All of lore.kernel.org
 help / color / mirror / Atom feed
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Anton Blanchard <anton@samba.org>
Cc: paulus@samba.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] powerpc: Speed up clear_page by unrolling it
Date: Thu, 2 Oct 2014 09:17:55 -0500	[thread overview]
Message-ID: <20141002141755.GA13453@gate.crashing.org> (raw)
In-Reply-To: <20141002154421.62073027@kryten>

On Thu, Oct 02, 2014 at 03:44:21PM +1000, Anton Blanchard wrote:
> This assumes cacheline sizes won't grow beyond 512 bytes or
> page sizes wont drop below 1kB,

Or a combination of those.

> Michael found that some versions of gcc produce quite bad code
> (all multiplies), so we give gcc a hand by using shifts and adds.

You can make the code a lot less cluttered as well as making the
generated code independent of compiler version by writing the setup
of twox..eightx in the asm block itself.


Segher

      reply	other threads:[~2014-10-02 14:18 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-02  5:44 [PATCH v2] powerpc: Speed up clear_page by unrolling it Anton Blanchard
2014-10-02 14:17 ` Segher Boessenkool [this message]

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=20141002141755.GA13453@gate.crashing.org \
    --to=segher@kernel.crashing.org \
    --cc=anton@samba.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=paulus@samba.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.