 30% 
	 stddev, hence the new code is better!"

Basic logic fail...

Thanks,

	Ingo

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Thread

Re: [PATCH] sched: remove sched_find_first_bit() Ingo Molnar <mingo@kernel.org> - 2017-05-14 20:10 +0200
  Re: [PATCH] sched: remove sched_find_first_bit() Arnd Bergmann <arnd@arndb.de> - 2017-05-15 18:10 +0200
    Re: [PATCH] sched: remove sched_find_first_bit() Arnd Bergmann <arnd@arndb.de> - 2017-05-15 22:40 +0200
      Re: [PATCH] sched: remove sched_find_first_bit() Arnd Bergmann <arnd@arndb.de> - 2017-05-15 23:10 +0200
  Re: [PATCH] sched: remove sched_find_first_bit() Ingo Molnar <mingo@kernel.org> - 2017-05-16 10:40 +0200
    Re: [PATCH] sched: remove sched_find_first_bit() Ingo Molnar <mingo@kernel.org> - 2017-05-18 09:20 +0200

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