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Date:   Thu, 9 Sep 2021 21:49:29 +0800
From:   Jisheng Zhang <jszhang3@mail.ustc.edu.cn>
To:     Kefeng Wang <wangkefeng.wang@huawei.com>
Cc:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        <linux-riscv@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] riscv: enable GENERIC_FIND_FIRST_BIT
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        <20210908230427.3a92fb87@xhacker>
        <bbd220c4-b535-d024-6bd3-b620b4702ed3@huawei.com>
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On Thu, 9 Sep 2021 08:58:31 +0800
Kefeng Wang <wangkefeng.wang@huawei.com> wrote:

> On 2021/9/8 23:04, Jisheng Zhang wrote:
> > Hi Palmer,
> >
> > On Sun, 18 Jul 2021 00:14:23 +0800
> > Jisheng Zhang wrote:
> > =20
> >> From: Jisheng Zhang <jszhang@kernel.org>
> >>
> >> riscv doesn't implement architecture-optimized bitsearching functions
> >> such as find_first_{zero}_bit() etc.
> >>
> >> When GENERIC_FIND_FIRST_BIT=3Dn, find_first_bit() is implemented with
> >> find_next_bit() which is less efficient. Enable GENERIC_FIND_FIRST_BIT
> >> for riscv to get more optimized find_first_bit() implementation, an
> >> initial test(lib/find_bit_benchmark) shows find_first_bit() performance
> >> is improved by nearly 32%. =20
> > It seems this patch is missed. Is it possible to pick it up for 2nd 5.1=
5-rc1 PR?
> >
> > Thanks =20
>=20
> It is enabled unconditionally by following commit
>=20
> commit dbbccfe505ef8fae804677abf0564c1e07479102
>=20
> Author: Yury Norov <yury.norov@gmail.com>
> Date:=C2=A0=C2=A0 Tue Aug 24 09:59:56 2021 +1000
>=20
>  =C2=A0=C2=A0=C2=A0 arch: remove GENERIC_FIND_FIRST_BIT entirely
>=20

Aha, thanks for the information. After Yury's commit, this patch
is useless now.

thanks