All of lore.kernel.org
 help / color / mirror / Atom feed
From: Nam Cao <namcao@linutronix.de>
To: Jisheng Zhang <jszhang@kernel.org>,
	Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/3] riscv: word-at-a-time: improve find_zero() without Zbb
Date: Tue, 22 Sep 2026 15:50:24 +0200	[thread overview]
Message-ID: <87pky5e6ov.fsf@yellow.woof> (raw)
In-Reply-To: <20260908235312.8440-3-jszhang@kernel.org>

Jisheng Zhang <jszhang@kernel.org> writes:
> Previous commit improved the find_zero() performance for !RISCV_ISA_ZBB.
> What about RISCV_ISA_ZBB=y but the HW doesn't support Zbb? We have the
> same heavy generic fls64() issue.

This patch separation makes sense in your first version. Now it makes
more sense to squash this part to the first patch.

...
> To remove non-necessary zero bits couting on RV32, we also replace the
> 'fls64(mask) >> 3' with '!mask ? 0 : ((__fls(mask) + 1) >> 3);'

This should be its own patch.

Nam

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply	other threads:[~2026-09-22 13:50 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-08 23:53 [PATCH v3 0/3] riscv: word-at-a-time: improve find_zero() Jisheng Zhang
2026-09-08 23:53 ` [PATCH v3 1/3] riscv: word-at-a-time: improve find_zero() for !RISCV_ISA_ZBB Jisheng Zhang
2026-09-08 23:53 ` [PATCH v3 2/3] riscv: word-at-a-time: improve find_zero() without Zbb Jisheng Zhang
2026-09-22 13:50   ` Nam Cao [this message]
2026-09-08 23:53 ` [PATCH v3 3/3] riscv: word-at-a-time: improve find_zero() for Zbb Jisheng Zhang

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=87pky5e6ov.fsf@yellow.woof \
    --to=namcao@linutronix.de \
    --cc=alex@ghiti.fr \
    --cc=aou@eecs.berkeley.edu \
    --cc=jszhang@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=palmer@dabbelt.com \
    --cc=pjw@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.