linux-kernel - Re: [PATCH] riscv: enable GENERIC_FIND_FIRST

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Thu, 9 Sep 2021 21:49:29 +0800
From:   Jisheng Zhang <jszhang3@...l.ustc.edu.cn>
To:     Kefeng Wang <wangkefeng.wang@...wei.com>
Cc:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        <linux-riscv@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] riscv: enable GENERIC_FIND_FIRST_BIT

On Thu, 9 Sep 2021 08:58:31 +0800
Kefeng Wang <wangkefeng.wang@...wei.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:
> >  
> >> From: Jisheng Zhang <jszhang@...nel.org>
> >>
> >> riscv doesn't implement architecture-optimized bitsearching functions
> >> such as find_first_{zero}_bit() etc.
> >>
> >> When GENERIC_FIND_FIRST_BIT=n, 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%.  
> > It seems this patch is missed. Is it possible to pick it up for 2nd 5.15-rc1 PR?
> >
> > Thanks  
> 
> It is enabled unconditionally by following commit
> 
> commit dbbccfe505ef8fae804677abf0564c1e07479102
> 
> Author: Yury Norov <yury.norov@...il.com>
> Date:   Tue Aug 24 09:59:56 2021 +1000
> 
>      arch: remove GENERIC_FIND_FIRST_BIT entirely
> 

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

thanks