linux-kernel - Re: [PATCH 2/3] find: micro-optimize for_each_{set,clear}

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Message-ID: <YM3L6fAhEmgYgle7@smile.fi.intel.com>
Date:   Sat, 19 Jun 2021 13:50:17 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Yury Norov <yury.norov@...il.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Russell King <linux+etnaviv@...linux.org.uk>,
        Christian Gmeiner <christian.gmeiner@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Marc Zyngier <maz@...nel.org>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Wei Yang <richard.weiyang@...ux.alibaba.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Alexey Klimov <aklimov@...hat.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, etnaviv@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, linux-hwmon@...r.kernel.org
Subject: Re: [PATCH 2/3] find: micro-optimize for_each_{set,clear}_bit()

On Fri, Jun 18, 2021 at 12:57:34PM -0700, Yury Norov wrote:
> The macros iterate thru all set/clear bits in a bitmap. They search a
> first bit using find_first_bit(), and the rest bits using find_next_bit().
> 
> Since find_next_bit() is called shortly after find_first_bit(), we can
> save few lines of I-cache by not using find_first_bit().

Any number available?

-- 
With Best Regards,
Andy Shevchenko