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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Yury Norov <yury.norov@gmail.com>,
	"Vaittinen, Matti" <Matti.Vaittinen@fi.rohmeurope.com>,
	Matti Vaittinen <mazziesaccount@gmail.com>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Mark Brown <broonie@kernel.org>, Jiri Kosina <trivial@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Kumar Kartikeya Dwivedi <memxor@gmail.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] bitops: Add single_bit_set()
Date: Tue, 23 Nov 2021 10:10:46 +0100	[thread overview]
Message-ID: <CAMuHMdXHVxY+BGct2fC+jZ--jOXP0w7yabJOwYED-_1RANM0JA@mail.gmail.com> (raw)
In-Reply-To: <YZyubUvWW98ThOPe@smile.fi.intel.com>

Hi Andy,

On Tue, Nov 23, 2021 at 10:04 AM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> Be sure you get better assembly in these cases. As I have told already,
> hweight() is a single assembly instruction, I'm not sure open coded variant

... on a select set of architectures.

Do we need CONFIG_HAVE_FAST_HWEIGHT?

> may be better even for long bitmaps. That said, assembly comparison and
> some performance tests would be nice to have.

> As an API per se it might make sense to have such, but you know that we don't
> add it without users.

Indeed. And code for unused APIs increase kernel size, too
(without LTO).

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

  reply	other threads:[~2021-11-23  9:11 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-22 11:03 [PATCH 0/4] Provide event map helper for regulator drivers Matti Vaittinen
2021-11-22 11:03 ` [PATCH 1/4] bitops: Add single_bit_set() Matti Vaittinen
2021-11-22 11:28   ` Andy Shevchenko
2021-11-22 12:42     ` Vaittinen, Matti
2021-11-22 12:57       ` Andy Shevchenko
2021-11-22 13:00         ` Andy Shevchenko
2021-11-22 13:18         ` Vaittinen, Matti
2021-11-23 10:42           ` David Laight
2021-11-23 10:47             ` Andy Shevchenko
2021-11-23 10:58               ` David Laight
2021-11-23 13:43                 ` 'Andy Shevchenko'
2021-11-23 14:36                   ` David Laight
2021-11-23 11:42             ` Vaittinen, Matti
2021-11-22 17:54         ` Yury Norov
2021-11-22 19:56           ` Andy Shevchenko
2021-11-23  7:51             ` Yury Norov
2021-11-23  5:26           ` Vaittinen, Matti
2021-11-23  7:33             ` Yury Norov
2021-11-23  9:03               ` Andy Shevchenko
2021-11-23  9:10                 ` Geert Uytterhoeven [this message]
2021-11-22 11:03 ` [PATCH 2/4] regulators: Add regulator_err2notif() helper Matti Vaittinen
2021-11-22 11:04 ` [PATCH 3/4] regulators: irq_helper: Provide helper for trivial IRQ notifications Matti Vaittinen
2021-11-22 11:48   ` Andy Shevchenko
2021-11-22 12:44     ` Vaittinen, Matti
2021-11-22 11:04 ` [PATCH 4/4] regulator: Drop unnecessary struct member Matti Vaittinen

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